Abstracts : 31 st European Congress of Pathology.

Sunday, 8 September 2019, 17:15 - 19:15, Meeting Room Clio CP-03 | 1-Day Computational Pathology Symposium – Selected Abstracts Sunday, 8 September 2019, 17:15 - 19:15, Meeting Room Clio CP-03 | 1-Day Computational Pathology Symposium – Selected Abstracts CP-03-001 Deep learning enables fully automated mitotic density assessment in breast cancer histopathology M. Balkenhol 1 , P. Bult 1 , D. Tellez 1 , W. Vreuls 2 , P. Clahsen 3 , F. Ciompi 1 , J. van der Laak 1 1 Radboud University Medical Center, The Netherlands, 2 Department of Pathology, Canisius-Wilhelmina Hospital, Nijmegen, The Netherlands, 3 Haaglanden Medical Center, The Netherlands Background & Objectives: Mitosis counting is an important part of breast cancer grading, yet known to suffer from observer variability. Advances in machine learning enable fully automated analysis of digitized glass slides. The present study evaluated automatic mitosis counting and demonstrated applicability on triple negative breast cancers (TNBC). Methods: A deep learning algorithm fully automatically detected mitoses in scanned H&E slides of 90 invasive breast tumours and determined the mitotic hotspot. Two independent observers assessed mitotic density on glass slides according to routine practice, and in the computer-defined hotspot. Automated mitotic counting was also performed in a TNBC cohort (n=597). Cox regression models were expanded with dichotomized mitotic counts, using the c-statistic to evaluate the additional prognostic value of every possible cut off value. Results: Automatic counting showed excellent concordance with visual assessment in computer detected hotspots with intraclass correlation coefficients (ICC) of 0.895 (95% CI 0.845–0.930) and 0.888 (95% CI 0.783–0.936) for two observers, respectively. ICC of fully automated counting versus conventional glass slide assessment were 0.828 (95% CI 0.750–0.883 and 0.757 (95% CI 0.638–0.839), respectively. In the TNBC cohort, none of the cut off values improved the models’ baseline c-statistic. Conclusion: Automatic mitosis counting is a promising complementary aid for mitoses assessment. Our method was capable of fully automatically locating the mitotic hotspot in tumours, and was capable of processing a large series of TNBC, showing that mitotic count was not prognostic for TNBC even when attempting alternative cut off points. This study was funded by a Junior Researcher grant from the Radboud University Medical Center Institute for Health Sciences (RIHS). CP-03-002 Automated grading of urothelial cell carcinoma of the bladder I. Jansen 1 , M. Lucas 1 , J. Bosschieter 2 , S. Meijer 3 , O. de Boer 3 , T. van Leeuwen 4 , H.A. Marquering 4 , J.A. Nieuwenhuijzen 2 , D.M. de Bruin 4 , C.D. Savci-Heijink 4 1 Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, The Netherlands, 2 Amsterdam UMC, location VUmc, The Netherlands, 3 Department of Pathology, Amsterdam UMC, University of Amsterdam, The Netherlands, 4 Amsterdam UMC, location AMC, The Netherlands Background & Objectives: Although histological grade is an important predictor for recurrence and progression in non-muscle invasive bladder cancer (NMIBC), the reproducibility is low. The aim of this study is to investigate the potential value of a deep learning architecture for the grading of urothelial cell carcinoma (UCC) of the bladder using histology slides of transurethral resection of bladder tumour (TURBT) specimen and assess its accuracy by the comparison with the consensus grading of three pathologists. Methods: Histological glass slides of patients with NMIBC who underwent a TURBT between 2000-2016 in three hospitals in the Netherlands were included. The slides were independently reviewed by three pathologists, assigning the WHO’73 and WHO’04 grade, resulting in a four-tiered grading scheme. The slides were digitized, manually annotated by an expert observer and subsequently checked by a uropathologist. Firstly, a U-Net was trained to segment urothelium. Based on these segmentations, an ImageNet pre-trained DenseNet was trained for automated grading of the urothelial lesions based on the consensus score of the three pathologists. Results: In total, 328 tissue samples of 232 patients were included. In 93% of the slides, the urothelium was accurately detected. In another 21% false positive regions were detected. Incorrect classification was mainly in slides with extensive color loss or in regions with inflammation. Detailed data on the UCC grading will be presented at the conference. Conclusion: This feasibility study demonstrates the potential value of deep learning methods in classification of urothelial lesions. I Jansen and M Lucas are paid by ITEA3. Grant number: ITEA151003. CP-03-003 Unsupervised anomaly detection: application to colorectal liver metastasis A. Serag 1 , P. Maxwell 2 , J. Diamond 1 , A. Ion-Margineanu 1 , A. Kennedy 1 , R. McMillan 1 , H. Qureshi 1 , M. Saint Martin 1 , M. Salto-Tellez 2 , P. Hamilton 1 , P. O'Reilly 1 1 Philips Digital & Computational Pathology, United Kingdom, 2 Queen's University Belfast, United Kingdom Background & Objectives: The building of deep learning models needs large amounts of data with annotated examples. Obtaining expert labels for such models is difficult since detailed annotation is time-consuming. Here, we present an unsupervised learning approach capable of identifying anomalous patterns that can serve as imaging biomarker candidates. We show the application of the proposed approach for detecting colorectal metastases in liver biopsies. Methods: We propose to use unsupervised learning to create a rich generative model of normal (i.e. non-tumour) local anatomical appearance. We use generative adversarial networks to solve the problem of creating an adequately representative model of appearance, while at the same time learning a generative and discriminative component. We use information from both image space and latent space to differentiate between observations that conform to the training data and such data that does not fit. Results: The trained model is able to generate images that are visually similar to the non-tumour images. In the case of anomalous images (contain metastases), the pairs of input images and generated images show significant differences. The distributions of the anomaly score over non-tumour images from the training set and test set or over images extracted from metastatic cases show that the anomaly score is suitable for the classification of normal and anomalous samples (P<0.001 ). Conclusion: We presented an unsupervised approach for colorectal metastasis detection in liver biopsies. Training patches were extracted from non-tumour images; avoiding the necessity of having detailed pathologist annotation. The approach may be applied across the whole range of computational pathology problems. CP-03-004 Automated Ki67 hot-spot detection and analysis leads to higher Ki67 proliferation indices M. Zwager 1 , T. Koopman 1 , H. Buikema 1 , D. Omanovic 2 , A. Schønau 2 , H. Klingberg 2 , B. van der Vegt 1 1 University of Groningen, University Medical Center Groningen, The Netherlands, 2 Visiopharm A/S, Hørsholm, Denmark Background & Objectives: It is suggested that Ki67 proliferation hot-spot scoring is a prognostic and predictive marker in breast cancer. However, visual identification of Ki67 hot-spots is difficult and manual scoring is labour-intensive and prone to inter- and intra-observer variability. Automated detection and scoring of Ki67 hot-spots by digital image analysis (DIA) could aid in a standardised and reproducible assessment of the Ki67 proliferation index. The aim of this study was to compare manual Ki67 hot-spot detection and scoring with DIA Ki67 hot-spot detection and scoring. Methods: Whole tissue sections of 117 consecutive invasive breast carcinomas were immunohistochemically stained for Ki67. Firstly, Ki67 hot-spots were detected by two independent observers and scored using a validated manual counting protocol. Secondly, manual Ki67 scores were compared with DIA on these manually annotated hot-spots. Thirdly, automated Ki67 hot-spot detection and Ki67 calculation was performed using DIA. Inter-observer agreement between manual scores and DIA in manually annotated hot-spots, and between manual observers was assessed using the coefficient of determination (R 2 ). Means of manual scoring and DIA results were compared. Results: 102 cases were available for assessment. Correlation between both manual observers was suboptimal (R 2 =0.78). Manual and DIA Ki67 scores in manually annotated hot-spots showed a strong correlation (R 2 =0.90). Hot-spot detection by DIA (mean: 39.0%) led to higher hot-spot scores compared to manual scoring (means: 33.4% and 29.4%). Conclusion: Automated Ki67 hot-spot detection and analysis is a reliable method that leads to higher hot-spot Ki67 proliferation indices. CP-03-005 U-Net ensembles for accurate classification of oesophageal adenocarcinoma B. Cardenas Guevara 1 , V. van Oijen 1 , D. Worrall 1 , K. de Laat 2 , M. van der Wel 2 , M. Lucas 3 , I. Jansen 3 , H. Marquering 3 , D. de Bruin 3 , D. Savci-Heijink 2 , O. de Boer 2 , S. Meijer 2 1 Amsterdam Machine Learning Lab, University of Amsterdam, The Netherlands, 2 Department of Pathology, Amsterdam UMC, University of Amsterdam, The Netherlands, 3 Department of Biomedical Engineering and Physics, Amsterdam UMC, University of Amsterdam, The Netherlands Background & Objectives: Oesophageal adenocarcinoma has a dismal prognosis and Barrett’s oesophagus (BE) is the only known precursor lesion. BE progresses through a metaplasia-dysplasia-carcinoma sequence. Progression rates from non-dysplastic BE (NDBE) are low (0,5%), but a histopathological diagnosis of low grade dysplasia (LGD) is a strong independent risk factor for progression. As a result of significant interobserver variation, reported progression rates vary from 1- 40% and therefore International guidelines mandate a second opinion by an expert-pathologist. We aim to develop a convolutional neural network for objective and reproducible diagnosis of dysplasia in BE at expert-pathologist level. Methods: TIFF images from 400 digitized biopsies of 170 BE patients were annotated in high detail by an expert pathologist, generating binary classification masks for NDBE and dysplastic glands. Patches of the H&E staining and corresponding binary mask were extracted, resulting in 148.033 and 34.557 patches for training and testing, respectively. An ensemble of U-Nets was used, using a combination of the U-Net architecture with DenseNet and ResNet models, pre-trained on ImageNet. The ensemble consisted of four U-Nets with a down-sampling path using the DenseNet architecture and four other U-nets using the ResNet architecture. As metrics F1 coefficient and the pixel-wise accuracy was used. Results: F1 scores (range 80.6 and 84.9%) and pixel-wise accuracy (range 86.5 to 90.6%) of individual models and combinations; the best performing combination was the ensemble consisting of a committee of eight DenseNet and ResNet models. Model F1-score Pixel-wise accuracy U-Net 80,6% 86,5% U-Net + ResNet-34 81.9 % 87.6 % U-Net + ResNet-152 83.1 % 88.9 % U-Net + DenseNet-161 82.8 % 88.1 % Ensemble DenseNet and ResNet 84.9 % 90.6 % Conclusion : U-Net ensembles that classify precursor lesions of oesophageal adenocarcinoma can be used for accurate risk stratification of patients with BE. CP-03-006 Artificial intelligence driving automated pathology: iCAIRD and beyond P. Caie 1 , N. Dimitriou 1 , I.P. Nearchou 1 , O. Arandjelović 1 , D. Harrison 1 1 University of St Andrews, United Kingdom Background & objectives : Artificial Intelligence (AI) can be trained to recognise complex patterns and morphology within digitised histopathology specimens and use them to aid clinical reporting. These patterns may be already known, where the pathologist trains the AI model. However, cancer is a complex disease and the tissue may harbour undiscovered but clinically significant morphological patterns. AI can also be used to identify and report such novel features without human bias and error. This talk will demonstrate how the two above methodologies were successfully used in colorectal (CRC) and bladder cancer examples and how they will be used for the automatic reporting of gynaecological specimens in the iCAIRD initiative. Methods: Machine learning workflows were designed to analyse unbiasedly extracted data from the automated analysis of immunofluorescence labelled urine cytology (n=624) and whole slide CRC specimens (n=173). H&E labelled whole slides of CRC were analysed using AI after both pathology trained feature recognition (n=650) and without any human direction (n=75). Results: Bladder cancer diagnosis was reported from urine cytology samples with 95% sensitivity and 70% specificity. CRC survival was predicted with an AUROC of 0.94 in the immunofluorescence labelled cohort using 123 automatically extracted features and with >95% accuracy in the H&E stained digitised slides when applying no human input. Conclusion: The use of AI allows clinically significant features to be reported with or without human training and error. This work demonstrates AI’s ability to automatically report clinical specimens and how the technology can track toward clinical translation such as with the iCAIRD initiative. CP-03-007 Implementation of the ContextVision INIFY(TM) tool for the automatic detection of prostatic cancer in a fully digital routine workflow F. Fraggetta 1 , S. Lionti 1 , G. Giuffrida 1 , C. Emmanuele 1 , P. Pepe 2 1 Pathology Unit Cannizzaro Hospital, Italy, 2 Urology Unit Cannizzaro Hospital, Italy Background & Objectives: Validation of an Artificial Intelligence (AI) prototype tool INIFY TM (ContextVision Company, Sweden) for the detection of prostatic cancer in bioptic samples were evaluated ia fully digital pathology laboratory at Cannizzaro Hospital in Catania, Italy Methods: The procedure included the following steps: integration with the local laboratory information system (LIS) (Pathox ver.13) and possibility to open the INIFY TM web viewer. All cases submitted were confirmed by expert pathologists. Results: The integration with the local LIS was obtained using a specific HL7 connection. between LIS and INIFY TM AI tool without problems. According to a default protocol only Whole Slide Images (WSI) belonging to prostatic bioptic samples were automatically submitted for analysis at the end of the scanning session, without need of manual intervention. After analysis the results were available within the virtual tray of the case: flipped image if cancer. A total of 4746 WSI of prostatic cancers were submitted to INIFY TM tool, with a success rate of 100%. The prototype tool showed high specificity at recognizing cancer but low sensitivity. However by using the INIFY TM viewer all the suspicious area were indicated. Conclusion: The installation of ContextVision INIFY TM in the Catania Digital Pathology department showed a successful integration of this AI tool in a fully digital workflow, facility to use, working as computer-aided diagnosis. This tools could be a helpful instrument in a digital routine. Monday, 9 September 2019, 08:30 - 09:30, Meeting Room Clio MD-01 | 2-Day Molecular Diagnostics Symposium – Selected Abstracts Monday, 9 September 2019, 08:30 - 09:30, Meeting Room Clio MD-01 | 2-Day Molecular Diagnostics Symposium – Selected Abstracts MD-01-001 Plasma cfDNA testing of patients with EGFR mutant non-small cell lung cancer: droplet-digital PCR versus next-generation sequencing compared to tissue-based results C.M. Steendam 1,2 , P.N. Atmodimedjo 1 , E. de Jonge 1 , M.S. Paats 1 , C. van der Leest 2 , E. Oomen - de Hoop 1 , J.H. von der Thüsen 1 , W.N. Dinjens 1 , R.H. van Schaik 1 , J.G. Aerts 1 , H.J. Dubbink 1 1 Erasmus MC, Rotterdam, The Netherlands, 2 Amphia Hospital, Breda, The Netherlands Background & Objectives: To compare the results of plasma cell-free DNA (cfDNA) droplet-digital PCR (ddPCR) and next generation sequencing (NGS) on detection of Epithelial Growth Factor Receptor (EGFR) primary activating mutations and p.T790M with results of tissue analysis in patients with EGFR mutated non-small cell lung cancer (NSCLC). Methods: All patients with EGFR mutated NSCLC for which a pathology and a plasma specimen were available upon progression between November 2016 and July 2018 were selected. Concordance, Cohen’s kappa and intraclass correlation coefficients were calculated. Results: Plasma cfDNA and pathology specimens of 36 patients were analysed. Agreement between ddPCR and NGS was 86% (κ=0.63) for the primary activating mutation and 94% (κ=0.89) for p.T790M detection. Allele ratios were comparable with an intraclass correlation coefficient of 0,992 and 0,997 respectively. Discrepancies of some degree were found in 15 patients (41.7%). In 6 patients (16.7%), no mutations at all were detected in cfDNA. In 3 patients (8.3%), p.T790M was detected in plasma but not in pathology specimen, while in 3 other patients (8.3%), p.T790M was demonstrated in the pathology specimen but not in plasma. Concordance of cfDNA and pathology for the primary activating mutation was 69% for ddPCR and 83% for NGS. For the detection of p.T790M this was 75% (κ=0.49) for ddPCR as well as for NGS. Conclusion: Mutual agreement is high between NGS and ddPCR in cfDNA on the level of a specific mutation, with comparable ratio results. Plasma testing of EGFR primary activating mutations and p.T790M shows high concordance with pathology results, for NGS as well as ddPCR, depending on the extent of the panel used. In NGS, more genetic aberrations can be investigated at once. This work was supported by AstraZeneca. MD-01-002 Circulating cell-free DNA in archived low-quality volume serum samples: rate of concordance with mutation in tumour D. Nasrollahzadeh 1 , B. Abedi-Ardekani 1 , T. Delhomme 1 , P.H. Avogbe 1 , M. Foll 1 , J. McKay 1 , P. Brennan 1 , R. Malekzadeh 2 1 International Agency for Research on Cancer/WHO, France, 2 Digestive Disease Research Institute Tehran, Iran Background & Objectives: Cell-free DNA (cfDNA) is considered as non-invasive method for cancer detection with high specificity and variable sensitivity. Mainstream cfDNA studies are based on qualified samples which is plasma kept at -80, with no cycle of re-thawing, and minimum volume of 1 ml. In some archival studies, such standards were not met. We aim to investigate feasibility of cfDNA detection in archival serum samples kept at -20 with several cycles of re-thawing and volume less than or equal to 0.7 ml. Methods: Leftover sera from a population-based study of oesophageal squamous cell carcinoma (ESCC) in Northern Iran- conducted 14 years ago- were used. Sera were applied for several serology assays and underwent between 4 and 6 cycles of re-thawing. TP53 mutation data from formalin-fixed paraffin-embedded ESCC tissues was available for one-third of the cases. We extracted cfDNA from 44 ESCC and 39 controls (matched for storage condition). 27 TP53 amplicons were deep sequenced on ion-torrent platform. Needlestack, a pipeline for calling variants with extremely low allelic fraction (AF) was applied. RVSB >0.85, Q-value<30, and minimum distance form highest AF <10 nt. were filtered. Results: We were able to detect 20% of tumour tissue mutations concordantly in CfDNA of archival sera. After applying filtrations, 59 unique mutations were detected in all cfDNAs, out of them 24 were exclusively detected in ESCC cases and 29 found just in controls. None of the tumour mutations was detected among controls. One likely non-germline cfDNA mutation was detected in both case and control which had significantly higher AF in case than control. Conclusion: Applying our method, detection rate of concordant TP53 mutations in archived low- volume sera and cancerous tissue is comparable to results of the same gene in well-kept plasma. These results suggest the crucial role of bioinformatics pipeline in detectability of variants in cfDNA comparing to quality of sample. TP53 variants in healthy resident of ESCC endemic area warrants further investigation. MD-01-003 Global delivery of external quality assessment for lung cancer liquid biopsy testing J. Fairley 1 , M. Cheetham 2 , M. Denis 3 , E. Dequeker 4 , C. Keppens 4 , F. Fenizia 5 , N. Normanno 5 , S. Patton 6 , E. Rouleau 7 , E. Schuuring 8 , K. Van Casteren 9 , Z. Deans 1 1 GenQA/UKNEQAS, United Kingdom, 2 EMQN, United Kingdom, 3 Gen&Tiss, France, 4 ESP, Belgium, 5 Istituto Nazionale Tumouri "Fondazione Giovanni Pascale", IRCCS, Naples, Italy, 6 European Molecular Genetics Quality Network (EMQN), Manchester Centre for Genomic Medicine, St Mary's Hospital, United Kingdom, 7 Department of Pathology and Medical Biology, Institut Gustave Roussy, Villejuif, France, 8 ESP, The Netherlands, 9 Biomedical Quality Assurance Research Unit, KU Leuven, Belgium Background & Objectives: Wide-spread implementation of cell free DNA (cfDNA) testing of plasma for cancer mutations requires quality assessment of these services to ensure patient safety. The international external quality assessment (EQA) provider consortium, IQNPath has delivered a second successful EQA run to determine the standard of cfDNA testing for lung cancer. Methods: Five European EQA providers, under the umbrella of IQNPath, collaborated to deliver the assessment during 2018-19 to a total of 320 laboratories from 44 countries. A panel of bespoke manufactured plasma samples with varying mutations at a range of allelic frequencies were validated by a range of methodologies prior to distribution to ensure stability and reproducibility. The EQA samples were supplied for testing and reporting according to laboratory routine protocols. Peer reviewed criteria was applied to assess the standard of genotyping and reporting. Results: The genotyping accuracy, variability of reporting content and formats will be discussed. Low allelic frequency samples were the most challenging and some methods did not detect these mutations. Reporting of such cases often did not address the risk that tumour DNA may have not been tested and limitations of the testing performed was not addressed when reporting the result. Conclusion: The variability in the standard of genotyping and reporting highlights the need for EQA in this field and educational guidance to ensure the delivery of high-quality clinical service where testing of cfDNA is the only option for clinical management. MD-01-004 Reflex tumour BRCA1/2 testing in ovarian carcinomas to stratify PARP inhibitor treatment and germline diagnostics M. Ligtenberg 1 , J.R. Vos 2 , I.E. Fakkert 2 , J.A. de Hullu 3 , A.M. van Altena 3 , A.S. Sie 2 , H. Ouchene 2 , R.W. Willems 1 , I.D. Nagtegaal 1 , M.C. Jongmans 2 , A.R. Mensenkamp 2 , G.H. Woldringh 2 , J. Bulten 1 , E.M. Leter 4 , C.M. Kets 2 , M. Simons 1 , N. Hoogerbrugge 2 1 Department of Pathology, Radboud University Medical Center, Nijmegen, The Netherlands, 2 Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands, 3 Department of Obstetrics and Gynaecology, Radboud University Medical Center, Nijmegen, The Netherlands, 4 Department of Clinical Genetics, Maastricht University Medical Center, The Netherlands Background & Objectives: Women with ovarian carcinoma have a higher chance to benefit from PARP inhibitor therapy if their tumour has a somatic or germline BRCA1/2 pathogenic variant. Germline BRCA1/2 testing allows therapeutic and preventive choices in patients and family members. This study evaluates the feasibility, effectiveness, and appreciation of reflex tumour BRCA1/2 testing in newly diagnosed ovarian carcinoma patients to stratify patients for PARP inhibitor therapy and predisposition testing. Methods: Reflex tumour BRCA1/2 testing of newly diagnosed ovarian carcinomas was evaluated in seven hospitals between October 2015 and June 2017. Diagnostic yield, uptake, referral rates for genetic testing, and experiences of patients and gynecologists were evaluated. Results: Reflex tumour BRCA1/2 testing was performed for 315 (78%) of 406 eligible samples and was successful in 305 (97%). In 51 ovarian carcinomas a pathogenic BRCA1/2 variant was detected (17%). Genetic counseling and germline testing was performed in 44 patients, revealing that 57% of the mutations were hereditary. Most participating gynecologists and patients were positive about the workflow. Conclusion: Reflex tumour BRCA1/2 testing in all newly diagnosed ovarian carcinoma patients to find somatic and germline BRCA1/2 variants is feasible, effective and appreciated by patients and gynecologists. It serves as an effective pre-screen for genetic counselling and germline diagnostics. It extends personalised treatment choices based on tumour BRCA1/2 status to patients with somatic pathogenic variants and patients that do not opt for hereditary testing. This work was financially supported by AstraZeneca and is presented on behalf of the OPA working group. MD-01-005 Exploitation of cfDNA extracted from bile as liquid biopsy source in pancreatobiliary cancers C. Driescher 1 , K. Ebner 2 , W. Goering 1 , L. Haeberle 1 , V. Keitel 2 , D. Haeussinger 2 , I. Esposito 1 1 Institute of Pathology, Heinrich Heine University and University Hospital, Düsseldorf, Germany, 2 Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich Heine University and University Hospital, Düsseldorf, Germany Background & Objectives: To date, accepted biomarkers in pancreatobiliary cancers lack sensitivity and specificity and diagnosis often requires invasive procedures. Therefore, there is an urgent need for reliable biomarkers allowing easy and repeatable sampling to ensure dynamic real-time evaluation of tumour biology. Compared to classic histopathological analysis, liquid biopsy is a less-invasive method, which detects cell-free DNA (cfDNA) released into body fluids from primary or metastatic tumours. cfDNA contains tumour-specific aberrations with possible prognostic and predictive value. Methods: We extracted cfDNA from bile obtained from patients with pancreatobiliary cancers (n=12) during routine diagnostic procedures. Tumour-specific aberrations were detected by next generation sequencing using a panel of 50 oncogenes and tumour suppressor genes on a S5 Sequencing platform. Matched tumour tissue (n=7) served as control. Results: Sequencing of cfDNA obtained from bile showed concordance with somatic mutations found in tumour tissues in 92% of cases. Eleven out of twelve mutations found in the tumour tissue were concordantly present in cfDNA sequencing results. In one case, an additional KRAS mutation was found in cfDNA, showing the ability of liquid biopsies to better display tumour heterogeneity. In cases were sequencing from tissue failed, e.g. due to insufficient DNA quality, cfDNA analysis could provide information about the mutational status of the tumour. Conclusion: Overall, cfDNA sequencing provided additional information about tumour heterogeneity and sufficiently replaced tissue sequencing when aforementioned was not feasible. Therefore, cfDNA sequencing of bile represents a reliable method for detecting tumour mutations avoiding possible complications and limitations of tissue sampling in pancreatobiliary cancers. Although primary diagnosis still needs histologic confirmation, liquid biopsies obtained from bile enable disease monitoring (e.g. in primary non-resectable cancers) using less invasive procedures. Tuesday, 10 September 2019, 08:30 - 09:30, Meeting Room Clio MD-05 | 2-Day Molecular Diagnostics Symposium – Selected Abstracts Tuesday, 10 September 2019, 08:30 - 09:30, Meeting Room Clio MD-05 | 2-Day Molecular Diagnostics Symposium – Selected Abstracts MD-05-001 Differentially expressed immune related genes in metastatic vs. non-metastatic LUMA, LUMB1 and TNBC primary breast carcinoma cases A.M. Tokes 1 , O. Rusz 1 , C. Pollner-Szundi 1 , L. Madaras 1 , A. Kovács 1 , B.î Molnár 2 , I.î Vári-Kakas 3 , J. Kulka 1 1 Semmelweis University Budapest, 2nd Department of Pathology, Hungary, 2 Semmelweis University Budapest, 1st Department of Surgery, Hungary, 3 University of Oradea, Department of Computers and Information Technology, Romania Background & Objectives: It is increasingly clear that tumour progression largely depends of the cancer cell–stromal immune cell environment interaction. The aim of the study is to define the immune gene signature associated with metastatic potential of LUMA, LUMB1 and TNBC cases by using Nanostring technology. Methods: We compared mRNA levels of 730 immune-related genes by using Nanostring technology in 35 primary breast carcinoma (BC) cases (12 LUMA (6 non-metastatic (NM) and 6 metastatic (M) BC), 11 LUMB1 (5NM and 6M) and 12 TNBC (6NM and 6M)) presenting ≥1% stromal TIL and with a minimum 6 year available follow up data. TIL was assessed on HE stained slides. Results: The highest TIL ratio was observed in NM TNBC cases (mean-9, 66%) and the lowest in M LUMA cases (mean 1,16%). In M LUMA BCs compared to NM LUMA BCs we observed differences in genes mostly related to chemokines, cytokines and cell functions. Whereas CXCL14, CCL3L1, CCL28 considered to be associated with metastases presented higher expression in M LUMA BCs, BTLA, LTA, and GZMB were detected in lower amount. The significantly different gene set in metastatic vs. non metastatic LUMB1 BCs and TNBCs was more heterogeneous compared to LUMA BCs. Significantly upregulated genes in metastatic LUMB1 BCs and TNBCs compared to non-metastatic ones were VEGFA, CLEC5A, CCL28, CFB in LUMB1 and DUSP4, PPARG, GATA3, ALCAM in TNBC cases. Conclusion: Genes involved in cancer immunity most probably related to tumour progression vary considerably among breast carcinoma subtypes. The involvement of chemokines and their receptors in breast cancer metastasis is only partly clear and needs further investigation. NVKP_16-1-2016-0004 MD-05-002 Tumour mutational burden analysis: implementation in routine diagnostics L. Kroeze 1 , E. Kamping 2 , D. von Rhein 2 , E. Jansen 2 , R. de Voer 2 , M. Barberis 3 , J. Botling 4 , E. Garrido-Martin 5 , F. Haller 6 , L. Lacroix 7 , B. Maes 8 , S. Merkelbach-Bruse 9 , V. Pestinger 10 , N. Pfarr 11 , A. Stenzinger 12 , K. Grünberg 1 , M. Ligtenberg 1 1 Department of Pathology, Radboud University Medical Center, Nijmegen, The Netherlands, 2 Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands, 3 Division of Pathology and Laboratory Medicine, European Institute of Oncology, Milan, Italy, 4 Department of Immunology, Genetics and Pathology, Uppsala University, Sweden, 5 Instituto de Investigación, University Hospital 12 de Octubre, Spanish National Center for Cancer Research (CNIO) and CIBERONC, Madrid, Spain, 6 Institute of Pathology, University Hospital Erlangen, Germany, 7 Department of Medical Biology and Pathology, Institute Gustave Roussy, Villejuif, France, 8 Laboratory for Molecular Diagnostics, Department of Clinical Biology, Jessa Hospital, Hasselt, Belgium, 9 Institute of Pathology University Hospital of Cologne, Germany, 10 Institute of Cancer & Genomic Science, University of Birmingham, United Kingdom, 11 Institute of Pathology, Technical University Munich, Germany, 12 University Hospital Heidelberg, Germany Background & Objectives: Although the introduction of immunotherapy has benefitted many patients, more than half of the patients show no clear evidence of response, underlining the urge for new predictive biomarkers. Recent studies show that, in addition to PDL1 expression and microsatellite instability (MSI), tumour mutational burden (TMB; number of mutations/Mb) is an important novel biomarker that improves the selection of patients who could benefit from immunotherapy. Methods: The TruSight Oncology 500 assay (TSO500, 523 cancer-related genes, 1.94Mb, Illumina) was tested for the determination of TMB, MSI, mutations and copy number variations (CNVs) on formalin-fixed paraffin-embedded material (n=55) Results: Our validation indicates that the assay can clearly discriminate between samples with low (normal tissue) and high TMB. Use of 40 ng DNA is recommended, but results using 15 ng are comparable. All known CNVs (n=9) and pathogenic mutations (n=59) were detected, although 2 out of 6 complex indels (45 and 48 nucleotides) were not annotated by the TSO500 bio-informatic pipeline. Furthermore, our validation shows that the tumour cell percentage can influence the TMB value; a biological problem unrelated to the assay, but caused by heterogeneity of the variant allele frequencies due to an underlying deficiency in DNA repair. The TMB analysis is highly reproducible within and among laboratories (n=11), for which DNA from a third party was used. Conclusion: The TSO500 assay can be used to perform comprehensive genetic analysis (mutations, CNVs, MSI and TMB) in a single assay using only 15 ng of DNA and can replace current more targeted NGS analyses. This work was supported by Illumina, Bristol-Myers Squibb. MD-05-003 Role of HR23b in response to HDAC inhibitors and their effect on immunotherapy targets S. Wagener-Ryczek 1 , C. Alidousty 1 , C. Heydt 2 , J. Fassunke 1 , S. Merkelbach-Bruse 2 , R. Buettner 1 , M.A. Ihle 1 1 University Hospital Cologne, Germany, 2 Institute of Pathology University Hospital of Cologne, Germany Background & Objectives: Deregulation of histone deacetylases (HDACs) plays an important role in tumourigenesis. Restoring a regular acetylation profile by HDAC inhibitors (HDACi) is a promising therapeutic approach. Human Rad Homolog B (HR23b), has been identified as a predictive biomarker and we showed previously that HDACi also exhibit antiproliferative and pro-apoptotic effects in sarcomas depending on HR23b expression. We therefore aim to elucidate the regulatory relationship between HR23b expression and sensitivity towards HDACi as well as its effect on immunotherapy marker. Methods: A stable knockout of HR23b was generated in a malignant peripheral nerve sheath tumour (MPNST) cell line using CRISPR /Cas9-technology. Proliferation and apoptosis was measured with the ApoTox™Glo assay. Vorinostat was administered at IC 50 concentration to wildtype and HR23b KO cells. Afterwards expression analysis of important signalling pathways was performed with the nCounter PanCancer Pathways panel. Furthermore, the effect of HDACi on key immunotherapy targets was investigated using a customised NanoString expression panel. Results: We could show that HR23b dependent sensitivity towards HDACi is mediated by apoptosis induction via death receptor pathways. In contrast, HR23b loss reduces apoptosis induction and shifts response to autophagy. Furthermore, we observed a significant upregulation of anticancer immunotherapy targets (e.g. cancer testis antigens) enhancing the response to immunotherapy agents. Conclusion: Understanding key pathways of HDACi induced apoptosis and the importance of HR23b as a predictive biomarker should help to select patients who may benefit from HDACi therapy. Especially the ability to enhance the endogenous antitumour activity as well as the upregulation of possible immunotherapy targets might enable promising combinatorial treatments. MD-05-004 MET exon 14 skipping mutations in non-small cell lung cancer: efficient routine diagnostics, histopathology and clinical response upon targeted treatment W. Geurts-Giele 1 , M. Pruis 2 , J. von der Thusen 3 , I. Meijssen 1 , W. Dinjens 4 , J. Aerts 3 , M. Lolkema 2 , M. Paats 5 , H.J. Dubbink 6 1 Pathology, Erasmus MC Cancer Institute, The Netherlands, 2 Medical Oncology, Erasmus MC Cancer Institute, The Netherlands, 3 Erasmus Medical Center, Rotterdam, The Netherlands, 4 Erasmus University Rotterdam, Netherlands, 5 Pulmonary Diseases, Erasmus MC Cancer Institute, The Netherlands, 6 Erasmus MC, Rotterdam, The Netherlands Background & Objectives: Non-small-cell lung cancer (NSCLC) is one of the solid malignancies with the most evolved personalised treatments based on molecular characteristics of the tumour. Mutations in EGFR , HER2 and BRAF , translocations of ALK , ROS1 , RET and amplification of MET all lead to specific treatment options. Recently, in 2-4% of lung adenocarcinoma MET gene mutations leading to skipping of exon 14 were found, making patients eligible for treatment with MET tyrosine kinase inhibitors. We will present our experience with routine detection of MET exon 14 skipping mutations, histological features of MET mutated tumours and clinical follow-up of these patients. Methods: Since 2015 our custom-made DNA-based pan-cancer NGS panel for routine molecular diagnostics was supplemented with four amplicons for detection of MET exon 14 skipping mutations. Putative MET exon 14 skipping mutations were evaluated for their effect on splicing by RT-PCR if sufficient tissue was available. Histopathological characteristics and clinical follow-up were investigated for all MET mutated NSCLC. Mutation frequency was calculated including all routine diagnostic requests on NSCLC for therapeutic purposes from January 2016 to May 2018. Results: Of 1497 cases of NSCLC tested for therapeutic purposes in a 29-month period, 31 patients (2%) were identified with a MET exon 14 skipping mutation. In silico comparison with published data shows that our amplicon based NGS assay can detect up to 96% of MET exon 14 skipping mutations. In total, 46 cases of NSCLC with MET exon 14 skipping were detected (including 4 non-therapeutic requests and 11 requests outside the 29-month period). This concerned 34 unique mutations, of which 26 were confirmed by RNA analysis. The histologically evaluable tumours in this cohort (n=30) had a varied morphology, with pleomorphic / sarcomatoid (n=12) as well solid-type adenocarcinoma (n=9) comprising the majority, but also including non-mucinous lepidic-type adenocarcinoma / adenocarcinoma in-situ (n=7) and acinar (n=2) patterns. Eleven patients with MET exon 14 skipping mutations received targeted therapy; they either participated in clinical trials or received Crizotinib in compassionate use. We will present clinical responses for the 5 patients treated with Crizotinib. Conclusion: MET exon 14 skipping mutations can be reliably detected in routine pathology tissue samples using DNA-based NGS analysis. Routine identification of MET exon 14 skipping mutations adds substantially to personalised targeted treatment strategies for NSCLC patients. MD-05-005 The diagnostic landscape and yield of predictive somatic molecular analyses for stratification of cancer therapy in the Netherlands E. Steeghs 1 , E.K. de Jong 1 , R.W. Willems 1 , Q.J. Voorham 2 , P.A. Seegers 2 , K. Grünberg 1 , M.J. Ligtenberg 1,3 1 Department of Pathology, Radboud University Medical Center, Nijmegen, The Netherlands, 2 PALGA: The Nationwide Network and Registry of Histology and Cytopathology, Houten, The Netherlands, 3 Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands Background & Objectives: Unequal uptake of predictive analyses for cancer therapy, the rapid increase of molecular markers and targeted therapies, and detection of variants of unknown significance indicate the need for standardization and evaluation of predictive diagnostics. We studied molecular analyses (i.e. techniques, diagnostic yield) for gastrointestinal stromal tumours (GIST), melanoma, colorectal carcinoma (CRC), and non-small cell lung cancer (NSCLC) in the Netherlands. Methods: Pathology reports containing predictive analyses are collected from all 46 pathology departments via the Dutch Pathology Registry (PALGA) between October 2017 and June 2019. Results: In the first year, predictive molecular analyses for GIST (n=255), melanoma (n=1205), CRC (n=2325), and NSCLC (n=3355; evaluation of 6 months) were performed in 14, 22, 22, and 21 pathology departments, respectively. Targeted NGS was predominantly used (>80% for GIST, CRC, NSCLC, and >60% for melanoma), but also MassARRAY and single gene analyses were performed. In total 31% of the analysed patients may benefit from targeted therapies, defined by alterations in KIT or PDGFRA for GIST (88%), BRAF for melanoma (45%), EGFR , BRAF , MET , ERBB2 , ALK , or ROS1 (18%) for NSCLC, or absence of KRAS , NRAS , and BRAF mutations (36%) in CRC. Moreover, variants associated with resistance, that give access to clinical trials, and variants of unknown significance were reported. Conclusion: We present an overview of the diagnostic landscape of predictive molecular analyses in the Netherlands. Next, these results will be enriched with clinical characteristics to obtain insight into the uptake of the molecular tests and their use in treatment decisions. This work is part of the research programme Personalised Medicine, financed by the Netherlands Organisation for Health Research and Development (ZonMw, project number 846001001).

Sunday, 8 September 2019, 09:30 - 10:30, Agora 3 PS-CP-01 | 1-Day Computational Pathology Symposium Sunday, 8 September 2019, 09:30 - 10:30, Agora 3 PS-CP-01 | 1-Day Computational Pathology Symposium PS-CP-01-001 Can image recognition techniques on whole slide images of colorectal polyps help in the identification of areas of high grade dysplasia? P. De Paepe 1 , J. Van Huysse 2 , A. Driessen 3 , P. Niville 4 , W. Van Laer 4 , K. De Wolf 4 1 AZ Sint-Jan, Brugge-Oostende, Dept of Pathology, Belgium, 2 AZ St Jan Brugge-Oostende, Dept of Pathology, Belgium, 3 University Hospital Antwerp, Dept of Pathology, Belgium, 4 Ixor, cvba Schuttersvest 75 2800 Mechelen, Belgium Background & Objectives: Colorectal screening programs have resulted in a significant increase in the number of colorectal polyps in daily pathology practice. The aim of the study is to design a model, based on deep learning techniques, that recognizes and indicates major zones of interest on whole slide digital images (WSI) of colorectal polyps. The zones of interest are: normal mucosa, zones with low grade dysplasia and zones with high grade dysplasia as defined by the WHO criteria. Methods: With a digital drawing tool three pathologists identified the zones of interest on 73 WSI. Only zones indicated by all three were used to design and train a first deep learning model focusing on pattern recognition. Each WSI was subdivided into tiles, 256x256 pixels. Next 9804 tiles, clearcut examples of the zones of interest, were selected to retrain the model. These tiles were subdivided into a training set (8656), a validation set (786) and a test set (362). Results: The final model reached a 75% accuracy on recognizing high grade dysplasia with a recall of 90% on the test set, 93% accuracy and 84% recall on low grade dysplasia and 77% accuracy and 81% recall on normal tissue. Conclusion; Our study demonstrates the possibility to develop a machine learning model that indicates zones of major interest in WSI’s. Improving our model among other by increasing the number of WSI for training, will allow us to develop a pre-diagnostic tool that offers support to the pathologist and may help to provide an accurate pathology report at appropriate time. PS-CP-01-002 Low discordance rate of digital diagnostics of histopathology compared to conventional microscopy - results from 1048 cases in a validation study S. Jarkman 1 , A. Bodèn 1,2 , B. Williams 3,4 , J. van der Laak 5 , D. Treanor 4 1 Department of Pathology, Linkoping University Hospital, Sweden, 2 Department of Clinical and Experimental Medicine, Linkoping University, Sweden, 3 Histopathology Department, St James University Hospital, Leeds, United Kingdom, 4 University of Leeds, United Kingdom, 5 Radboud University Medical Center, The Netherlands Background & Objectives: Since 2011 the Department of Anatomical Pathology in Linköping, Sweden, is routinely digitizing all histopathological glass slides. Implementation of a novel diagnostic modality requires careful validation. Our validation model is designed in cooperation with Leeds University Hospital, UK, and is adapted to the local circumstances. This validation study, ongoing since 2016, aims to investigate if diagnoses made digitally are concordant with traditional microscopic diagnoses. Methods: The validation model consisted of diagnosing sets of slides from different topographic areas with one training-step and one validation-step. The pathologist first read the cases digitally and directly afterwards using a microscope. Diagnostic discrepancies were recorded, as well as cases deferred to traditional microscopy. The training step consisted of approximately 20 slides. The validation step used a minimum of 60 cases. For pathologists validating more than one set, a minimum of 30 cases was used in subsequent sets. Results: We collected 18 sets (10 pathologists, 8 areas) corresponding to 1058 cases in the validation step. A total of 10 cases was excluded. Included were 1048 cases (approx. 10711 slides), while 24 cases (2.3%) were deferred to traditional microscopy. In 5 cases, a diagnostic discrepancy was recorded. The diagnostic concordance (deferred cases excluded) was 99.5%. Frequently commented discrepancies (not diagnosis-altering) regarded scanning- and tissue quality, cell details, mitoses, small objects and dysplasia. Conclusion: The diagnostic concordance of 99.5% between digital diagnostics and microscope indicates that digital microscopy is a safe alternative to traditional microscopy. Monday, 9 September 2019/Tuesday, 10 September 2019, 09:30 - 10:30, Agora 3 PS-MD-01 | 2-Day Molecular Diagnostics Symposium Monday, 9 September 2019/Tuesday, 10 September 2019, 09:30 - 10:30, Agora 3 PS-MD-01 | 2-Day Molecular Diagnostics Symposium PS-MD-01-001 Expression of Transient Receptor Potential Vanilloid-1 in gliomas vs medulloblastomas M. Assimakopoulou 1 , A. Moutafidi 1 , V. Zolota 2 , G. Gatzounis 3 1 Department of Anatomy-Histology and Embryology, School of Medicine, University of Patras, Greece, 2 University of Patras, School of Medicine, Greece, 3 Department of Neurosurgery, University Hospital of Patras, Greece Background & Objectives: The non-selective cation channels Transient Receptor Potential Vanilloid (TRPV) of TRP superfamily are activated by numerous stimuli and thus, may mediate downstream signalling. Previous data implicates alterations of TRPV1 expression in growth and progression of gliomas. Additionally, low or absent TRPV1 v3 variant expression has been strongly correlated with short survival in glioblastoma multiforme (WHO, grade IV) patients. The aim of this study was to investigate the expression levels of TRPV1 channel in gliomas and compare with embryonal tumours such as medulloblastomas. Methods: Immunohistochemistry was performed in formalin-fixed, paraffin-embedded tissue sections from 81 human brain tumours and samples from normal brain, using specific primary antibody against TRPV1. Analysis of immunoexpression was defined as the percentage of positive (labelled) cells out of the total number of tumour cells counted in ten non-overlapping fields (Labelling index, LI). The results were confirmed by immunofluorescence and qRT-PCR. Results: TRPV1 cytoplasmic localization was detected in tumour cells of gliomas and in neurons and a few glial cells of normal brain specimens. All medulloblastomas were TRPV1-immunonegative. In contrast, TRPV1-immunopositive gliomas (LI≥10) included 62.50% of diffuse fibrillary astrocytomas (WHO, grade II), 71.42% of anaplastic astrocytomas (WHO, grade III), 53.33% of glioblastomas multiforme (WHO, grade IV), 14.28% of oligodendrogliomas, and 33.33% of ependymomas. No significant association between TRPV1 channel expression and patients’ clinicopathological characteristics was found. Conclusion: Given the cellular heterogeneity, and the distinct cells of origin of different brain tumours, further functional studies would clarify the role of TRPV1 in biological behaviour of these tumours. PS-MD-01-002 Validation of a novel approach for molecular breast cancer classification S. Baldacchino 1 , J. Debattista 2 , C. Saliba 3 , C. Scerri 4 , G. Grech 1 1 Department of Pathology, University of Malta, Malta, 2 Applied Biotech Ltd, Malta, 3 Centre for Molecular Medicine and Biobanking, University of Malta, 4 Department of Physiology and Biochemistry, University of Malta Background & Objectives: The current breast cancer diagnostic workflow is subject to pre-analytic variables, interpretation and defined thresholds. Despite updated guidelines, equivocal and inter-laboratory disconcordance persist in current methodologies for HER2 assessment. The validation process for a novel molecular breast cancer classification method is outlined. Methods: 660 breast cancer specimens were cored (0.5mm) and arranged into a TMA. Cases selected were equally distributed as HER2 positive, negative or equivocal by immunohistochemistry. The TMA was assessed for HER2, ER and PR immunohistochemistry and HER2 FISH. TMA cores were then retrieved, lysed and analysed using a bead-based Quantigene assay. Data was controlled for quality and processed using a developed algorithm to classify molecular breast cancer subtypes. Results: In a pilot study (N=108) the Quantigene assay showed a 100% sensitivity and 93.5% specificity for HER2 detection. Considering the non-equivocal HER2 cases, Quantigene showed a 100% sensitivity and 100% specificity concordant with HER2 immunohistochemistry. Equivocal cases (2+) (n=35) tested by Quantigene show 100% Specificity and 80% Sensitivity compared to the HER2 FISH confirmatory result. Conclusion: A new molecular pathology tool has been developed for the classification of breast cancer using a diagnostic-ready approach with control material, minimal turnaround time and low cost. Supported by Project “Accurate Cancer Screening Tests” (ACT) financed by the Malta Council for Science & Technology through FUSION: The R&I Technology Development Programme 2016. PS-MD-01-003 Characterisation of genetic mutation spectra and identification of gene amplification and fusion variants in cell-free nucleic acid from cultured cancer cell media and liquid biopsy specimens using Oncomine™ pan-cancer cell-free assay R. Cao 1 , K. Lea 1 , J. Schageman 1 , K. Hanif 1 , Y. Li 1 , J. Gu 1 , V. Bagai 1 , P. Kshatriya 1 , A. Luchetti 2 , L. Quagliata 1 , H. Wikman 3 , S. Loges 3 , K. Bramlett 1 1 ThermoFisher Scientific, USA, 2 Thermo Fisher Scientific, Italy, 3 Department of Tumour Biology, Center of Experimental Medicine, University Medical Center Hamburg-Eppendorf, Germany Background & Objectives: Currently the standard practice in tumour biomarker research still relies on invasive tumour biopsy following by molecular testing or NGS assay. However, this only provides limited characterization of tumour composition. Recent studies in non-invasive biomarker research have demonstrated the potential advantages of using cell-free nucleic acids isolated from blood plasma to study genetic heterogeneity of tumour population and dissect the complex cancer clonal architecture. Methods: Recently developed Oncomine™ Pan-Cancer Cell-free Assay employs an amplification-based approach from Ion Torrent NGS technology and achieves exceptional sensitivity and specificity with input as little as 20 ng. It includes comprehensive genetic content to simultaneously interrogate both cfDNA and cfRNA. Results: In this study, cancer cell lines harboring multiple variant types were selected for evaluation. Using Pan-Cancer Cell-free Assay, we successfully detected all the expected variants in these cancer cell lines including gene amplification (MET, ERBB2, CDK4) and fusion variants (ALK fusion and MET exon skipping). Subsequently, we applied this assay to a set of liquid biopsy samples collected from a human subject with NSCLC during the course of 15 months. The results showed that a well-known TP53 mutation R248Q was consistently detected in the longitudinal samples. Interestingly, additional gene amplifications including MET, CDK4 and FGFR3 were identified at late time points, which were also confirmed by digital PCR and showed concordant with FISH analyses in solid tumour. Conclusion: Overall, this study demonstrates that Pan-Cancer assay provides a unique and complete NGS solution for comprehensive genetic mutation assessment using in vitro and in vivo liquid biopsy models. PS-MD-01-004 Case report: NGS of cell-free DNA from blood and bile as a follow-up strategy in a patient with metastatic pancreatic adenocarcinoma K. Ebner 1 , C. Driescher 2 , W. Goering 3 , L. Haeberle 2 , V. Keitel 1 , D. Haeussinger 1 , I. Esposito 2 1 Department of Gastroenterology, Hepatology and Infectious Diseases, Heinrich Heine University and University Hospital, Germany, 2 Institute of Pathology, Heinrich Heine University and University Hospital, Germany, 3 Institute of Pathology, Heinrich Heine University and University Hospital, Germany Background & Objectives: A 65-year-old patient initially presenting to our clinic with jaundice and weight loss was diagnosed with metastasized pancreatic ductal adenocarcinoma. After undergoing ERCP for biliary stent implantation, chemotherapy with Gemcitabin/nabPaclitaxel was initiated. After initial therapy response, we aimed at monitoring disease development by using a liquid biopsy approach with NGS analysis of cell-free DNA (cfDNA) extracted from serially collected blood and bile samples. Methods: Blood samples were collected at study inclusion and during outpatient-visits after 4, 7 and 14 weeks. Bile was collected at study inclusion and 7 weeks later during routine ERCP for biliary stent replacements. After cfDNA extraction and quantification, panel-based NGS analysis was performed using Ion-S5 next generation sequencing platform. Additionally, results were compared to mutation profiles obtained from tissue samples of the primary tumour. Results: During tumour progression, primary tumour mutations in TP53 and KRAS were detected in blood with rising allele frequencies (AF) from 13.9% and 13.2% after 4 weeks to 25% and 19.7% after 7 weeks. Bile-derived cfDNA after 7 weeks showed TP53 and KRAS mutations with AF of 5.5% and 4.4% compared to 0.3% and 0.2% at study inclusion. After modification of the chemotherapy-regimen, ultrasound-based detection of regression of liver metastases was accompanied by decreasing AF of TP53 and KRAS mutations in blood-cfDNA to 1.1% and 1.0%. Conclusion: This report suggests that mutation profiles of cfDNA from blood as well as bile might be useful in monitoring tumour development and therapy response. Larger cohort studies remain necessary to investigate the potential of this method for therapy-surveillance and possible benefits over routine biomarkers. PS-MD-01-005 Effect of radio-wave and molecular resonance surgery on rat neck skin regeneration I. Kastyro 1 , P. Pryanikov 2 , A. Alsufev 1,3 , V. Popadyuk 1 , A. Kovalenko 1 , A. Sedelnikova 1 , N. Kamanina 1 1 Peoples' Friendship University of Russia (RUDN University), Russia, 2 Pirogov Russian National Research Medical University (RNRMU), Russia, 3 Greenberg City Clinical Hospital Perm, Russia Background & Objectives: Presently, modern methods of electrosurgery are necessary for conducting surgeries, especially in emergency conditions, such as when tracheostomy is performed in patients with tumour laryngeal stenosis. The aim of the work was to compare the effects of radio-wave (RW) and molecular resonance (MR) surgery on rat neck skin regeneration. Methods: Cuts were made with a microsurgical RW generator (1group) and a MR generator (2group) on neck skin of 10 rat's. Cytological study of preparations obtained using the superficial biopsy method (May-Grünwald stain). Cytograms were determined for 5 types according to M.F.Kamaev. After surgery at 1,2,4,6,8,10&12 days rats were scored 2 from each group and a histological study of postoperative wounds (H&E, toluidine blue stain). In assessing morphological changes we evaluated necrosis,the severity of inflammatory changes, edema, proliferative changes, epithelization. Results: Cytological examination showed that from day 2 the number of neutrophils decreased in gr.1 (p<0.01), and from day 5 the number of fibroblasts increased, compared with gr.2 (p<0.005). In gr.1, the thickness of the necrosis is less than in gr.2 (87.5+8.1 against 112±6.5), from day 3, edema (p<0.005), the mast cells number (p<0.005) and neutrophilic infiltration of the wound edges were more in group 2 (p<0.005), proliferative changes and epithelialization were better in gr.1 (p<0.001). Conclusion: RW exposure is a more effective way of transforming electric energy in the vibration of tissue molecules, which allows to achieve the dissection at lower power output, as compared to the MR method. This studies have revealed that the inflammatory response and the healing time for wounds are significantly less after RW exposure compared to MR method. The publication has been prepared with the support of «RUDN University Program 5-100». PS-MD-01-006 Up-converting nanoparticles as a tool for histopathological tissue evaluation with multiplexing and machine learning potential K. Krawczyk 1 , S. Andersson-Engels 2 , A. Sjögren 1 1 Lumito AB, Sweden, 2 Biophotonics@Tyndall, Tyndall National Institute, Cork, Ireland Background & Objectives: In the field of histopathology, a risk for misdiagnosis is a serious issue. A standard way to visualise cell morphology is through H&E staining often combined with DAB chromogenic stain. However, this method suffers from narrow dynamic range, problems with quantitation and difficulties with multiplexing and co-localisation. Fluorescent IHC techniques generate a more quantitative readout but suffer from photobleaching. Here we present that the use of up-converting nanoparticles (UCNPs) allows to overcome problems associated with commonly used imaging techniques. Methods: Novel luminescent UCNPs were used together with a prototype instrument to image selected markers, e.g. Her2, in the human tissue. Formalin-fixed paraffin-embedded human colon and breast cancer tissues were sectioned and stained using autostainer. UCNP fluorescence imaging of the human tissue sections was compared with a standard DAB based IHC. Pulsed excitation and gated detection were explored to improve the scanning speed. UCNP and H&E co-staining and co-imaging were also investigated. Results: Images obtained with our novel device clearly show that developed by us antibody-UCNP conjugates can be used to successfully stain the human tissues. Brightfield images show that UCNPs are not visible in white light and hence do not interfere with standard tissue evaluation by a pathologist. Additionally, brightfield and luminescent images can be merged to provide better understanding of tissue morphology. Conclusion: Emerging field of UCNPs opens up new possibilities. Staining solutions and a novel device developed by us give hope for more accurate diagnosis by keeping the advantage of H&E staining and combining it, in one image, with luminescent data, ideal for generating ground truth for machine learning algorithms. PS-MD-01-007 Pathohistological characteristics of breast cancer in BRCA-positive and BRCA-negative women S. Ramic 1 , I. Kirac 1 , T. Oresic 1 , T. Zigman 1 , V. Musani 2 , P. Ozretic 2 , O. Vugrek 3 , I. Milas 1 1 Genetic Counseling Unit, University Hospital for Tumours, Sestre Milosrdnice University Hospital Center, Zagreb, Croatia, 2 Lab. for Hereditary Cancer, Div. of Molecular Medicine, Institute Rudjer Boskovic, Zagreb, Croatia, 3 Lab. for Advanced Genomics, Div. of Molecular Medicine, Institute Rudjer Boskovic, Zagreb, Croatia Background & Objectives: Our Hospital introduced Genetic counseling and testing for patients affected with breast/ovarian cancer or healthy individuals from hereditary breast and ovarian cancer families. BRCA1/2 gene testing was indicated in individuals who met the criteria according to the Clinical Practice Guidelines. Methods: BRCA1/2 germline mutations were analysed in whole blood samples using next-generation sequencing, Sanger sequencing and quantitative PCR methods. We compare pathohistological characteristics of breast cancer in BRCA-mutation carriers and non-carriers. Results: BRCA1/2 was tested in 153 women, and 20 of them carry germline BRCA1/2 mutation: 16 in the BRCA1 gene, 4 in BRCA2 gene and 3 had a BRCA2 variant of unknown significance. We collected data on 57 breast cancer patients, of which 12 were BRCA mutation carriers. BRCA-positive women with BC were younger at the time of diagnosis than women without BRCA mutations (median 38.5 years vs. 45.5 years). Among BRCA-positive patients, 75% had triple-negative breast cancer (TNBC), 16.7% had Luminal/HER2 positive BC and 8.3% with Luminal/HER2 negative BC. Among BRCA-negative patients, only 9.5% had TNBC, 66.7% had Luminal/HER2 negative BC, 16.7% had Luminal/HER2 positive and 7.1% had HER2 enriched BC. Patients with BRCA2 variant of unknown significance had Luminal/HER2 negative breast cancer. Although the average size of the tumour was larger in BRCA positive patients (25 mm vs. 18 mm), there is no difference in median size of the tumour (15mm). Conclusion: Detection of family members with germline BRCA1/2 mutations may play a vital role in breast cancer risk assessment and surveillance/treatment plan. PS-MD-01-008 Comparison of four microsatellite instability testing methods in endometrial cancer- reliability, handling, cost effectiveness J. Siemanowski 1,2 , B. Schömig-Markiefka 1,2 , W. Dietmaier 3,4 , N. Arens 5 , T. Buhl 1,2 , R. Büttner 6 , S. Merkelbach-Bruse 7 1 University Hospital Cologne, Germany, 2 Institute of Pathology, Germany, 3 University Regensburg, Germany, 4 Institute of Pathology, Germany, 5 Molecular Pathology Trier, Germany, 6 Institute for Pathology, Cologne, Germany, 7 Institute of Pathology University Hospital of Cologne, Germany Background & Objectives: Microsatellite instability (MSI) is a common alteration in endometrial cancers caused by aberrations in the DNA mismatch repair system and recently designated as a predictive biomarker for response to immune checkpoint therapy. Differences in MSI profiles between endometrial and colorectal cancers enable the possibility of false negative results in routine diagnostic. This study compares four different PCR based testing approaches initially designed for the detection of MSI in colorectal cancer. Methods: 25 endometrial tumours with immunohistochemically diagnosed stable, instable and uncertain microsatellite status were selected. Tumour and paired normal tissue DNA was extracted from formalin-fixed, paraffin-embedded (FFPE) material. MSI testing was performed by fragment length analysis with an in-house Bethesda-Panel and the MSI Analysis system (Promega) as well as parallel sequencing with a custom GeneRead V2 panel (Qiagen). 10 μm slices of the same FFPE tumour tissues were taken for the Idylla MSI assay (Biocartis). Results: All four methods showed a high overall concordance and could clarify uncertain MSI status due to inaccurate IHC. Analysis and interpretation of results was more time consuming with the Bethesda-, Promega-Panel and the parallel sequencing Approach. Conclusion: This study showed that all MSI testing methods provided reliable results for MSI testing albeit dealing with difficulties during interpretation of results. The Idylla MSI assay seems to be a suitable alternative to the other assays due to easy result interpretation and cost effectiveness caused by short hands on time without the need of normal tissue. PS-MD-01-009 Association between KRAS, NRAS, BRAF mutation status and clinicopathological prognostic factors in colorectal carcinoma in Turkish population D. Unal Kocabey 1 , E. Cakir 1 , F.H. Dilek 1 , B. Bolat Kucukzeybek 1 , A. Calli 2 1 Izmir Katip Celebi University Ataturk Training and Research Hospital Department of Pathology, Turkey, 3 Dokuz Eylul University Molecular Medicine, Turkey Background & Objectives: KRAS , NRAS and BRAF mutations have prognostic and predictive value in colorectal carcinoma (CRC). The aim of this study is to investigate frequency of KRAS , NRAS , BRAF mutations in Turkish CRC patients and to evaluate their relationship with clinicopathological prognostic factors. Methods: All CRC patients who underwent surgical resection from 2008 to 2018 and tested for KRAS , NRAS , BRAF mutation at our Institution were analysed retrospectively. The association between KRAS , NRAS, BRAF mutation status and clinicopathological prognostic factors including age, sex, tumour site, tumour size, histological grade, pT stage, pN stage, lymphovascular invasion, perineural invasion, tumour deposit were compared statistically. Results: A total of 137 patients with CRC were retrieved. KRAS , NRAS and BRAF mutations were detected in 34.6% (47/136), 13.2% (12/91) and 3.6% (2/56) of tumours, respectively. We identified KRAS mutations in codon 12, 13, 59 and 146 in 70.2% (33/47), 21.3% (10/47), 6.4% (3/47) and 2.1% (1/47), respectively. Also, we found NRAS mutations in codon 12, 61, 13, 59 in 41.7% (5/12), 25% (3/12), 16.7% (2/12), 16.7% (2/12), respectively. While absence of KRAS mutation was significantly associated with perineural invasion (P = 0.002), there was no significant association between KRAS mutation status and other clinicopathological features. Similarly, there was no significant association between NRAS and BRAF mutation status and clinicopathological features. Conclusion: The effect of KRAS , NRAS and BRAF mutations on clinicopathological features is unclear. Future studies with larger patient groups can help to clarify the association between KRAS , NRAS , BRAF mutations and clinicopathological features. PS-MD-01-010 Results of the Belgian ring trial for liquid biopsy testing in non-small cell lung cancer show variety in the interpretation of the test result K. Van Casteren 1 , K. Dufraing 1 , P. Pauwels 2 , N. D'Haene 3 , E. Dequeker 1 1 Biomedical Quality Assurance Research Unit, KU Leuven, Leuven, Belgium, 2 Laboratory of Pathological Anatomy, Antwerp University Hospital, Edegem, Belgium, 3 Department of Pathology, Erasme University Hospital, Brussels, Belgium Background & Objectives: The use of liquid biopsies for detecting resistance mutations after disease progression in patients with non-small cell lung cancer has been introduced into routine. This study aimed to evaluate how well laboratories interpret and report test results. Methods: Laboratories participating in the Belgian EGFR ctDNA Ring Trial 2018 (N=17) received 3 mock requests and test results from fictional patients for which they had to submit reports resembling their daily routine. Reports were assessed based on pre-defined scoring criteria. Marks were given for the test result (0.75), clinical interpretation (0.625), patient name (1.00), date of birth (1.00), the assay used (0.125), targeted aberrations (0.25) and the reference sequence (0.25). For other items only individual feedback was given. Results: The average reporting score was 3.12/4 (N=17) based on the presence of 7 elements. Interpretations received average scores of 67%, 50% and 44% for cases 1, 2 and 3, respectively. In case 3, a resistance mutation was detected but not the activating mutation because not targeted by the test method. The latter was recommended to be clearly stated in the interpretation. Elements like the sampling date (59%), reason for testing (59%), DNA extraction method (47%), method sensitivity (53%) and reference sequence (18%) were only present on a limited number of reports. Conclusion: This ring trial showed that there is still room for improvement regarding reporting molecular pathology results. As liquid biopsy testing has only recently entered daily practice, a clear and correct report might further educate prescribing oncologists. Further initiatives on improvement are currently being set-up. K. van Casteren and K. Dufraing are first authors in equal proportions. The research project was funded by a grant from N.V. AstraZeneca S.A. PS-MD-01-011 Establishment of a 3D histopathology platform for precision tumour diagnosis J. Yang 1 , Y. Lin 2,3 , A. Chiang 2,4 , I. Wang 5 , S. Wu 6 , M.D. Chang 7 , J. Lee 8 , J. Ko 9 , S. Liang 9 , J. Guo 10 , X. Song 10 , H. Huang 10 , M. Chao 11 , C. Lin 12 1 Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan, 2 Brain Research Center, NTHU, Taiwan, 3 JelloX Biotech, Hsinchu, Taiwan, 4 Institute of Systems Neuroscience, NTHU, Taiwan, 5 Institute of Biotechnology, NTHU, Taiwan, 6 Department of Engineering and System Science, NTHU, Taiwan, 7 Institute of Molecular and Cellular Biology, NTHU, Taiwan, 8 Oncology Department, National Taiwan University Hospital Hsin-Chu Branch, Taiwan, 9 Internal Medicine Department, National Taiwan University Hospital Hsin-Chu Branch, Taiwan, 10 Pathology Department, National Taiwan University Hospital Hsin-Chu Branch, Taiwan, 11 Surgery Department, National Taiwan University Hospital Hsin-Chu Branch, Taiwan, 12 Oncology Department, National Taiwan University Hospital, Taipei, Taiwan Background & Objectives: Rapid and accurate evaluation of full picture of histopathological biopsy has clinic unmet need. We thus aim to establish an automated 3D histopathology platform that emerges comprehensive pathologic images in support of quantitative data analyses and standardised digital format to overcome technology limitation of current 2D image diagnosis tools. Methods: The platform offers an innovative optical tissue clearing immersion system with high-resolution of 3D image technology, employing alternative scanning and slicing processes reliable depth control of continuous automatic images and digital suture parallel multi-stack images, and thus panoramic 3D digital images of a complete histopathological sample are produced. Results: The platform allows detection in-depth and comparative analysis of normal and pathological organization. Moreover, our innovative database stores high resolution images of deep tissues that are suitable for building up artificial intelligence algorithms. The 3D-AI assisted pathological modules in detecting malignant cancer cells in mouse lung cancer model and in clinical metastatic breast to lymph nodes model will be demonstrated in ECP 2019. Conclusion: Our automated 3D histopathology platform could provide intact deep tissue histopathological database for practical application of AI auxiliary precision medicine. Supported by MOST106-3114-8-007-001, Ministry of Science and Technology, Taiwan.

Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-01 | Autopsy Pathology Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-01 | Autopsy Pathology E-PS-01-001 Pulmonary fibrosis as a manifestation of connective tissue disease E. Malysheva 1 , S. Timofeev 1 , E. Startseva 1 , N. Zharkov 1 1 City Hospital of Moscow, Russia Background & Objectives: Pulmonary fibrosis is a complex issue, so much so that determining the true causes of this disease has been a stumbling block for pulmonologists and pathologists for many years. More recently, however, our understanding of pulmonary fibrosis has developed to such an extent that researchers have discovered that there are similarities between patients with pulmonary fibrosis and those with a connective tissue disease. Methods: A 48-year-old woman was admitted to hospital and diagnosed with pneumonia. Her medical history informed us of childhood asthenia and hypermobility of the joints. Despite treatment, her condition worsened and she died. The cause of death was pulmonary heart disease. The autopsy revealed deformation of the chest, sometimes seen in patients who suffer from a connective tissue disease. Lungs had pleural and perivascular fibrosis. The lumen of the alveoli had a mixture of desquamated epithelium with macrophages and hyaline membranes. Results: Epithelium cells of the alveolar lining and stroma cells had a positive reaction with plasminogen activator inhibitor type 1 (PAI-1), “dot like” cytoplasmic staining. Stroma cells, perivascular spaces and walls of blood vessels were markedly positive with antibodies to type IV collagen and positive with CD117 / c-kit. The lumen of the alveoli and the interstitial spaces had a significant amount of HLA-DR and CD68-positive cells, which formed clusters in the cavity of the alveoli. Conclusion: Despite the patient suffering from symptoms related to connective tissue disease, including weight loss, chest deformation and hypermobility of the joints, the main manifestation of the disease was actually pulmonary fibrosis. E-PS-01-002 Incidental adrenal tumours in forensics C. Amalinei 1 , L. Lozneanu 1 , B. Ioan 1,2 , L. Riscanu 1,2 , A. Grigoras 3 1 "Grigore T. Popa" University of Medicine and Pharmacy Iasi, Romania, 2 Institute of Legal Medicine Iasi, Romania, 3 Department of Morphofunctional Sciences I-Histology, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi, Romania Background & Objectives: Adrenal masses are rare, incidental findings in forensic pathology. The aim of our study is to report the particular features of four cases, occurred in 50-69 years old subjects, two females and two males. Methods: Routine hematoxylin-eosin, along with immunohistochemistry using synatophysin, chromogranin, S100, MelanA, and inhibin, in two selected cases, have been performed. Results: Gross findings were variable. Microscopy revealed, in two cases, circumscribed areas of alveolar growth pattern and cytologic vacuolar degeneration, synaptophysin+, chromogranin+, S100+ (focal), MelanA-, and inhibin-, characteristics of pheocromocytoma. One of them had vascular invasion, and multiple tumoural implants, being diagnosed as metastatic malignant pheocromocytoma. In another case, islands of metastatic implants of a lung adenocarcinoma have been detected. In the last case, an adrenal nodule with alveolar growth pattern of slightly enlarged cells was diagnosed as a cortical adenoma. Conclusion: Although rare in necropsy, adrenal masses should be investigated as they may reveal potential severe diseases and tanathogenesis significance. Immunohistochemistry may be useful to discriminate specific types of tumours, in correlation with the clinical information, gross findings, and microscopic features in routine staining. E-PS-01-003 Secondary meningo-cerebral tumours with unknown lung primaries - necroptic features C. Amalinei 1 , A. Grigoras 2 , C. Teodorescu 3 , L. Riscanu 1,3 , L. Lozneanu 1 1 "Grigore T. Popa" University of Medicine and Pharmacy Iasi, Romania, 2 Department of Morphofunctional Sciences I-Histology, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi, Romania, 3 Institute of Legal Medicine Iasi, Romania Background & Objectives: Most common central nervous system tumours represent metastases and the primary tumour has usually been already diagnosed. Metastases of unknown primaries may be discovered in forensic pathology. The aim of our study is to report the particular features in eight cases of meningo-cerebral metastases diagnosed during the last three years, in our Department, in subjects with age range between 55 and 80 years old, five men and three women. Methods: Routine hematoxylin-eosin and Masson’s trichrome staining, along with immunohistochemistry using a panel of markers (CK7, TTF1, CK5, p63, AE1/AE3, CK20, and HepPar1) have been performed. Results: Gross appearance was that of sharply delimited lesions, mainly disposed at the gray-white matter junction, of 1-2 cm diameter, containing variable necrosis and haemorrhage. Microscopy revealed multiple lesions with variable location: cerebrum, brainstem, cerebellum, meninges, along with meningeal carcinomatosis (in three cases). Liver metastases have been also found in two cases and have been excluded in a case with an ectopic adrenal gland. The primary tumours have been identified as seven cases of lung adenocarcinomas and one squamous cell carcinoma. Conclusion: Metastases of lung carcinomas have to be considered in meningo-cerebral malignancies. Differentials should include primary meningo-cerebral tumours and the final diagnosis has to be certified by corroboration of comparative size between primaries and secondaries, characteristic multiple, secondary lesions, including the possibility of additional liver metastases, along with specific expression of immunohistochemical markers and microscopic features. E-PS-01-004 Post-mortem diagnosis of metastatic male breast cancer with fulminant evolution D. I. Enea 1 , M. Ceausu 2 , A. Tita 2 , G. Roman 2 , M. Bosa 2 , L. Luca 2 , O. Neagu 1 , L. Tomescu 1 1 University Emergency Hospital, Bucharest, Romania, 2 "Mina Minovici" National Institute of Legal Medicine, Bucharest, Romania Background & Objectives: Male breast cancer is a rare form of malignancy which develops from the small amount of residual breast tissue found in men. It usually affects older men with a background of hormonal imbalances, but the risk factors are not entirely known. Methods: This report describes an unusual case of breast cancer in a 60-year-old man with obesity and vertebral algic symptoms. MRI exam highlighted multiple lytic lesions of the spine, including T12-L2 pathological fractures. Subsequent clinical examination revealed a left breast mass. Due to rapid deterioration of the patient’s condition, followed by exitus (<1 month), any further investigations couldn’t be performed and the diagnosis remained uncertain. The autopsy detected cirrhosis, a left breast tumour and metastasis in the spine. Results: Microscopically, there was an invasive carcinomatous proliferation composed of pleomorphic cells arranged in nests, trabeculae, cords, with desmoplastic stroma, located in the breast, lungs and liver. By means of immunohistochemistry, the tumour cells showed positive reaction for AE1-AE3, ER (~ 1-5 %) and a high proliferation rate (PCNA ~ 80-90%). The histopathological findings suggested a poorly differentiated, highly aggressive, invasive ductal carcinoma of no special type (NST) of the breast with liver, lung and bone metastasis. Conclusion: The particularity of this unusual case resides in rapid evolution of an aggressive, metastatic, male breast cancer, with a high rate of proliferation, on a background of a delayed diagnosis due to a misleading tumour appearance, in the context of hormonal imbalance caused by cirrhosis and obesity. E-PS-01-005 Multi-organic infiltration by anaplastic large celllymphoma, ALK positive, diagnosed in autopsy A. M. G. Pereira 1 , F. Galante Pereira 1 , C. A. Padrão 1 , A. T. Alves 2 1 Hospital Prof. Doutor Fernando Fonseca, EPE, Portugal, 2 Instituto de Anatomia Patológica da Faculdade Medicina Universidade de Lisboa, Portugal Background & Objectives: ALK-positive (ALK+) anaplastic large cell lymphoma (ALCL) is a T-cell lymphoma that accounts for approximately 3% of adult non-Hodgkin lymphomas and frequently involves both lymph nodes and extranodal sites, most commonly the skin, bone, soft tissue, lungs, and liver. Methods: Diagnosing lymphoma is not easy, and the clinical presentation of this 64 years old man we are presenting was challenging and misleading with high fever, heterogeneous hepatomegaly and diarrhea. Clinical presentation suggested an infectious disease and a possible consumptive process supported by a story of weight loss. Empiric antibiotic therapy was started and the CT-scan report found multiple adenomegalies and hepatomegaly with areas of nodular hipocaptation suggestive of small abscesses. Blood tests also revealed acute renal and liver failure. Results: With rapidly progressive health deterioration, the man died after three days and, without a definitive diagnosis, an autopsy was requested. An extensive infiltration by ALK+ ALCL was documented, involving all the lymph nodes that were observed plus the liver, lung, bone marrow, spleen, kidneys, adrenal glands and the myocardium. Conclusion: We present this case to highlight how even an extensive and advanced stage ALCL can “fly under the radar” and involve some less common and rare extranodal sites. E-PS-01-006 Anaplastic Carcinoma Thyroid in a cervical trauma: an autopsy report J. Melo 1 , E. Ribeiro de Lemos 2 , M.C. Carneiro da Ibiapaba 2 , T. Guimaraes do Nascimento 2 , L. Camelo Oliveira 2 , L. Macedo Pinto 2 , D. Nunes Oliveira 1 , D. Nunes de Melo 3 1 Department of Pathology, Postgraduate Program in Public Health, Faculty of Medicine, University of Fortaleza, Brazil, 2 Faculty of Medicine, University of Fortaleza, Brazil, 3 State Secretary of Health, Brazil Background & Objectives: Anaplastic thyroid carcinoma (ATC) is one of the most aggressive cancers Report a case of Anaplastic thyroid cancer which symptoms were triggered after a car accident. Methods: Autopsy was made in Legal Medical Institute. Male, 51 years old, victim from a car accident three months ago suffered a anterior cervical trauma steering wheel injury. A few days later, he evolved with a bulky anterior cervical mass, hoarseness, an obstructive respiratory insufficiency and was submitted to an urgent tracheostomy. After, there was a food leakage from the tracheostomy, so it was put a nasoenteral tube. He evolved with dyspnea, bulky tracheostomy bleeding and death. Results: Macroscopy: a surgical specimen measuring 10x8x7cm where we identified proximal portion of the trachea, larynx, thyroid and related structures, compromised by tumour lesion of ill defined, grayish and friable limits. Microscopy, an undifferentiated malignant neoplasm with pleomorphic giant cells, parts of them fusiform, with sarcomatous aspect, presenting vesiculous nucleus with macronucleolus, many bizarre mitosis figures, extensive areas of necrosis and hemorrhagic focus. Tumour cells are arranged in solid blocks and infiltrate widely the thyroid parenchyma, skeletal muscle adjacent, larynx and trachea, which causes complete luminal obstruction. Also compromises angiolymphatic structures and perineural spaces adjacent. Conclusion: The case shows a rare episode of anaplastic thyroid cancer in which the symptoms appeared after a trauma. Therefore, it is necessary a fast identification and establishment of a effective therapeutic, looking after a better care for the patient. E-PS-01-007 Giant intraventricular thrombi as a complication of chronic abuse of cocaine-levamisole K. Metze 1 , N. Biagioni de Lima 1 , R. Lanaro 1 , C.A. de Lima 1 1 State University of Campinas, Brazil Background & Objectives: Giant intraventricular thrombi in the heart are a rare phenomenon. They can be caused by different conditions such as antiphospholipid syndrome, heparin-induced thrombocytopenia, malignant neoplasias, Takotsubo cardiomyopathy, hypereosinophilic syndrome or aluminium phosphide poisoning. An important pathophysiological mechanism for many different conditions seems to be an endothelial dysfunction. The aim of this case report was to show that chronic cocaine-levamisole abuse can also cause giant ventricular thrombi. Methods: A 44-year old man with a history of chronic cocaine abuse was admitted to hospital with necrosis of the toes. Angiography revealed multiple arterial and venous thrombi in both legs and pulmonary thromboemebolism. Echocardiography suggested biventricular giant thrombi of the heart. Although submitted to anticoagulation treatment with heparin and symptomatic therapy, the patient evolved to hemodynamic instability and expired on the sixth day. An autopsy was performed. Results: Autopsy revealed widespread veonous thrombosis in both legs, recurrent pulmonary thrombembolism with infarcts and giant thrombi in both cardiac ventricles as well as gangrene of the distal parts of all fingers and toes due to thrombotic arteritis. Toxicologic hair analysis showed chronic abuse of cocaine mixed with levamisole for at least 6 months. Conclusion: Levamisole, an antihelminth and immunomodulatory adjuvant, is an adulterant in cocaine worldwide. Widespread venous thrombosis and thrombotic arteritis suggest generalized endothelial dysfunction as the leading pathophysiological mechanism which might also eplain the genesis of the giant thrombi. In summary, we describe cocoaine–levamisole intoxication as a new predisposing condition for intracardiac giant thrombi most probably related to a generalized endothelial dysfunction. Supported by CNPq Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-02 | Breast Pathology Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-02 | Breast Pathology E-PS-02-001 Squamous cell carcinoma of the breast with apocrine features: a rare variant of metaplastic breast cancer C. Taverna 1 , A.G. Naccarato 2 , C. Scatena 3 1 Division of Pathological Anatomy, Department of Health Sciences University of Florence School of Human Health Sciences Florence, Italy, 2 University of Pisa, Italy, 3 Division of Pathology, Department of Translational Research and of New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy Background & Objectives: Small-cell neuroendocrine carcinoma of lung is one of the most frequent types within endobronchial biopsies. Although it shows characteristic histopathological finding, immunohistochemistry is necessary in many cases due to the variety of possible differential diagnoses. The expression of the different markers usually employed as CKAE-1AE3, TTF-1 and neuroendocrine markers varies according to the literature. In particular, it is very important to know that these neoplasms can show negative immunostain for epithelial markers and even for TTF-1. Methods: The archive were reviewed between the years 2009-2014, obtaining 110 cases. There were 97 mens and 13 women.The median age was 72 ( range betwen 41 to 90 year old). We studied 78 biopsies and we also included 32 cases of lung FNA. Results: From 110 cases we found 7.27% that were negative for TTF1 immunostain, 1.8% with negative immunostain for CKAE1-AE3. The rest of performed neuroendocrine markers were chromogranin, synaptophysin and CD56, which were negative in 11.92%, 22% and 2.75% respectively. Conclusion: There are few bibliographical references to the percentage of negativity for TTF1 and CKAE1-AE3 in this tumour. The negativity for CKAE1-AE3 and TTF-1 is considered extremely rare. This study contributes important information, since it characterises immunoprofile of small-cell carcinoma. This information is useful in cases that show a usual morphology of small cell neuroendocrine carcinoma but with unusual immunohistochemical expression. E-PS-02-002 Sebaceous carcinoma of the breast in a male patient with a BRCA2 germline mutation: case report and literature review J. Lobo 1 , P. Lopes 1 , R. Henrique 1 , î Rodrigues 1 1 IPO Porto, Portugal Background & Objectives: Sebaceous carcinoma (SC) is an overall uncommon neoplasm. Its occurrence on the breast is very rare. We aim to present a case of primary SC of the male breast in the context of a BRCA2 mutation. Methods: A 79-year-old man complained of a breast lump detected on self-examination. Core-biopsy reported “grade 2 invasive carcinoma with secretory pattern”. He was referred to our Institution and underwent left total mastectomy was performed. Macroscopically, a hard, well-circumscribed and lobulated, yellowish, 1.9cm nodule was depicted. It was centered in breast parenchyma and the overlying skin/nipple-areolar complex were unremarkable. Results: Histologically, it corresponded to an invasive carcinoma, with nested architecture and no evidence of cutaneous origin. >80% of the tumour displayed large clear cells, with microvacuolated cytoplasm, admixed with smaller basophilic cells. Intraductal carcinoma with same features was present. It was diffusely positive for ER/PR/AR/EMA, and negative for HER2/GCDFP15. A diagnosis of SC of the breast was made. The patient’s daughter had been diagnosed with breast cancer at age 44 and the patient was found to carry a BRCA2 mutation. Conclusion: Compliance with strict criteria proposed in WHO 2012 is necessary for clearly discriminating this entity from breast cancer with sebaceous differentiation and from SC of the overlying sebaceous glands. This is the first case of SC of the breast in a male patient with a germline BRCA2 mutation. PhD Grant by FCT (grant number SFRH/BD/132751/2017). E-PS-02-004 Case report: a 56-year-old woman with primary neuroendocrine carcinoma of the breast M. Dieaconu 1 , D. Ferariu 2 1 Regional Institute of Oncology, Iasi. Romania, 2 Department of Pathology, Regional Institute of Oncology, Iasi, Romania Background & Objectives: Primary neuroendocrine carcinomas of the breast represent a rare entity, with incidence under 0.1% from all breast carcinomas and under 1% from all neuroendrocrine carcinomas. We present the case of an 56-year-old woman with a single solid nodule in the right breast, admitted to the surgical oncology department of Regional Institute of Oncology Iasi, Romania. Five days prior to the admission the lesion was discovered during a routine screening mammogram. The patient has no significant past medical history. Methods: The routine screening mammogram revealed a well circumscribed homogeneous nodule of 12/10 mm situated in the lower inner quadrant of the right breast, considered low-risk. No additional abnormalities were found. It was performed a core-biopsy, and two fragments of tissue of 7 and 4 mm were fixed with formalin 10%, paraffin embedded and analysed using hematoxylin and eosin staining and immunohystochimical tests. Results: Microscopy revealed uniform small cells separated by delicate fibrovascular stroma. Tumour cells have round nuclei with granular chromatin, scant cytoplasm, mitosis and apoptosis. Cells were positive for synaptophysin, chromogranin and TTF-1, negative for estrogen and progesterone receptors. HER2neu was 0 (negative). After immunohistochemical analysis the differential diagnosis was made with a metastasis from another primary neuroendocrine tumour. PET/CT and abdominal ultrasound excluded a non-mammary primary site. The patient received chemotherapy and radiotherapy. Conclusion: Primary neuroendocrine carcinoma of the breasts is a rare tumour, classified as a type of invasive mammary carcinoma with distinctive histopathological features. It exhibits morphological features similar to those of neuroendocrine tumours of the gastrointestinal tract and the lung, therefore it is crucial to make an accurate diagnosis and first exclude a metastasis in the breast. E-PS-02-005 Low grade breast adenosquamous carcinoma: a clinicopathological and genetic study R. Ondruššek 1 1 CGB laboratory a.s., Czech Republic Background & Objectives: Low grade adenosquamous carcinoma (ASC) of the breast is an unusual and rare variant of metaplastic triple-negative carcinoma with excellent prognosis. Tumour is characterised by small well-developed glandular formations intimately admixed with solid nests of squamous cells in a spindle-cell background. Triple negative carcinomas are included in heterogenous group of tumours with therapeutic limitations. Specific changes in several genes can help to offer targeted therapy. Methods: In 2018 we diagnosed mammary ASC in three female patients in the segmentectomy specimens. We evaluated clinical data, pathological features and genetic profiling retrospectively. TP53, EGFR, PTEN, CDKN2A genes were investigated by fluorescence in situ hybridization (FISH). Results: The median age of patients was 74 years (ranging from 70 to 79), tumour diameters 0.2 – 2.7cm, TNM stage pT1a - pT2. Sentinel lymphatic nodes were available for their evaluation in 2 out of 3 patients and no metastases were found. FISH did not demonstrate amplification EGFR gene (7p11), deletion PTEN gene (10q23), deletion TP53 gene (17p13) deletion CDKN2A gene (9p21). All cases showed typical histopathological features of low grade ASC with conspicuous stromal lymphocytic aggregates. Conclusion: This study confirms excellent prognosis of ASC of the breast without sentinel lymphatic nodes involvement and where available genetic testing turns out to be negative. We suggest that lymphocytic aggregates might be useful and significant morphological feature to improve diagnosis in breast low grade ASC. E-PS-02-006 Breast adenomyoepithelioma: potential pitfalls in the diagnosis S. Aviel-Ronen 1 , J. Simon 2 , M. Papa 3 , G. Gitstein 4 1 Department of Pathology, Sheba Medical Center, Tel-Hashomer, Israel, 2 Institute of Diagnostic Radiology, Meuhedet Health Maintenance Organization, Rehovot, Israel, 3 Surgery Department, Assuta Medical Center, Tel Aviv, Israel, 4 Pathology Department, Sourasky Medical Center, Tel Aviv, Israel Background & Objectives: Adenomyoepithelioma of breast is a rare benign tumour of the epithelial-myoepithelial group of lesions. This tumour is characterised by proliferation of myoepithelial cells surrounding small epithelium-lined spaces. Here we describe a case of adenomyoepithelioma and discuss the potential pitfalls in the diagnosis. Methods: The medical records, imaging tests and pathological findings of a 64 patient have been studied and are presented. A suspicious left breast semi-cystic lesion, 1 cm in diameter, was identified on screening mammography. The core needle biopsy that was performed showed unusual and non-conclusive histological characteristics, therefore a complete excision of the lesion was advised. Subsequently, lumpectomy was performed. Results: On lumpectomy, a cellular multi-lobulated lesion was identified. The lesion showed proliferation of bland spindle cells occasionally surrounding gland-like structures. Neither nuclear atypia nor mitotic activity were identified. Many myoepithelial cell markers including p63, calponin, caldesmon, podoplanin and CD10 were negative. However, CK 5/6, S100 and SMA stained diffusely the tumour cells, while ER stain highlighted the epithelium-lined spaces. In spite of the partly contradicting immunostain results, it was concluded that the lesion is a benign adenomyoepithelioma. Conclusion: Myoepithelial cells show diverse appearance with their various immunostain markers and demonstrate differences in their staining sensitivity in different lesions. Therefore, it is crucial to use a broad panel approach and address the morphological features in order to reach an accurate interpretation of epithelial-myoepithelial lesions. E-PS-02-007 Prognostic value of proliferation marker assessments in patients with different biological subtypes of breast cancer L. Rudiuk 1,2 , O. Reshetnikova 3 , S. Korenev 1 1 Immanuel Kant Baltic Federal University, Kaliningrad, Russia, 2 Regional Clinical Hospital of the Kaliningrad region, Kaliningrad, Russia, 3 Immanuel Kant Baltic Federal University, Russia Background & Objectives: Breast cancer (BC) is the most common cancer and the second leading cause of cancer-related death among women. BC remains an important health issue worldwide. The aim of this study was to correlate tissue expression of proliferation biomarker Ki-67 with different immunohistochemical (IHC) subtypes of breast cancer and to assess the relationship of Ki-67 to tumours histological grading. Methods: This was a retrospective study including 220 female patients with breast cancer. The histological diagnosis was performed on formalin-fixed and paraffin-embedded breast tissue blocks from pretreatment biopsies and mastectomies. Tumour grading was determined according to Elston&Ellis. IHC analyses were carried out with the help of following monoclonal mouse antibodies: to ER (RTU, Bond 6F11), PgR (RTU, Bond 16), HER2 (Novocastra, CB11 1: 250). Ki67 expression was tested with monoclonal mouse antibodies (RTU, MM1) and then proliferation activity was determined as a percentage of the stained parenchymal component of an invasive breast carcinoma of a no special type (in 10 microscopic fields of view per 1000 cells at magnification x400). Relation between the tumour grade and proliferative activity in biological subgroups of the BC were assessed by Spearman's rank correlation coefficient. High correlation between the two variables got rank 1 (r=1). Results: Molecular subgroups of the BC cases were distributed as follows: luminal A -45.91%; luminal B HER2- positive - 25.46%; luminal B HER2- negative -18.64%; triple negative-18.18%; HER2- positive -10%.The majority of cancer samples had histological grade (G) 2, to a lesser extent G1 and G3 were recognized. Luminal B group, both positive and negative, a statistically significant positive correlation was established between the indicators (Spearman correlation coefficient: 0.410521 and 0.403631, respectively). Luminal B group, both positive and negative, had a high correlation between G and Ki67 expression (Spearman correlation coefficient: 0.410521 and 0.403631, respectively). Other molecular subgroups of the BC had a low correlation between mentioned variables. Conclusion: In order to assess the biological aggressiveness of a breast cancer, a further IHC study of apoptosis and intercellular adhesion needed. E-PS-02-008 Maligant phyllodes tumour cum CDIS: case report W. Michej 1 , W. Olszewski 2 , J. Owczarek 2 1 Cancer Centre Instytute Warsaw, Poland, 2 Cancer Centre Instytute, Poland Background & Objectives: Malignant phyllodes tumour is a rare case end develops in older women. The recognition demands macroscopic, microscopic end immunuhistochemical description. The characteristic whorled pattern, curved clefts is seen in the most lesions. Histologically - a combination of marked nuclear plemorphism of stromal cells, mitotic activity, permeative margins. The aim of this case report is to highlight characteristic details to make a good recogniction of phyllodes tumour and differentiate from metaplastic carcinoma. It is important for futher treatment after surgical removing. Methods: A 50 years old woman was operated due to 3,0cm tumour of breast. Grossly well defined, grey tumour was revealed. H-E examination showed many pleomorphic cells, necrosis and unregular mitotic figures. Between such pictures the structures of CDIS NG1 were also present. The question was: is it a malignant phyllodes tumour with CDIS or metaplastic carcinoma? Many of immunohistochemical reactions were done. The final diagnosis was - malignant phyllodes tumour (pleomorphic sarcoma) with CDIS low grade. Results: The woman was observed in our institute. After two years she developed a small lump in the same breast. Histologically it had only a pattern of pleomorphic sarcoma identical to the primary tumour. The component of CDIS was absent. It confirmed our diagnosis that it was a malignant phyllodes tumour. Conclusion: This case shows the possibility of coexistence of malignant transformations two components in phyllodes tumour. It is important to make a good diagnosis because of futher treatment. The recogniction of metaplastic carcinoma implicates more aggresive treatment after surgery i.e. chemotherapy. After diagnosis of malignant phyllodes tumour with CDIS low grade, excision within healthy limits until recurrence is recommended. E-PS-02-010 Interobserver agreement between pathologists assessing tumour-infiltrating lymphocytes in breast cancer by applying international TILs Working Group recommendations R. Ayadi 1 , D. Bacha 2 , O. Belkacem 2 , R. Yaiche 2 , A. Ben Amor 3 , S. Gharbi 2 , A. Lahmar 2 , S. Bouraoui 2 1 Pathology Department, Military Hospital, Tunis, Tunisia. University of Tunis El Manar, Faculty of Medicine of Tunis, Tunisia, 2 Pathology department, Mongi Slim Hospital, University Tunis El Manar, Medicine Faculty of Tunis, Tunisia, 3 Department of Gynaecology-Obstetrics, Mongi Slim Hospital, University Tunis El Manar, Medicine Faculty of Tunis, Tunisia Background & Objectives: Several studies highlighted the prognostic and predictive values of tumour-infiltrating lymphocytes (TILs) in breast cancer (BC). The aim of this study was to determine interobserver agreement between pathologists using the International TILs Working Group recommendations for the assessment of stromal TILs (sTILs) in BC. Methods: We retrospectively analysed 53 hematoxylin and eosin stained slides of invasive BC, obtained from 26 core needle biopsies and 27 surgical resections. Three pathologists independently reviewed each slide and evaluated sTILs. We used Fleiss’s kappa statistics to calculate the overall proportion of interobserver agreement. Results: The average age was56.5 years.The kappa statistic for sTILs assessment was 0, 55 with15 discrepancies cases.Discordances were mostly noted in surgical resection specimens (37%) compared to micro-biopsies (19%) and interested mainlyTILs proportions in intervals (5-10%) and (40-50%).Discrepancies reasons included the difficult distinction between carcinomatous cells and lymphocytes or granulocytes.In all samples, there has been a tendency to increasingTILs average rates in the presence of a focal hot spot zone.Artefactual retraction spaces helped to distinguish carcinomatous clusters from stromal inflammatory infiltrate. Conclusion: Acceptable agreement in sTILs assessment was noted when applying the international TILs Working Group recommendations. Sample fixation quality, which is better in micro-biopsies specimen, and a suitable contrasting staining, play an important role in the distinction between cell types. E-PS-02-011 Comparative evaluation of immunological micro-environment in the study of trepanobiopsy specimens and operational material of invasive breast carcinoma A. Semenova 1 , O. Isaeva 1 , A. Vagenin 1 , M. Bogatyreva 1 1 Chelyabinsk Oncology Clinic, Russia Background & Objectives: To assess differences in the representation of lymphocyte subpopulations in the biopsy and surgical specimens of breast carcinomas by routine morphological diagnostics; to determine by means of immunohistochemistry if the amount of tissue material is adequate for a reliable study of tumour-filtering lymphocytes (TILs) in breast carcinoma. Methods: The object of the study was trepanobiopsy specimens and surgical material taken from 60 patients with breast carcinoma with malignancy of various degrees (from G1 to G3). In the surgical material, the central zone of the tumour and the zone of active tumour growth (peritumoural) were evaluated and compared with the biopsy specimen (one tissue sample was taken). Subpopulations of T and B lymphocytes were investigated immunohistochemically using CD4 (Clone 4B12) (Dako), CD8 (Clone SP57) (Ventana), CD56 (Clone 123С3) (Ventana). Results: The study showed that regardless of the tumour malignancy degree, a significantly smaller number of CD4 positive T-lymphocytes and CD56 positive natural killer cells was observed in the surgical material and biopsy specimens taken from central and peritumoural zones of breast carcinomas. The representation of CD8 positive T-cytotoxic lymphocytes in all studied groups was comparably identical both in the biopsy specimens and in the surgical material, regardless of tumour malignancy degree. Conclusion: To assess the representation of CD8 positive T-cytotoxic lymphocytes in breast carcinomas, one standard core biopsy specimen is sufficient, regardless of tumour malignancy degree. To assess the infiltration of CD4, CD56 by positive breast carcinoma lymphocytes correctly, comparable to the surgical material, more samples are required, one specimen is not enough. E-PS-02-012 Primary leiomyosarcoma of the breast: a rare case report P. Tziakou 1 , V. Papamichail 2 , E. Delliou 3 , A. Zizi-Sermpetzoglou 1 1 Department of Pathology of Tzaneio General Hospital of Piraeus, Greece, 2 Laboratory of Pathology "ISTODOMI" - Piraeus, Greece, 3 Laboratory of Pathology - Xanthi, Greece Background & Objectives: Malignant mesenchymal tumours of the breast, other than angiosarcomas, are rare and comprise <0,5% of breast tumours. Primary leiomyosarcoma of the breast is an extremely rare tumour with <40 cases reported till date. We present a case of primary leiomyosarcoma of the breast. Methods: A 55-year-old female presented to our hospital complaining for pain with a large lump in her left breast for the last 6 months. Mammography and ultrasonography revealed a well-circumscribed tumour measuring 9x7cm in size, located in the upper quadrant of the left breast. FNA revealed evidence of malignancy and the patient underwent total mastectomy of the left breast and axillary lymph node dissection. Results: Microcopically, the tumour was composed of pleomorphic spindle cells arranged in intersecting fascicles and bundles, showing frequent mitoses and necrosis. On immunohistochemistry the tumour cells were positive for SMA and desmin and negative for S100p and CD117. Based on the immunomorphological features, the tumour was diagnosed as leiomyosarcoma. Conclusion: Leiomyosarcoma of the breast may originate from the smooth muscle of the lactiferous ducts of the nipple and the surrounding blood vessels. Differential diagnosis includes leiomyoma, spindle cell myoepithelioma and spindle cell sarcomatoid carcinoma. The prognosis is better than that of other breast sarcomas. The prognostic factors are not fully known because of the limited number of studies. The benefits of chemotherapy, radiotherapy and hormonal therapy are still controversial. However, there is a need for further studies to determine the prognostic factors. E-PS-02-013 Peptidil argenin deiminase typ 4 level in blood samples of women with different molecular-genetic subtypes of breast cancer A. Semenova 1 , O. Tereshin 1 , A. Vagenin 1 , I. Dolgushin 2 1 Chelyabinsk Oncology Clinic, Russia, 2 South-Ural Medical University, Russia Background & Objectives: Elevated peptidyl arginine deiminase type 4 (PAD-4) enzyme activity in breast cancer is a well-documented fact, but little is known in connection with molecular – genetic subtypes of breast carcinoma. Methods: PAD-4 level was determined in serum samples of 98 women with primary breast cancer in period January 2017 – april 2018. They were divided in 5 subgroups based on standart IHC data: group 1 – luminal A cancer, 2 - luminal B Her-2 negative, 3 - luminal B Her-2 positive, 4 - non-luminal Her-2 positive, 5 - triple negative cancer. Samples were obtained before initiation of any oncologic treatment and in 41 cases again 15-24 days after definitive surgery. Also 20 samples were taken from 20 healthy women. PAD-4 level was determined with Human PAD-4 ELISA Kit n automatic analyser ADALTIS Personal LAB. Statistical analysis performed by means of IBM SPSS Statistics 19. Results: Median PAD-4 level before treatment was 9,0 ng/ml, with the same 9,0 ng/ml median level after surgery. Median enzyme levels for cancer subgroups were as follows: group 1 - 11,05 ng/ml., group 2 - 11,9 ng/ml., group 3 -10,8 ng/ml., group 4 - 7,99 ng/ml., group 5 - 9,9 ng/ml. Median PAD-4 level for healthy women was 1,5 ng/ml (Q1=0,0; Q3=2,0) ng/ml, which is significantly different from cancer group ( Mann –Whitney U test, U=38,500, p<0,001). Conclusion: PAD-4 level was higher in luminal cancer, but further research is needed to make definitive conclusions. E-PS-02-014 Breast cancer subtypes - single institution results of 11754 consecutive cases P. Drev 2 , O. Blatnik 2 , J. Blazina 2 , J.A. Bandres Contreras 2 , G. Gasljevic 1 , M. Gjidera 2 , B. Grcar Kuzmanov 2 , A. Klevisar Ivancic 2 , S. Pavlovic 2 , B. Gazic 2 1 Department of Pathology, Institute of Oncology Ljubljana, Slovenia, 2 Institute of Oncology Ljubljana, Slovenia Background & Objectives: Invasive breast carcinoma (IBC) is a heterogenous disease consisting of a number of subtypes with different prognostic and predictive characteristics. Assessment of breast carcinoma subtypes (BCS) is a crucial factor for management of IBC. Published large-series, long-term, single-institution data on observed frequencies of BCS are scarce. Methods: Institutional database was searched for IBCs in the period 2006-2018. BCS were classified using molecular tumour biomarkers. ER and PR were assessed immunohistochemically. Cut-off was 1%. HER2 was assessed with both IHC and FISH. Cut-off set according to valid ASCO guidelines. IHC and FISH protocols were EQA monitored. Analysis was performed to obtain data (average and annual variation) on predictive factors (PF) ER, PR, HR, HER2 and BCS. Results: 11754 consecutive IBC were identified. PF results:87.3% ER, 75.6% PR, 87.7% HR and 13.3% HER2 positive. BCS results: 78.3% luminal-A, 9.3% luminal-B, 3.9% HER2-positive and 8.5% triple-negative (TN). Annual variation was minimal in all PF and BCS, however there is a slight increase in both luminal subtypes and a slight decrease in HER2-positive and TN. Conclusion: Observed proportions of luminal A (78.3%) and B (9,3%) subtypes are in line with latest reports but slightly higher compared to majority of reports, while proportions of HER2-positive (3,9%) and TN (8,5%) are slightly lower compared to reported values. Observed slight increase of frequencies of luminal subtypes and decrease in HER2-positive and TN are in line with recently published population studies that show increasing incidence of ER-positive and decreasing incidence of ER-negative IBC. E-PS-02-015 In situ lobular carcinoma involving the sclerosing adenosis: a report of two case G. Kir 1 , H. Gunel 1 , A. Aydin 1 1 Istanbul Medeniyet University, Department of Pathology, Turkey Background & Objectives: Sclerosing adenosis is a common lesion in the breast. Sclerosing adenosis may rarely contain lobuler carcinoma in situ (LCIS) foci and may cause diagnostic challenge. Methods: We report the first case of a 44-year-old premenopausal women and the second case of a 55-year-old postmenopausal women, both presented with breast pain. On ultrasonography of the fırst case demonstrated a 8 mm solid isoechoic mass which is a well contoured lesion including milimetric calcification. The second patient’s ultrasonography showed a 12 mm solid hypoechoic noduler lesion. Both mammographies were unremarkable (BIRADS 0). The patients underwent core-needle biopsy. Results: On the microscopic evaluation of both cases revealed stromal fibrosis and expanding solid tubules which preserved lobular architecture.LCIS morphology was seen in most of the tubules. The dyscohesive cells in this tubules were uniform with peripheral round nuclei. On immunohistochemical analysis, myoepithelial cells were observed with p63, CK14, E-kadherin and β- catenin stains. E kadherin and β-catenin staining were lost in the epithelial cells filling the tubulus. Diffuse ER and PR expression were observed. The diagnosis were consistant whit lobular carcinoma in situ involving the sclerosing adenosis. Conclusion: The presence of LCIS in sclerosing adenosis is rare and may be misdiagnosed as invasive mammary carcinoma. Immunohistochemical staining may be used to resolve this confusion. E-PS-02-016 No special type invasive breast carcinoma transformed to metaplastic carcinoma after neoadjuvant chemotherapy G. Kir 1 , Z.C. Olgun 1 , O. Alimoglu 2 1 Istanbul Medeniyet University, Department of Pathology, Turkey, 2 Istanbul Medeniyet University, Department of General Surgery, Turkey Background & Objectives: Metaplastic breast carcinoma is a rare and aggressive type of breast carcinoma. Here, we report a case of metaplastic breast carcinoma which transformed from Invasive Breast Carcinoma, No Special Type (NST) following neoadjuvant chemotherapy (NAC). Methods: 46 year-old woman presented with a palpable mass which was diagnosed with tru cut biopsy as invasive breast carcinoma, NST. The patient received 4 cycles of NAC with anthracyclin and taxane Results: The patient underwent a segmental mastectomy after NAC. Microscopically the tumour was arranged in a diffuse pattern. Tumour cells had large vesicular, irregular nuclei with prominent nucleoli and abundant cyoplasm. Necrosis was detected in large areas. The neoplastic cells of the excised tumour were estrogen receptor (ER), progesterone receptor (PR), and HER-2 negative whereas on previous biopsy tumour cells were diffusely positive for ER and PR and negative for HER-2. After NAC tumour showed diffuse positivity for EGFR and vimentin, scattered cells stained with P63 and HMWCK. EMA was patchy and weakly positive at neoplastic cells. Tumour was negative for PANCK, CAM 5.2, Cytokeratin 5/6, Cytokeratin 14, and CD34. So the tumour was consistent with metaplastic carcinoma. Conclusion: Immunhistochemical changes after NAC is not an uncommon finding but morphologic transformation is very rare entitiy. This is the third case of transformation to metaplastic carcinoma after NAC as far as we know from English literature. E-PS-02-017 The distribution of morphomolecular subtypes of breast cancer in patients who recieved neoadjuvant therapy and breast-conserving surgery M. Urezkova 1 , A. Kudaybergenova 1 , E. Turkevich 1 , V. Klimashevsky 1 , P. Krivorotko 1 1 N.N. Petrov National Medical Research Center of Oncology, Russia Background & Objectives: Beginning with the B-14 NSAB study, the concept of neoadjuvant (pre-operative) therapy for breast cancer is in common use with oncologists. According to P. Cortazar, the frequency of pre-operative therapy is up to 80% in different biological subtypes. The aim of our study is to determine the proportion of BCS after pre-operative therapy, distribution of biological subtypes in this patients and proportion cases achieved complete pathological response (pCR). Methods: The study included 1016 cases of breast cancer treated with neoadjuvant therapy and subsequent surgery in our center in 2013-2018. Results: BCS after neoadjuvant therapy was 206 cases (20,2% of patients treated with neoadjuvant therapy and 16% of BCS in total). The distribution of biological subtypes in the group of patients receiving neoadjuvant therapy and BCS: “All luminal subtypes”- 119 (57.7%); “HER2-positive”- 21 (10%); “Triple-negative (TNBC)” - 58 (28%); “All luminal subtypes”- 119 (57.7%); “HER2-positive”- 21 (10%); “Triple-negative (TNBC)” - 58 (28%); In the BCS group pCR was recorded in 23% of cases. Distribution in this group: “All luminal subtypes” – 13 (27%); “HER2-positive” – 10 (20,8%); “TNBC” – 25 (52,2%). “All luminal subtypes” – 13 (27%); “HER2-positive” – 10 (20,8%); “TNBC” – 25 (52,2%). Conclusion: The proportion of BCS after neoadjuvant therapy in our study is significantly less than that described in international studies nevertheless in TNBC we achieved maximal response to pre-operative therapy and can avoid surgery as option for this group. E-PS-02-018 Androgen receptor expression in non-metastatic breast cancer: has it go any prognostic and predictive value? D. Lokuhetty 1 , B.I. Ruiz 2 , H. Wijesinghe 3 , V. White 2 , I. Cree 1 1 International Agency for Research on Cancer, France, 2 IARC/WHO, France, 3 University of Colombo, Sri Lanka Background & Objectives: Androgen receptor (AR) is emerging as an useful prognostic and predictive marker in breast carcinoma (BCa). Evidence points towards different AR signalling pathways in molecular BCa subtypes with different oncogenic roles. Several studies document AR to have prognostic value in early, non-metastatic BCa, but subtype is less evaluated. The predictive role of AR for targeted therapy has not been evaluated extensively. This systematic review protocol plans to summarize the prognostic and predictive value of AR expression in non-metastatic breast cancer. Methods: Electronic databases (PubMed, EMBASE, Cochrane Library, WOS) will be searched. Data base specific search terms related to the review question, such as “breast neoplasm”, “androgen receptors”, but also other expressions “breast cancer”or “AR expression” will be combined into a tailored search strategy that will include all references from 1980 to March 2019 in English, Spanish, German or French. Studies will be included if they analyse the relation between the AR and its prognostic or predictive value in women with non-metastatic breast cancer, reporting on outcome measures, such as overall survival, disease free survival, progression free survival or median survival. Results: Results will be screened by two independent reviewers and the initial selection full-text assessed applying eligibility criteria. Data from included papers will be extracted into standardised forms including participant and prognostic factor information, outcomes and effect size. Risk of bias of studies will be assessed using the Quality Prognostic Studies tool and quantitative synthesis of results performed. A narrative synthesis of results will include description of strength and consistency of outcomes, as well as the methodological quality of the studies. Conclusion: This review will synthesize available evidence for the prognostic and predictive value of AR expression in non-metastatic BCa considering subtypes. Research gaps will be identified and recommendations drafted. The results will update to the 5th series of WHO Classification of Tumours. Review title will be registered and protocol will made available. E-PS-02-022 Suspicious microcalcifications associated to Xanthogranulomatous Mastitis L. Campos Clemente 1 , L. de Medeiros Reis 1 , M.L. Balancin 1 , M. Abrantes Giannotti 1 1 Department of Pathology, University of Sao Paulo, Brazil Background & Objectives: Xantogranulomatous Mastitis (XM) is benign, usually self-limited inflammatory condition of the breast. No clear etiology has been established, electing it as an exclusion diagnosis: special stains and cultures should be negative and differentials as histiocytic diseases should be excluded, as well as malignancy. In this series we have reported a cohort of XM cases and evidenced a distinct group of calcification-associated XM. The main objectives of this study were to build an exploratory case series on XM cases from a Brazilian Cohort of patients and describe associated findings. Methods: Data was extracted from pathology report of our institutional pathology files after an extensive systematic retrieval from the laboratory informatics system on patients subjected to breast biopsies (including core biopsies) and resection specimens from the last 10 years. Results: 37 women subjected to breast biopsy or resection were retrospectively reviewed from our institutional pathology files. 32 (89%) were biopsy specimens, while 5 (11%) were resection; 17 were located on the right breast (46%) and 20 on the left (54%). Superior quadrants (24, 65%) were followed by retroareolar (14%) and other breast regions. Clear steatonecrosis criteria was evidenced in 9 cases (24%), calcifications, including distrophic and microcalcifications, were evidenced in 11 cases (30%). Other findings reported were usual ductal hyperplasia (2), atypical ductal hyperplasia (1), collunar cell changes (3) and pseudoangiomatous stromal hyperplasia and fibroadenomatoid changes (2). In a subgroup analysis, microcalcification was statistically distinct from other grouped features (p= 0.004, IC (-0.799 - -0.221)). Special stains were performed and resulted negative. Conclusion: XM is an exclusion diagnosis, usually directly made after special stains result negative. In this series, the presence of a microcalcification group associated to XM in biopsies performed to exclude malignant microcalcifications reveals that this diagnosis should be considered more often as a differential in the breast microcalcifications workup. We have presented a summary of findings for XM and reviewed the most common associated findings, especially the association to microcalcifications, suggesting the important of relying in this differential diagnosis during a microcalcifications workup. E-PS-02-023 New about the "natural history of cancer" V. Danilenko 1 , V. Onufrieva 1 , A. Filin 1 1 Voronezh State Medical University named after N.N. Burdenko, Department of Pathological Anatomy, Voronezh, Russia Background & Objectives: The aim of the study was to clarify ideas about the «natural history of cancer», particularly breast cancer. Methods: 765 cases of surgical material of breast cancer were studied (protocols of gross-descriptions and microslides). The dynamics of changes in the tumour volume were determined. Results: The average volume of breast cancer nodes in five decades of women's lives did not differ significantly. Similar was the frequency of occurrence of nodes with cancer-stages double the volume (8sm 3 ). By fluctuating in the zone of small volumes, the cancer nodes reached stable maximum in the region of linear dimensions of about 2.5 cm (>8 cm 3 ). Conclusion: The obtained data shows that the nodes of breast cancer grow unevenly, sharply slowing the growth rate as its volume increases. Hence, the single data on the doubling of the volume of specific nodes of breast cancer for some time intervals cannot be extrapolated to the entire «natural history of cancer», as it was postulated before. E-PS-02-024 Profile of Adenoid Cystic Carcinoma (ACC) of the breast: A 17 year-histopathological review of 13 cases L.L. Sousa Veras 1 , M. Alvares Leão 1 , A. Uema Watanabi 1 , N. Soares de Menezes 2,1 1 Barretos Cancer Hospital, Brazil, 2 European Society of Pathology, Brazil Background & Objectives: Adenoid cystic carcinoma (ACC) of the breast is a rare subtype. It occurs in less than 0.1% of patients with breast cancer. The objective of this study was to determine the clinical, histological and immunohistochemical features of these tumours. Methods: A retrospective review between January 2002 and March 2019 was performed using the cancer registry database in a single reference center for cancer treatment in Brazil. Results: Thirteen patients were diagnosed with ACC. The mean age of the patients was 63.8 years (52-87 years). There was only one male patient. Only 3 patients reported a familial history of breast cancer. There was one case of intraductal carcinoma in the contralateral breast. The size of tumour ranged from 2.0 to 7.5cm. 46% of the patients underwent mastectomy with sentinel lymph node biopsy. The nodal status was positive in just one case. All cases were HER-2 negative. There was only one case in which estrogen and progesterone receptors were positive. Follow-up was done in 53% of patients with 85% patients being free of disease in the last follow-up. There was only one case of distant metastasis for the lung. Conclusion: Adenoid cystic carcinoma is a rare special subtype of breast cancer with good prognosis despite being a triple-negative tumour. Program of Assistance and Incentive to the Researcher (PAIP) - Pio XII Foundation, Barretos, SP E-PS-02-025 HER positivity in breast cancer is not associated with Ki67 of <5% and 50% of HER2 positive breast cancer are PR negative S. Javidparisijani 1 , I. Kim 1 , S. Pambuccian 2 , P. Tang 1 1 Loyola University Medical Center, USA, 2 Loyola Univeristy Medical Center, USA Background & Objectives: HER2 over-expression or amplification is a poor prognostic factor for breast cancer, It has been suggested to associate with younger patients, higher grades and higher Ki67 expression. ASCO/CAP guidelines recommend all primary breast cancer being tested for HER2 by either IHC or FISH as the primary test, and reflexed to the other test if IHC is equivocal (2+) or FISH is inconclusive. It has been our institutional policy that all HER2 IHC 1+ to 3+ cases reflexed to FISH analysis. Taking the advantage of our available data set, we investigated the relationship between HER2 positivity and these clinico-pathological features, and with a focus on Ki67 and PR expression levels. Methods: We have reviewed our archival data for primary breast cancer between Jan 2015 and June 2018, and identified 278 cases with both HER2 IHC and FISH analysis. The clinico-pathologic features including patient age, histologic type, histologic grade, and expression of ER, PR and Ki-67 were documented, and the evaluation of positive HER2 with tumour grade, patient age, and ER, PR and Ki67 expression were conducted. Results: Among the 278 cases studied, 71 cases are HER2 positive, included 3%, 31% and 66% as grade 1, 2, and 3 tumours, respectively; and 4%, 41% and 55% of tumours are in 60 years of age groups, respectively. 1) As in relation to Ki-67 expression levels (20%), no tumour with <5% Ki67 expression has positive HER2 regardless of its histologic grade. 2) HER2 positivity is noted in between 5-11% in ER negative and 44-57% in PR negative Grade 2 and grade 3 tumours. 3) There is no significant age difference among different age groups noted between HER2 positive and HER2 negative tumours, even within the same histologic grade. Conclusion: Ki-67 expression of <5% is not associated with HER2 positive; and over 50% of HER2 positive tumours are PR negative. Larger studies are warranted to confirm these finding; so it could provide guidance to pathologists in perform HER2 reflex test. E-PS-02-026 Sequential multiplex immunohistochemistry and virtual image reconstruction using a single slide for quantitative Ki67 proliferation index measurement in breast cancer: method development and validation G. Serna 1 , S. Simonetti 1 , R. Fasani 1 , F. Pagliuca 2 , P. Gallego 1 , L. Alonso 1 , X. Guardia 1 , J. Jimenez 1 , P. Nuciforo 1 1 Molecular Oncology Group, Vall d'Hebron Institute of Oncology (VHIO), Spain, 2 Department of Advanced Biomediacal Sciences, Pathology Unit, University of Naples "Federico II", Italy Background & Objectives: Immunohistochemical (IHC) stain of Ki67 is a prognostic and predictive marker in breast cancer (BC). However, manual scoring (MS) is semiquantitative at best and suffers from high inter-observer variability which limits its clinical value. Methods: We developed an innovative digital image analysis (DIA) workflow which uses sequential Ki67 and cytokeratin (for precise automatic tumour cells recognition) IHC staining on the same section. Ki67 proliferation index was determined by DIA and MS in 4 tissue microarrays containing 257 breast cancer tissue cores divided in training (n=140, HR+) and test (n=117, HER2+ and TNBC) sets. Agreement between DIA and MS was calculated using intraclass correlation coefficient (ICC) and Bland-Altman (BA) plot. Results: In the training set, 124 and 121 cores were evaluable for DIA and MS, respectively. ICCs were 0.928 and 0.807, depending if a cytokeratin mask was used or not. When applied to the test set (115 evaluable cores for DIA and 100 for MS), ICCs were 0.821 with mask and 0.727 without the mask. BA plot revealed that the distance between DIA and MS increased with the magnitude of Ki67 measurement and positively correlated with analysed tumour area. Conclusion: Sequential multiplex IHC combined with DIA represent a valid alternative to MS for Ki67 measurement. The observed increase in difference between the two methodologies with increasing Ki67 values does not directly impact on clinically relevant thresholds, but points to the poor quantitative nature of MS. Additional data on DIA reproducibility and agreements across different cut-offs will be presented. E-PS-02-027 Lymphoepithelioma-like carcinoma of the breast: a case report C. Gkogkou 1 , E. Baliou 1 , E. Koniaris 1 , E. Gioti 1 , E. Moula 1 , G. Kafiri 1 1 "Hippokratio" General Hospital of Athens, Greece Background & Objectives: Lymphoepithelioma-like carcinoma (LELC) is an exceptionally rare tumour of the breast with only a few cases reported in the literature. It mimics its nasopharyngeal counterpart and its possible correlation to HPV is still being investigated. Here we present a case of LELC of the breast because of its rarity and the diagnostic challenges it poses on histological level. Methods: A 57 year-old woman presented with a tumour located in the left breast. Lumpectomy was performed and the surgical specimen was submitted for histological examination. Sectioning of the excised specimen revealed a white, solid, firm tumour measuring 1.6cm and irregular, stellate border. Results: Microscopically the tumour was composed of large cells with eosinophilic cytoplasm and pale stained nuclei with prominent nucleoli. The cells were arranged in solid nests and small trabeculae, separated by a dense inflammatory infiltrate, composed of small lymphocytes. Lymphoid follicles were also evident. The periphery of the tumour was frankly invasive and no syncytial growth pattern was observed. There was no evidence of necrosis. Mitotic activity was increased. Neoplastic cells were immunoreactive for CK8/18 and e-Cadherin. They didn’t stain for ER, PR and Her2. Ki-67 proliferation marker was positive in approximately 30% of the malignant cells. Based on the above findings, the diagnosis of LELC was established. Conclusion: The main differential diagnosis of LELC of the breast is medullary carcinoma. The lack of circumscription and the absence of syncytial growth pattern will aid to the correct diagnosis. Pathologist awareness is required to avoid possible diagnostic pitfalls. E-PS-02-028 Uncommon metastasis of invasive lobular breast cancer to the endometrium,an endometrial polyp, the cervix and a leimyoma: a case report and review of the literature G. Benkhedda 1 , I. El Hafaia 2 1 University Algiers, Algeria, 2 EHS Centre Pierre et Marie Curie, Algeria Background & Objectives: Although it is known that breast cancer can metastasize to many organ sites, metastasis to the uterus is uncommon and usually occurs during widespread metastatic disease. Lobular carcinoma is not the most common histological subtypes of breast carcinoma, but it is the most frequent histologic type that causes gastrointestinal, ggynaecological and peritoneal metastases.When an extragenital tumour metastasizes to the uterus, it is predominantly located in the myometrium; in a minority of cases, the metastasis is confined to the endometrium. The main symptoms of the uterine metastasis depend on the anatomic involvement site. Abnormal uterine bleeding is by far the most important symptom. Uterine metastases account for approximately 4% of genital tract metastases, with 47% of cases involving the breast as the primary site. Methods: A 50-year-old woman was complaining of postmenopausal uterine bleeding and leucorrhea. Her medical history revealed that she was diagnosed with breast carcinoma 4 years ago. At that time she enderwent a radical mastectomy associated with axillary lymph node dissection pathological examination of the tumour revealed Grade 3 infiltrating lobular carcinoma; stage IIIa (T2 N2 M0).A diagnostic work‑up was initiated to detect possible causes of vaginal bleeding. She underwent transvaginal ultrasound, which revealed endometrial thickening (13 mm). A hysteroscopic examination revealed an endometrial polyp in the uterine cavity, which was resected. The morphology and immunohistochemical studies confirmed the diagnosis of metastasis of lobular breast carcinoma to an endometrial polyp. The patient then underwent a total abdominal hysterectomy with bilateral salpingo‑oophorectomy and partial colectomy. Results: The hysterectomy measuring (8x5x4). The section slice showed an intramural leiomyoma measuring 3 cm. The cervix presents a white thickening in some places. Pathology results demonstrated that the endometrium,the uterine leiomyoma and the cervix shared the same histopathological features as those presented by the primary lobular breast carcinoma. Conclusion: Uterine metastases of breast cancer are very rare; the presence of abnormal bleeding symptoms in a patient with a history of breast cancer should be suggestive of endometrium metastatic disease especially in case of invasive lobular carcinoma. The current review presents the second reported case of lobular breast carcinoma metastasizing to an endometrial polyp, the cervix and a leiomyoma simultaneously. E-PS-02-029 Immunohistochemical analysis of cancer stem cell markers CD 133 and ALDH1 expression in carcinoma breast J. Kini 1 , K. Jeepalem 1 , H. Kini 1 , K. Sahu 1 1 Department Of Pathology, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, Karnataka, India Background & Objectives: Carcinoma breast is the most commonly diagnosed malignancy, accounting for 22% of all malignancies in women. In India, breast cancer ranks second to cervical cancer with increasing incidence in both developed and developing countries. Carcinoma breast encompasses numerous histological sub-types with unique molecular features and therapeutic response. The aim of the study was to analyse and correlate the expression of cancer stem cell markers CD133 and ALDH1 in carcinoma breast with that of size, stage, grade of tumour, lympho-vascular invasion and lymph node status. Methods: Immunohistochemistry was performed with CD133 and ALDH1 on 130 retrospectively and prospectively collected cases of carcinoma breast. The study samples included mastectomy specimens of breast cancer. Clinical details were retrieved from the case files. Histopathology findings and ER, PR, Her-2 neu status were noted. Results: A total of 53 cases (40.8%) stained positive for CD133 marker. Similarly, 30 cases stained positive for ALDH1. In the study, more than half of the cases were negative for both CD133 and ALDH1 cancer stem cell markers (55.4%, n=72), whereas about 20% of the cases stained positive for both CD133 and ALDH1 expression. The expression of CD133 had a highly significant correlation with the grade of tumour (p=0.0005). Increased expression was seen in grade 3 tumours. Expression of ALDH1 had a significant correlation with the size of tumour (p=0.0005). Combined expression of CD133 and ALDH1 had a statistically significant correlation with the grade of tumour (p=.0005) and size of tumour(p=0.008). Conclusion: In our study, we analysed the expression of CD133 and ALDH1 CSC markers in carcinoma breast. CD133 was significantly associated with increased tumour grade. There was significant correlation between ALDH1 expression and tumour size. In combination both the markers correlated significantly with grade and size of the tumours. Identification of cancer stem cells and early intervention with targeted therapy might be of clinical use for a better patient prognosis. E-PS-02-030 Immunohistochemical evaluation of the possible prognostic significance of MTA-1 protein in breast cancer M. Lambropoulou 1 , A. Maroudas 1 , V. Papadatou 1 , S. Tologkos 1 , O. Pagonopoulou 2 , I. Balgkouranidou 1 , N. Xenidis 3 , G. Tripsianis 4 , L. Yorkas 1 , S. Meditskou 5 , N. Papadopoulos 1 1 Histology-Embryology Lab., Medical Department, Democritus University of Thrace, Greece, 2 Physiology Lab., Medical Department, Democritus University of Thrace, Greece, 3 Dep. of Clinical Oncology, Medical Department, Democritus University of Thrace, Greece, 4 Medical Statistics Lab., Medical Department, Democritus University of Thrace, Greece, 5 Histology-Embryology Lab., Medical Department, Aristotle University of Thessaloniki, Greece Background & Objectives: Breast cancer is the most common type of cancer in women and the major type responsible for their mortality. For that reason, new cancer prognostic biomarkers are being developed, such as the gene of MTA-1 protein. This particular protein belongs to the metastasis associated proteins family (MTA) and is encoded by the corresponding gene located on chromosome 14q32.33. High expression levels of MTA-1 are observed in cases of tumours and its levels are directly related to cancer aggression and the possibility of metastasis. Expression of MTA-1 has been observed in various types of cancer, such as liver, gastric and ovarian cancer. This research work aims at the immunohistochemical study of the expression of MTA-1 protein in breast cancer and its correlation with clinical-histopathological parameters. Methods: We used 26 breast tissue specimens derived from patients with various cancer subtypes. Of these 26 patients 24 were women and 2 were men. Indirect immunohistochemistry was performed, using anti-MTA-1 antibody and the expression levels of MTA-1 were then tested and correlated with clinical-histopathological parameters. Results: Positive expression of MTA-1 was observed in 20 of 26 patient samples. Furthermore, the presence of lymph node metastases was correlated with high MTA-1 levels with statistical significance (p <0.001). Conclusion: Based on the results of this study, we concluded that MTA-1 protein is a potential effective prognostic marker for this disease and can possibly be used as a therapeutic target. However, due to small sample pool further investigation is required. E-PS-02-031 Role of protein P66 SHCA in programs epithelial-mesenchimal transition in invasive carcinoma of no special type T. Bezuglova 1 , A. Erzieva 1 , T. Bezuglova 1 , L. Kaktursky 1 , M. Mnikhovich 1 , A. Asaturova 2 , V. Kometiva 3 , I. Vasin 4 , S. Snegur 4 , K. Bunkov 4 , D. Kushch 5 , N. Malyugin 5 1 Research Institute for Human Morphology, Russia, 2 FSBI 'National Center for Obstetrics, Gynaecology and Perinatology named after V.I.Kulakov' Ministry of Healthcare Russian Federation, Russia, 3 National Medical Research Center of Obsterics, Gynaecology and Perinatalogy, Russia, 4 Ryazan Reginal Clinical Hospital, Russia, 5 Pirogov Russian National Research Medical University (Moscow), Russia Background & Objectives: Protein P66 SHCA can act as a suppressor and stimulator of carcinogenesis in different types of tumours.p66Shc is involved in the regulation of individual types of cell death and it also participates in the pathogenesis of malignant tumours..p66Shc is involved in the regulation of individual types of cell death and it also participates in the pathogenesis of malignant tumours. Methods: Researched material of 35 patients with ICNst after radical mastectomy.30 patients (n =30) with metastases in regional lymph nodes, liver, lungs and brain, 5 patients (n = 5) without metastatic lesion. Age of patients was 35-85 years .Patients before the operation did not receive neoadjuvant therapy. The diameter of the tumour site is 0.8-4.0 cm. The degree of malignancy ICNST is G 2- G 3. The research was carried out by using light microscopy and IHC method with the protein p66ShcA ( Abcam ) and E-cadherin (Dako , LabVisionFlex)with a semi-quantitative estimate. Results: Expression ofp66ShcAproteinis higher in invasive carcinoma of no special type (ICNST)with confirmed metastases (n= 30) in lymph nodes, liver and brain, than in breast cancer without metastases (n= 5). The severity of the cytoplasmic membrane expression was (+++) in the anaplastic component of tumours (epithelial-mesenchymaltransition zone), unlike fields with a more differentiated tumour component in parallel with changes in expression of E-cadherin (reduced expression of change, until complete disappearance). Conclusion: The high expression level of p66shccorrelateswith an unfavourable prognosis for breast cancer, which was shown by us in the areas of invasive growth (epithelial-mesenchymaltransition zone) innon-specificcarcinoma.Proteinp66ShcA is one of the first diagnostic biomarkers for identifying malignant tumours with an unfavourable prognosis and aggressive course, regardless of the molecular subtype. E-PS-02-032 Fibromatosis-like spindle cell lesion occurring after breast reconstruction with omental flap: a case report S.G. Song 1 , J.H. Moon 1 , M. Jung 1 , Y.J. Hwang 1 , J.H. Kim 2 , H.S. Ryu 2 , I.A. Park 2 1 Department of Pathol, Seoul National Univ. Hosp., Republic of Korea, 2 Department of Pathology, Seoul National University College of Medicine, Republic of Korea Background & Objectives: Recently, omental flap has been widely used as one of the autologous breast reconstruction methods after surgery. Some complications related to omental flap were reported, including short-term regional problems and recurrence of breast cancer. Methods: Here, we report a case of fibromatosis-like proliferative lesion in a patient with intraductal breast carcinoma who had a nipple-sparing mastectomy and reconstruction with omental flap. Results: The patient was a 54-year-old woman who was diagnosed with metachronous intraductal carcinomas in the bilateral breasts. She received breast-conserving surgery for the left breast and eight months later, she undergone nipple-sparing mastectomy and immediate reconstruction using omental-flap for the right breast . Three years later, she complained of palpable mass in reconstructed right breast. Needle biopsy of the mass revealed atypical spindle cells lesion showing focal positivity to cytokeratin in immunohistochemistry stain. She received total mastectomy under a suggestion of metaplastic carcinoma. However, the histologic analysis of the mastectomy specimen showed infiltrative bland-looking spindle cell proliferation resembling fibromatosis or nodular fasciitis and expressed β-catenin in the nuclei. Cytokeratin expression was observed only in a few cells. She was finally diagnosed as fibromatosis-like proliferative lesion. Conclusion: To the best of our knowledge, this is the first case report of tumour occurrence other than recurrence of carcinoma in omental flap. The diagnosis of the newly occurred lesion with positive staining of cytokeratin in reactive fibroblasts in the harvested omentum was difficult because the possibility of breast cancer recurrence, especially fibromatosis-like metaplastic carcinoma should be ruled out. E-PS-02-033 Elastic fibers in microenvironment of invasive ductal carcinomas of breast S. Rjabceva 1 , I. Siamionik 1 , M. Derevyanko 1 1 Institute of Physiology of National Academy of Sciences of Belarus, Belarus Background & Objectives: Collagen components in the tumour microenvironment substantially influence cancer pathogenesis and progression. Nevertheless, status of elastic fibers and its prognostic role remain unclear. The aim of this study is to estimate the changes of stromal elastic fibers in breast invasive ductal carcinoma. Methods: Forty-seven slides from 42 female patients were investigated in this prospective study (median 1 slide/case). Histochemical studies for Russell-Movat pentachrome stain was done. Results: The mean age of the patients was 66.5 (range 30-86). The mean of tumour size was 2.1 cm (range = 0.9-3.0 cm). 25 (59.5%) of the patients had low grade cancer, 14 (33.3%) – medium grade and 3 (7.1%) of the patients had high grade. Lymph node metastases was detected in 21 (50.0%) cases. Thickened elastic fibers was found in tumour tissue in 37/88.1% of patients: around vessels (37/88.1%), in stroma (24/57.1%) and around ducts (15/35.7%). Gamma`s correlation analysis revealed the associations between an increasing of thickness of elastic fibers around vessels and tumour grade (r=-0.35, p <0.05). Conclusion: This study showed that the change in the thickness of the elastic fibers in breast invasive ductal carcinoma microenvironment is related to tumour grade. Low grade breast carcinoma of no special type characterised by formed of thickened elastic fibers around vessels often than high grade carcinoma. E-PS-02-034 Expression of oestrogen receptor, progesterone receptor, and HER2 between primary breast carcinomas and metastatic carcinomas to the lung H. Lee 1 , W. Han 2 , S. Im 3 , J.H. Kim 4 , H.S. Ryu 4 , I.A. Park 4 1 Department of Pathology, Chungbuk National University College of Medicine, Republic of Korea, 2 Department of Surgery, Seoul National University College of Medicine, Republic of Korea, 3 Department of Internal Medicine, Seoul National University College of Medicine, Republic of Korea, 4 Department of Pathology, Seoul National University College of Medicine, Republic of Korea Background & Objectives: Estrogen receptor (ER), progesterone receptor (PR), and HER2 are major immunohistochemical (IHC) markers of breast carcinoma. We analysed the difference of IHC markers among primary breast carcinoma specimen without prior chemotherapy (PBC1), post-neoadjuvant chemotherapy specimen of primary breast carcinoma (PBC2), and metastatic carcinoma to the lung (MCL). Methods: One hundred cases were selected in which paraffin blocks of MCL and PBC1 and/or PBC2 were available. All PBC1, PBC2, and MCL specimens were available in 31 cases. Expression of ER, PR, and HER2 was studied in the PBC1, PBC2, and MCL. McNemar test was used for the changes of the markers among the groups. Results: There was a tendency of loss of PR expression between PBC1 and MCL (p=0.095). This tendency was also shown between PBC1 and PBC2 (p=0.074). However, there was no difference between PBC2 and MCL. Changes of ER and HER2 were not significant among the groups. Subtype was changed in seven of 87 cases (8.04%) between PBC1 and MCL, three of which were changed from luminal into triple negative and two of which were from HER2 and triple negative subtype. Three cases showed differences in subtype among PBC1, PBC2, and MCL: Subtype of PBC2 in these cases was all triple negative subtype. Subtype of MCL was the same as PBC1 in one case and as PBC2 in two cases, respectively. Conclusion: IHC studies for ER, PR, and HER2 should be assessed in the resection specimen or metastatic lesion after neoadjuvant or adjuvant chemotherapy for establishing the further treatment plans. E-PS-02-035 Invasive cribriform carcinomas of the breast: histopathological and prognostic features S. Demir 1 , A. Akder Sari 1 , B. Bolat Kucukzeybek 1 , S. Yigit 1 , D. Etit 1 , A. Yazici 1 , Y. Kucukzeybek 2 1 Izmir Katip Celebi University Ataturk Training and Research Hospital, Department of Pathology, Turkey, 2 Izmir Katip Celebi University Ataturk Training and Research Hospital, Department of Oncology, Turkey Background & Objectives: Invasive cribriform carcinoma (ICC) is a rare type of invasive breast cancer which has three histological forms: the pure invasive type (>90% of cribriform pattern); the invasive type , predominant invasive cribriform pattern accompanied by a component of tubular carcinoma; the mixed type (except tubular carcinoma). Our aim is to evaluate histopathological and prognostic features of ICC of the breast. Methods: ICC of the breast diagnosed between 2008-2019 in our department was included in our study. Results: The study population consisted of 40 female patients (n=16 pure-ICC and n=24 mixed-ICC). Invasive ductal carcinoma was the predominant accompanying component (n=18/24, 75%). No invasive type was identified. The median age was 46,5 years (min43-max53) for pure ICC, and 59 years (min53-max65) for mixed-ICC. The median size of the tumour was 2 cm in both types. Low grade tumours were more frequent in pure-ICC (35.7% vs %21) whereas high grade tumours were more common in mixed-ICC (17.4% vs 7%). Lymph node metastases were present in 42.9% of pure-ICC and 50% of mixed-ICC. All of the tumours were ER and PR positive. Of all tumours, only one case of mixed-ICC was positive for CERB-B2. Ki67-index was <14% in all tumours except for 6 cases of mixed-ICC and 1 case of pure-ICC. The follow-up time for pure-ICC was 2 to 127 months (with a median of 81 months), and no recurrences/progression was identified. Conclusion: Pure-ICC of the breast is a very rare type of breast carcinoma, seen in younger patient population and has a very good prognosis. E-PS-02-036 Metastasis of extramammary malignancies to the breast - report of two cases S. Foreid 1 , J. Lopes 2,1 , J.M. Dias 1 1 Synlab Pathology Porto, Portugal, 2 Centro Hospitalar São João, Portugal Background & Objectives: Metastases of extramammary malignancies to the breast are a rare event, representing about 0,2%-1,3% of all mammary malignancies. Excluding hematological malignancies, the number drops well below 1%. The most common reported sites of origin include lung, skin, stomach and ovary. Due to the high frequency of primary breast cancer and the rarity of metastasis of non-mammary cancers to the breast, a new palpable mass in the breast is usually presumed to be a primary breast tumour. Recognition of a non-mammary breast metastasis is very important, as treatment and prognosis is very different. Here we report two cases of metastasis to the breast with primary origin in the colon and lung. Methods: Patients presented with a firm palpable mass in the breast, suspicious for neoplasia on image studies. Biopsy reveled an invasive carcinoma, G3 solid pattern with necrosis in one case, and an invasive carcinoma, G2 with papillary features on the other, both triple negative. No previous malignancy was known. Results: Specimens revealed well circumscribed tumours, with an unusual morphology, and absence of in situ carcinoma and calcifications, what made the pathologist suspect of metastasis. Immunohistochemistry helped make the correct diagnosis: metastasis of colon adenocarcinoma and metastasis of papillary lung carcinoma. Conclusion: Metastasis on extramammary carcinoma are rare in the breast. Some histological features help make the right diagnosis: unusual morphology, well-circumscribed lesion and absence of in situ carcinoma and calcifications. Immunohistochemistry is particularly helpful, if no previous history of malignancy is known. Making the right diagnosis is important as to avoid unnecessary procedures and treatment of these patients. E-PS-02-037 Immunohistochemical evaluation of stromal component of invasive carcinoma of no special type (IC NST) T. Bezuglova 1 , V. Kometova 2 , M. Mnikhovich 1 , L. Kaktursky 1 , A. Asaturova 3 , A. Erzieva 1 , I. Vasin 4 , S. Snegur 4 , K. Bunkov 4 , D. Kusch 5 , N. Malyugin 5 , A. Romanov 5 1 Research Institute of Human Morphology (Moscow), Russia, 2 Institution National Medical Research Center of Obstetrics, Gynaecology and Perinatology Ministry of Healthcare of the Russian Federation (Moscow), Russia, 3 FSBI 'National Center for Obstetrics, Gynaecology and Perinatology named after V.I.Kulakov' Ministry of Healthcare Russian Federation, Russia, 4 Ryazan Reginal Clinical Hospital, Russia, 5 Pirogov Russian National Research Medical University (Moscow), Russia Background & Objectives: We aimed to evaluate stromal component of invasive carcinoma of no special type (IC NST) using qualitative and quantitive immunohistochemical study. Methods: We have assessed the post-operative specimens of 118 patients (aged 40-80 years with mean age of 61 year old) with IC NST. Expression of smooth muscle actin, desmin, collagen IV and VEGF was studied. Results: In invasive carcinomas of solid type basement membrane was absent or disrupted, in scirrhus fragments of basement membrane were absent. Vimentin expression in stroma manifested as presence of fine cytoplasmatic granules, as well as staining of cells’ membranes. Most prominent smooth muscle actin expression was detected in invasive scirrhus. Expression VEGF was present in all forms of breast cancer, although in scirrhus it was minimal and was present in 16,3% of all cases. For breast cancer there is a pronounced topographical and quantitive relations between expression of these markers and growth patterns, tumour grade and stages of progression; myofibroblast-like markers (actin, vimentin) are not infrequently situated in the parenchyma and stroma. Collagen IV expression are lowered. Desmoplastic changes in scirrhus manifest with minimal expression of VEGF, other markers are expressed predominantly by stroma regardless to tumour stage. Conclusion: Our results signify importance of further studies of tumour stroma. E-PS-02-039 Cystic neutrophilic granulomatous mastitis - the importance of histological diagnosis C. Dahlstedt-Ferreira 1 , R. Rosas 1 , D. Gonçalves 1 1 Hospital Garcia de Orta, EPE, Portugal Background & Objectives: Cystic Neutrophilic Granulomatous Mastitis (CNGM) is a rare breast pathology that is believed to arise from Corynebacterium spp infection. We present a case of CNGM, a rare disease that clinically is a cancer mimicker. Methods: A 48 year old woman, multiparous, presented with a mass on her right breast on January 2018 and was thus submitted to antibiotics, without resolution. A year later, she underwent a mammogram, breast ultrasound and magnetic resonance, revealing a mass on her right breast, highly suspicious for a malignant lesion. Results: The core needle biopsy revealed a stromal mixed inflammatory infiltrate and numerous granulomas formed by epithelioid histiocytes, with cystic spaces on the inside, lined by a rim of neutrophils, with occasional multinucleated gigantic cells. In some cystic spaces we were able to identify gram positive bacilli. Conclusion: This mastitis is treated through surgical resection or lipophilic antibiotics, and can take weeks or months to be fully resolved. Through this case report, we want to show the distinctive histologic pattern of this rare entity, which is frequently highly suspicious for malignancy by radiology. E-PS-02-040 Breast metastasis: clinicopathological study of 11 cases M. Mellouli 1 , M. Triki 1 , R. Kallel 1 , I. Saguem 1 , W. Ghribi 1 , T. Sallemi Boudawara 1 , S. Charfi 1 1 Department of Pathology, Habib Bourguiba Hospital, Sfax, Tunisia Background & Objectives: Breast metastases are rare. They represent 0.4 to 6% of all breast cancers. Our aim is to discuss their clinicopathological features. Methods: We report a retrospective survey of 12 cases of breast metastases diagnosed over a period of 23 years (1992—2016) in the department of pathology of the university hospital of Sfax (Tunisia). Results: The diagnosis was carried on a material of cytoponction in two cases, a needle biopsy in seven cases and a surgery specimen in three cases. The primary tumours understood two cases of small cell non-Hodgkin lymphoma, a case of nasopharyngeal carcinoma, a case of retroauricular melanoma, a case of leiomyosarcoma, a case of uterine choriocarcinoma, a case of rectal neuroendocrine carcinoma, a case of small cell lung carcinoma, three cases of gastric adenocarcinoma and one case of a hematological malignancy of underminated origin. All patients were women with a middle age of 37 years. In only one case the mammary metastasis revealed the primary tumour. Clinically, the size average of tumours was 2.9 cm. Bilateral mammary involvement was noted in three cases. Conclusion: A confrontation of clinical and pathological data with immunohistochemical study is recommended for an accurate diagnosis of breast metastasis. E-PS-02-041 Unexpected metastatic axillary node in a high grade DCIS S. Khalid 1 , M.W.A. Mangat 1 , A. Arnaout 1 1 St George's University Hospital NHS Foundation Trust, United Kingdom Background & Objectives: Axillary node metastasis in pure DCIS is rare and has been reported in literature varying from 2-13% 1 . Methods: A 68 year old female, known to have an intermediate grade DCIS on the right breast treated by complete wide local excision two years ago, was found to have calcifications on the left breast. The biopsy showed high grade DCIS. She underwent left mastectomy and Sentinel Lymph Node Biopsy (SLNB). The frozen section of the SLN showed a 16mm macrometastatic tumour deposit. Results: Despite extensive sampling, sections from the left breast revealed an intermediate to high grade DCIS (ER and HER2 positive) and a 4.5mm focus of Grade 1 invasive ductal carcinoma, ER positive but HER2 negative. The macrometastatic tumour deposits in the sentinel node however had a completely different morphology and resembled the DCIS as both expressed HER2 receptor gene. All the other axillary nodes were negative. Radiological assessment of the right breast showed no abnormality. Conclusion: The morphology of the macrometastatic sentinel node was different from the Grade 1 IDC in the mastectomy, in fact it closely resembled the high grade DCIS and that’s why we labelled the IDC as an incidental finding. There is evidence of underestimation of invasive carcinoma on initial diagnosis in patients undergoing axillary node dissection for DCIS 2 . But there is no documentation about the possibility of high grade DCIS metastasising in the presence of small low grade focus of invasive cancer. This case is unusual and raises a challenge in the management of these patients. E-PS-02-042 Solid papillary carcinoma of the breast: an unusual carcinoma involving the breast R. Ayadi 1 , N. Boujelbene 2 , M. Driss 2 , L. Charfi 2 , I. Abbes 2 , H. Azaiez 3 , K. Mrad 2 , R. Doghri 2 1 Pathology Department, Military Hospital, Tunis, University of Tunis El Manar, Faculty of Medicine of Tunis, Tunisia, 2 Department of Pathology, Salah Azaiez Institute, Tunisia, 3 Department of Pathology, Salah Azaïez Institute, Tunis, Tunisia Background & Objectives: Solid papillary carcinoma of the breast (SPCB), a newly defined entity, is defined as a "distinctive form of papillary carcinoma characterised by closely apposed expansive, cellular nodules." This uncommon tumour frequently demonstrates neuroendocrine differentiation. To date, a few cases have been reported in the literature. We aimed to report a new case of SPCB and to describe its histopathological and immunohistochemical features. Methods: We report, a case of a 58-year-old female presented with a mass in the left breast. Results: A chirurgical biopsy was done and showed a well-circumscribed proliferation typically composed of solid papillary nodules.The diagnosis of SPCB was suggested. Based on these findings,a radical mastectomy with axillary lymph node excision were performed.The gross specimen identified a circumscribed tumour measuring 15 mm with predominantly solid components. Microscopy showed solid encapsulated tumour, with well-defined pushing borders, arranged in lobules with compactly arranged papillary fronds and branching networks of the fibrovascular cores.The tumour cells were bland-looking with low-grade atypia and few mitoses (< 5/10 HPF). On immunohistochemistry, tumour cells are positive for synaptophysin and negative for chromogranin and CD56. P63, a myoepithelial cell marker, is negative along the epithelial-stromal interface of the tumour.The final diagnosis of SPCB was established. Conclusion: SPCB is an unusual entity with distinctive clinicopathological features and an excellent prognosis.It should be distinguished from conventional breast carcinoma to avoid over-treatment. E-PS-02-043 Clinicopathological and genetic risk factors of regional metastasis in breast cancer patients V. Kometova 1 , O. Bourmenskaya 1 , M. Rodionova 1 , M. Dardyk 1 , Y. Dergunova 2 , P. Borovikov 1 , I. Balashov 1 , V. Rodionov 1 1 National Medical Research Center of Obstetrics, Gynaecology and Perinatology named after acamician V.I.Kulakov, Russia, 2 Ulyanovs Regional Clinical Oncological Center, Russia Background & Objectives: In 60–70% of breast cancer patients invasive axilla surgery appears to be unnecessary as pathology examination reveals no regional metastases. The aim of our study was to identify the predictors of lymph node involvement in breast cancer patients according to clinicopathological and genetic features of the primary tumour, which could help to avoid unnecessary lymph node dissection. Methods: Pathological reports of 175 breast cancer patients who underwent breast surgery in V.I.Kulakov RC for OGaP were retrospectively reviewed. Univariate analysis and multivariate logistic regression were used to analyse the correlation between lymph node metastasis and clinicopathological and molecular characteristics of the primary tumour. The included patient age, multi/unifocal growth, laterality and quadrant localization, tumour size, histological type, grade, Integrated Pathological Index (IPI), number of resected lymph nodes, ER- and PR-status, HER2-status, Ki67 index, molecular subtypes and 48 genes. Results: Tumour size (p=0.0026), IPI (p‹0.001), CCND1 (p=0.021), SCGB2A2 (p=0.022), FOXA1 (p=0.025), FGFR4 (p=0.027), AR (p=0.048), PTEN (p=0.049), TMEM45B (p=0.049), CCNE1 (p=0.05) were the most powerful predictors of axillary lymph node metastases. There was no statistically significant correlation between regional lymph node metastasis and age, tumour localization, molecular subtypes, hormone receptor- and HER2-status and other 40 genes. Multivariate logistic regression of significant variables was used to create a nomogram. Conclusion: Size of the primary tumour, IPI and 8 genes (CCND1, SCGB2A2, FOXA1, FGFR4, AR, PTEN, TMEM45B, CCNE1) are independent predictive risk factors of axillary metastasis in breast cancer. This work was sponsored by grants from the National Natural Science Foundation of Russia (АААА-А18-118053190016-7). E-PS-02-044 Mucoepidermoid carcinoma of the breast with MAML2 gene rearrangement: a case report D. Gigliano 1 , M. Farinha 1 , J. Vieira 1 , N. Coimbra 1 , C. Leal 1 1 IPO-Porto, Portugal Background & Objectives: Mucoepidermoid carcinomas (MEC) are the most common malignant neoplasms of both major and minor salivary glands. Occasionally, they may occur in other sites such as lacrimal glands, thyroid and, very rarely, breast tissue, with less than 40 cases of breast MEC described in literature. Given their rarity, grading and management are frequently controversial. Methods: We report the case of a 15-years-old female with long-standing serosanguineous nipple discharge and a 9mm hypoechoic breast nodule detected by ultrasound. The core biopsy of the nodule, performed in another hospital, resulted in a diagnosis of invasive carcinoma, with features of secretory carcinoma. Once transferred to our Institution, an MRI scan detected a smaller additional nodule. A second core biopsy was performed in this smaller nodule, while the slides from the first biopsy were reviewed. Results: The morphological features of the two nodules were overlapping, both being evocative of salivary gland-like breast carcinomas. Our main diagnostic hypotheses were MEC and secretory carcinoma. Immunohistochemical characterization revealed a ER-, PR-, HER2-, p63+, CK14+ and CK5/6+ phenotype. FISH analysis revealed MAML2 gene rearrangement in 76% of the cells, while no translocations involving the ETV6 gene were found. Based on these findings, a diagnosis of low-grade MEC was rendered. Three years after conservative surgery, the patient is healthy and disease-free. Conclusion: MEC of the breast is an exceedingly rare neoplasm with distinct morphological and molecular features. Genetic studies, along with morphology and immunohistochemistry, are an essential aid in the differential diagnosis of salivary gland-like breast carcinomas. E-PS-02-045 Male breast carcinoma in a Romanian series of cases O.C. Voinea 1 , A. Dumitru 2,3,4 , T. Georgescu 2,3,4 , M. Sajin 2,3,4 1 CCSMM, Romania, 2 SUUB, Romania, 3 UMF Carol Davila, Romania, 4 European Society of Pathology, Romania Background & Objectives: Breast malignancies are the most important generators of morbidity and mortality among women worldwide. Considering its frequency, impresive advances in diagnostic and therapeutic options were made. Being sporadic among male’s oncologic lesions, no standardised protocol exists, either for diagnostic, follow up or treatment. All these aspects are borrowed from pathology and oncology guidelines dedicated to female breast cancer. Since the importance of hormonal expression in this type of lesions is universally recognized, we believe that male breast lesions, taking into account it’s much worst prognostic and stage at presentation than in women, deserves further studies for a superior approach. Methods: We present our experience with male breast cancers in a retrospective review series of cases from Pathology Department of University Emergency Hospital Bucharest. Histopathological examination was completed with clinical information and the immunohistochemical expression of several markers was assed. Results: We identified 6 male breast carcinomas, four of which were encountered in 5 th , 6 th and 7 th decade and the other 2 in young adults (35 and 40 years old). In a single case 2 different breast carcinoma histotypes were found. All of them were G2, with tumoural stages varying between IB to IV. Several hormonal receptors, Ki 67 and HER2 were tested and expressed in each case, in different percentages. Conclusion: Male breast carcinoma is a rare entity with a poor prognostic, with a diffuse and profound invasion of adjacent structures, with a high expression of hormone receptors and with no histologic relation to gynecomastia, considering that no associated benign lesions were found. E-PS-02-046 Characterisation of fluorescence signals chromosome 17 centromere in epithelial cell breast ducts D. Chuglova 1 , A. Murashkina 1 , A. Kudaybergenova 1 , V. Kushnarev 1 1 N.N. Petrov National Medical Research Center of Oncology, Russia Background & Objectives: Normal epithelial cells used as internal control for HER2 in situ hybridization tests for its validity. This study aimed to investigate the morphology of nucleus and fluorescent signals of chromosome 17 centromere (CEP17) in adjacent to invasive carcinoma breast ducts in patients with intermediate (2+) HER2 cases. Methods: We randomly selected 5 cases of invasive breast cancer without any treatment with non-cancer adjacent ducts on slides and performed fluorescent in situ hybridization (FISH) assay for HER2 amplification. Slides were scanned by Pannoramic 250 (3D Histech) and were assessed by manual tool selection of nuclei and fluorescence signals by annotations on whole slide images. Results: We quantified 200 non-overlapping nuclei. Mean area of non-cancer nuclei by DAPI was 46,25± 11,5 μm2 (compare 78,4±.16,08 μm2 in cancer cells). Distribution of the fluorescent signals from HER2 gene and CEP17 in non-tumour breast duct epithelium were to red signal: 1,9±0,4; to green signal: 2,1±0,3. Conclusion: Normal distribution of CEP17 and parameters of fluorescent signals of gene HER2 is a key feature for analysis of diagnostic test. Pathologist has to know basic morphological parameters of probe and nuclei. E-PS-02-047 Programmed death-ligand 1 expression in triple negative breast cancer M. Bogdanovska Todorovska 1 , G. Petrushevska 1 , V. Janevska 1 , L. Spasevska 1 , S. Kostadinova Kunovska 1 , R. Jovanovic 1 , B. Krsteska 1 , A. Eftimov 2 , S. Komina 1 , P. Zdravkovski 1 1 Institute of Pathology, Medical Faculty, Skopje, Assistant professor, Republic of North Macedonia, 2 Pharmacist/ Institute of Pathology, Medical Faculty, Skopje, Republic of North Macedonia Background & Objectives: Triple negative breast cancer (TNBC) account for 10-20% of all breast subtypes and are associated with poor prognosis. There is no approved targeted therapy for these patients, yet. Programmed death-ligand 1 (PD-L1) expression has been identified in different cancers achieving good results with immunotherapy. There is limited data reporting the PD-L1 expression in TNBC. The aim of this study is to evaluate the expression of PD‑L1 in TNBC patients and to analyse the relationship between PD‑L1 expression and clinicopathological features of the patients. Methods: Paraffin tissue blocks from 19 TNBC patients were used. PD-L1 immunohistochemistry was performed using monoclonal mouse anti-PD-L1, Clone 22C3. Expression of PD-L1 was correlated with clinicopathological features. Tumours were defined as PD-L1 positive if there was membranous expression in ≥ 1% of tumour cells. Results Median age at diagnosis was 56 (range 33-74). PD-L1 was expressed in 7 (36, 8%) of the patients. Six of the patients showed low PD-L1 expression (3-20%) and only one patient showed high expression (>50%). The PD-L1 expression showed no significant correlation with clinicopathological parameters. Although statistically not significant (p>0,05), PD-L1 was more often expressed in high grade tumours with larger size, high clinical stage and mutated p53. Conclusion: Expression of PD-L1 was found in more than one third of TNBC and correlated with poor prognostic factors. PD‑L1 may be a significant marker for predicting prognosis of TNBC patients. These data need to be confirmed in larger study group. E-PS-02-048 Adenomyoepithelioma of the breast: a case report with review of literature L.E.B.F. Luísa Brochado Ferreira 1 , M. Marques Oliveira 1 , R. Amorim 1 , C. Estima Fleming 1 , B. Fernandes 1 , J.R. Brandão 1 , N. Lamas 1 , J. Raposo Alves 1 , J. Ramon Vizcaino 1 1 Centro Hospitalar e Universitario do Porto, Portugal Background & Objectives: Adenomyoepithelioma of the breast is an uncommon tumour characterised by biphasic proliferation of myoepithelial cells around epithelial-lined spaces. A spectrum of histologic patterns may be present, even in different areas of the same tumour. Because of this heterogeneity, these lesions can be diagnostically challenging. Although most tumours usually behave indolently, rare cases have a more aggressive course. For this reason, failure to recognize this entity may lead to inappropriate diagnosis and management. Hence, accurate diagnosis, and adequate excision followed by close follow-up is mandatory. Methods: A healthy 25-year-old woman, without family history of breast cancer, had a palpable right breast mass. The mammogram showed a heterogeneous nodule, predominantly solid, with cystic areas, and apparently surrounded by a capsule, with 26.7x14.8 mm in greatest dimensions. A 35×25×15 mm nodule was removed. The nodule was composed by areas of elastic tissues with vaguely multinodular appearance and microcystic/cystic areas. Results: Histologically, the tumour was constituted by a proliferation of myoepithelial cells, surrounding small epithelial ducts, and presented paucicellar estroma. The myoepithelial cells were cuboid, with abundant, clear and foamy cytoplasm, bulky nuclei with fine chromatin and small nucleolus. About 12 mitoses / 10 large magnification fields were documented, essentially in the myoepithelial component. No significant atypia, infiltrative growth pattern, desmoplasia or necrosis was identified. Conclusion: Adenomyoepitelioma is a relatively rare benign breast tumour with potential for recurrence, malignant transformation and metastasis. The lesion may be morphological heterogeneous, and has potential to mimic other benign or malignant lesions of the breast, therefore posing a diagnostic challenge. E-PS-02-049 Pathological features of the structure of the endoprosthesis capsule. Complications reconstructive breast surgery. Look at the pathologist N. Volchenko 1 , I. Shirokih 1 , M. Yudakova 2 , V. Surkova 1 1 Moscow Oncology Research Institute - Branch of the National Medical Radiology Research Centre of the Ministry of Health of the Russian Federation, Russia, 2 Multidisciplinary Medical Center of the Bank of Russia, Russia Background & Objectives: The installation of a tissue expander or implant immediately after a mastectomy is the most often used method of breast reconstruction. According to American Society of Plastic and Reconstructive Surgeons, currently The share of simultaneous breast reconstruction is more than 70%. In Australia it increased by 9.9% from 1982 to 2000, in Denmark by 14% from 1999 to 2006, in England - by 16.5% from 2006 to 2009 (Platt J., Baxter N., Zhong T. Breast reconstruction after mastectomy for breast cancer. CMAJ 2011). In our work, we analysed the complications of breast reconstruction: • Textured endoprostheses • Polyurethane endoprostheses • Simultaneous reconstruction of the endoprosthesis with additional shelter mesh implant • Simultaneous reconstruction of the endoprosthesis with additional shelter acellular dermal matrix (ADM) Permacol (porcine) Methods: In our study, 79 (50.31%) observations used an implant with polyurethane coating, 78 (49.68%) used an implant with a textured coating. Morphological study of the formed endoprosthesis capsule was held in terms of 12 months. after operation. (Pic.1,2,3,4)A morphological assessment of the endoprosthesis capsules with various variants of the endoprosthesis coating (ADM and mesh implant). Installed 30 endoprostheses with a sheath of ADM flap, 2 flaps were examined. Morphological examination of the formed endoprosthesis capsule using ADM, as well as net implant was performed for 14 months. after surgery sharp extrusion of the endoprosthesis (Fig. 5, 6). ADM (cell-free dermal matrix) Biological implants, or cell-free dermal matrix (ADM) - donor skin flap, by special treatment, devoid of its antigenic properties In Russia it is allowed to use ADM Permacol pork. Mesh implants (Fig. 7, 8). • Strengthening the lower slope of the reconstructed chest • Creation of additional space for a muscle pocket • Full endoprosthesis shelter • reasonable material cost Results: 1. Using polyurethane endoprostheses has several advantages. • During healing, dense connective tissue grows into the surface. The implant is held firmly in place preventing it from dropping • Eliminates the displacement outward, as well as the rotation of the anatomical implant. • Netting of a fiber capsule similar to a grapevine (with smooth and textured fiber implants arranged in parallel surface). The structure of the capsule in the form of a lattice prevents its reduction, thereb reducing the occurrence of capsular contracture Microscopic view of the capsule: • A characteristic microscopic feature is the presence of triangular polyurethane crystals, which are formed over time during resorption polyurethane foam endoprosthesis. (Fig. 9) • The fibrous capsule consists of a set of tightly bound tissues that randomly intertwined. (pic.10) • According to our histological data, despite the claimed advantage polyurethane coating, in the form of reducing the occurrence of contractures, polyurethane triangular structures cause productive inflammatory the reaction with the presence of giant multi-core cells "type of foreign body", which leads to fibrosis and hyalinosis of the capsule tissue, thereby increasing percentage of occurrence of contracture. (fig.11,12) 2. Microscopic view of the capsule of a textured endoprosthesis: • The fibrous capsule is constructed of dense connective tissue, the fibers of which are located relatively parallel to the surface of the implant, which reduces its extensibility and increases the percentage of fibrous contracture (fig. 13,14) • In the fibrous capsule along the inner surface, the pseudo-synovial membrane, as it turned out, it occurs twice as often, of varying degrees of severity, in contrast to capsules with polyurethane implants. Psevdosinovialny overlay leads to the formation of fluid between the implant and the fibrous capsule (seroma). (Fig.15,16) • Inflammatory changes in the fibrous capsule of a textured implant. Severe lymphoid infiltration with the presence of xanthoma cells, which also results to the expressed fibrosis and hyalinosis of the tissue of the capsules and, as a result, to contracture. (Fig.17,18) 3. ADM (cell-free skin matrix) • Microscopic examination of the endoprosthesis capsule with ADM did not reveal pronounced formation of pseudo-synovial membrane, productive • The inflammatory reaction was found mainly in the thinned skin. flap (in the reticular and papillary dermis), and in the ADM flap itself is productive inflammation markedly weak. The synovial membrane in the flap examined is not detected (fig. 19, 20). 4. Mesh implants: • Morphological assessment of endoprosthesis capsules with the presence of a mesh implant in patients after extrusion of the endoprosthesis Rapid germination (large-pore the mesh design fills a three-dimensional collagen fiber mesh, which reduces risk of contracture) (Fig. 21,22) Conclusion: Complications occurring in patients after endoprosthetics depend on the type capsules formed around the implant, which in turn depends on the type of endoprosthesis or additionally covering it. In the case of polyurethane endoprostheses, complications such as pronounced productive inflammation ("red syndrome"), appear in the first place, contractures are formed in second place, and the third place is the formation of seroma. With a textured implant: the formation of contractures, seroma different severity, inflammatory changes. When using additional ADM closing valves and nets, complications such as contractures and formation of seromаs are extremely rare. This technique is used, as a rule, with a small pinch test, the most frequent A complication in this group of patients is the protrusion of the implant and the addition of pronounced nonspecific inflammation. Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-03 | Cardiovascular Pathology Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-03 | Cardiovascular Pathology E-PS-03-001 Hydatid cyst of the heart, fatal evolution, a case report Z. Merad 1 1 CHU Sidi Bel Abbes, Algeria Background & Objectives: The hydatid disease remains a public health problem. However, the cardiac hydatid cyst is rare (0.5-2%). The objective of the work: is to report the rarity of this lesion Methods: We report a case of cardiac hydatid cyst for a man of 50 years, presented with syncope clinically Results: A chest roentgenogram showed big enlargement of the cardiac silhouette with deformation of the left arch. The electrocardiogram revealed the presence of the complete right bundle branch block. The ultrasound cardiac showed a cystic mass fluid in the left ventricle. The extracardiac locations were excluded after completion of a comprehensive review. The patient died after refusing the surgical treatment. The macroscopic and microscopic study has confirmed the diagnosis of cardiac hydatid cyst Conclusion: Cardiac localisation of hydatidosis is rare. Polymorphism Clinical, latency and severity of complications are the essential features. The treatment is essentially surgical. Medical treatment is limited to disseminated and non-operable forms. The eradication of this condition in endemic countries requires effective prevention. E-PS-03-002 Morphological features of the peripheral arterial occusive lesions in diabetic patients with critical limb ischemia B. Magrupov 1 , S. Temirov 2 , V. Ubaydullaeva 3,1 , T. Kamalov 4 , B. Tursunov 2 1 Tashkent Institute of Postgraduate Medical Education, Uzbekistan, 2 Central hospital of the ministry of internal affairs, Uzbekistan, 3 Republican Research Center of Emergency Medicine, Uzbekistan, 4 Republican specialized scientific and practical medical center of endocrinology, Uzbekistan Background & Objectives: Critical limb ischemia (CLI) is one of the severe complications of diabetes mellitus (DM). An assessment of the morphological changes of the arteries may help clarify the causes of the aggressive course of the process in the peripheral arteries in patients with DM. The object of this work was to study the morphological changes in the peripheral arteries in the diabetic patients with critical ischemia. Methods: A morphological analysis of the arteries of the amputated lower limbs was carried out in 14 patients with DM. Specially prepared fragments of arteries were studied under a light microscope, and their morphometric study was also conducted. Results: In 12 cases of 14 the calcification of the middle layer of anterior tibial artery occurred in different severity, in 6 there was a thickening of the intimal due to the accumulation of cholesterol and proliferation of smooth muscle cells. In the posterior tibial artery, in 11 cases, calcification of the middle layer in different severity was detected. In 5 cases, an intimal artery thickening due to the atheromatosis was observed and similar lesions were observed in the peroneal artery. Conclusion: Peripheral arterial lesions in patients with DM are not a purely atherosclerotic process. Considering the presence of middle layer calcification, it probably necessary to review the algorithm of pharmacological therapy in diabetic patients with peripheral arterial occlusive lesions, taking into account the disturbance of mineral metabolism. E-PS-03-003 Giant cell myocarditis associated with immune checkpoint inhibitor treatment for metastatic renal cell cancer A. Bdioui 1 , K. Amemiya 1 , P. Bruneval 1 1 Hopital Europeen Georges Pompidou, France Background & Objectives: Myocarditis represents a severe complication of cancer immunotherapy. Lymphocytic-type myocarditis has been constantly reported in this setting. Giant cell myocarditis (GCM) is rare and characterised by a specific histopathology showing giant cells and by inexorable outcome leading to cardiac failure whatever the treatment. We report a case of GCM occurring during immune checkpoint inhibitor treatment. Methods: A 53-year old male patient had nephrectomy for renal cell carcinoma in October 2013. From December 2017 to January 2019, he received 27 cycles of nivolumab, an anti-PD1 antibody, inducing partial metastasis regression without complications. In January 2019 he was admitted for rapidly progressive cardiac failure (Normal coronary angiography; Ejection fraction at 36%, global hypokinetic left ventricle, and edema at echocardiography and MRI; Troponin T at 5,800 □g/L). Results: Endomyocardial biopsy showed GCM with extensive myocyte necrosis. Viral molecular study was negative. Nivolumab was stopped. Intravenous methylprednisolone pulses were given, followed by tapered oral. Cardiac failure, imaging, and biological parameters improved in a few weeks allowing discharge from the hospital. Although we cannot definitely rule out coincidence of immunotherapy and occurrence of a rare type of myocarditis, this case of GCM is very unusual since cardiac failure, biological and imaging parameters improved under steroid treatment and withdrawal of nivolumab. Conclusion: This suggests two hypothesis: 1- GCM could be a second type of myocarditis complicating immune checkpoint inhibitors besides lymphocytic myocarditis; 2- Autoimmunity could be involved in this puzzling type of myocarditis in which so far no viral or immune mechanisms had been documented. E-PS-03-004 Atresia of common pulmonary vein (ACPV) of fetus: an autopsy analysis D. Chen 1,2 , J. Shang 1,3 , W. Fang 1,3 1 Department of Pathology, China, 2 Beijing Anzhen Hospital, Capital Medical University, China, 3 Beijing Anzhen Hospital, Capital Medical University, China Background & Objectives: Objective to investigate pathologic manifestations of atresia of common pulmonary vein (ACPV) of fetus by autopsy. Methods: Three pathological specimens of atresia of common pulmonary vein of fetus were studied and who had been found by using echocardiography. Results: Of the 3 casesone was of complete and two were of incomplete atresia of common pulmonary vein. 3 cases were associated with total anomalous pulmonary venous drainage (TAPVD). They also had other complex congenital heart disease and associated with visceral heterotaxy and asplenia. It was different from infant that the fetus was not associated with pulmonary lymphangiectasis. Conclusion: ACPV is an extremely rare congenital heart disease. It is even more difficult to establish a diagnosis of ACPV if not associated with pulmonary lymphangiectasis. E-PS-03-005 Complex characteristics of various of the heart different forms myocardial infarctions V. Ubaydullaeva 1,2 , B. Magrupov 2 1 Republican Research Center of Emergency Medicine, Uzbekistan, 2 Tashkent Institute of Postgraduate Medical Education, Uzbekistan Background & Objectives: Coronary heart disease remains one of the topical diseases of medicine, connected mortality its prevalence and a stable first place in the structure of the able-bodied population in most countries of the world. Currently more than 20 risk factors of coronary heart disease have been identified. Atherosclerosis is one of the main causes of coronary artery disease. Methods: A complex morphological and morphometric study of the heart muscle in 247 patients who died from various forms of myocardial infarction (MI) was carried out. Myocardium for morphological investigation from the following area was taken the necrosis zone border zone 2 cm from the necrosis area, opposite to the necrosis of the left ventricle (LV) and the right ventricle (RV) walls. Sections were stained with hematoxylin and eosin, pikrofuksinom, Schiff's reagent. Frozen sections were stained with Sudan III. Results: The zone of necrosis expanded during the first 72 hours. In the zone bordering the infarction, changes interstitial to the necrosis zone were with observed 8-12 hours delayed. At a distance of 2 cm. there were dystrophic, edema. Perivascular edema, vascular plethora were noted in the opposite of the infarction wall of the LV, RV. Conclusion: At recurrent and continuous recurrent MI a pathological process is more extensive and dystrophic changes along the periphery are more apparent. An increase of the heart with a predominance of width over length, an increase in mass by more than 200 grams, and a restructuring of the cardiac tracts corresponding should be considered as the risk limit for MI development. E-PS-03-006 Myocardium: structure-functional relationship V. Zakharova 1,2 , E. Trembovetskaya 2 , A. Balabai 3 , E. Rudenko 2 , T. Savchuk 3 1 Ukrainian Society of Pathologists; International Academy of Pathology, Ukraine, 2 Amosov National Institute of Cardiovascular Surgery, Ukraine, 3 Bogomolets National Medical University, Ukraine Background & Objectives: The Torrent-Guasp theory about unique myocardial band contradicts the data of histological and functional studies. In 2018 a group of authors from 10 universities published 2 articles in which they debunked this concept. But the question, how the myocardium provides a complex trajectory of heart movement, needs further study. Objective: to study the role of myocardial architecture in the formation of a complex trajectory of the heart left ventriculum (LV) movement. Methods: Macroscopy: 10 boiled prepared pig hearts. Microscopy: serial histological sections of 16 fetal hearts (abortion at 20-21 weeks of gestation due to medical reasons, not related to the heart pathology): 10 hearts were cut across, 3 - in the frontal and 3 - in the sagittal planes. LV mechanics were studied in 35 healthy young volunteers using speckle tracking echocardiography. The longitudinal displacement, rotation angles and degree of myocardial deformation were evaluated for each of 17 myocardium segments. Results: The apex of the heart rotates counterclockwise by 12,5±1,1°, the basal segments – clockwise by 8,3±1,4°. The median LV part doesn’t rotate, but moves most of all radially. Basal segments show the maximal longitudinal displacement, apical – minimal, apex - maximal deformation. Myocardium is 3D-cardiomyocytic network, the compact layer of which at the base and apex turn into trabeculae, forming a closed contour. There are bundles in it, the direction of which corresponded to the segmental trajectories of LV movement. Conclusion: Systolic movement of LV myocardium is provided by a consolidated contraction of its different segments in the longitudinal, radial and circulatory directions. The motion vector of each myocardial segment depends on the orientation of its muscle fibers and their contractions sequence. Trabeculae contract first of all and therefore they are initial fulcrum for cardiomyocytes of the compact myocardium. E-PS-03-007 HSP70 overexpression in calcified aorta affected by atherosclerosis A. Romaniuk 1 , I. Radomychelski 2 , M. Lyndin 3 , A. Piddubnyi 1 , V. Sikora 3 , M. Baumann 4 , R. Moskalenko 1 1 Sumy State University, Ukraine, 2 Sumy State University, Department of Pathology, Ukraine, 3 Sumy State University, Medical Institute, Department of Pathology, Ukraine, 4 Internistische Fachklinik Dr. Steger Ag, Germany Background & Objectives: High levels of HSP70 appear to have atheroprotective effect. It was reposted, that antibodies to HSP70 were increased in patients with vascular disease. Also HSP70 levels correlate with lesion severity. Aim of the investigation was to study the HSP70 expression in aortic tissue with calcifications affected by atherosclerosis. Methods: We examined 30 samples of mineralized aorta with calcifications (group I) and 10 samples of aorta wall tissue without any signs of biomineralization (group II). The group II was considered to be a control group. Histological and immunohistochemical methods were used during the study. Samples were fixed, embedded in paraffin, and analized for HSP70 accumulation using the anti-HSP70 antibody, followed by DAB detection substrate and counterstained with Mayer’s hematoxylin. Results: HSP70 expression was increased in aortic tissues with calcifications (23.4±1.28 cells per 1 mm2) in comparison to those without them (11.5±1.14, p<0.001, Student test). HSP70 was mostly localized in cells cytoplasm of macrophages, fibroblasts, endothelial cells and smooth muscle cells, also in the tissue around the calcifications. Conclusion: Overexpression of HSP70 was found in several cell types in aortic mineralized tissue affected by atherosclerosis may be regarded as its involvement in the formation of such biominerals. E-PS-03-009 Angiosarcoma developing in dialysis-related arteriovenous fistulae: two cases with review R. Almeida 1,2 , H. Moreira 1 , J. Fraga 1 , B. Pimentão 1 , A. Lai 1 , V. Almeida 3 , C. Faria 1 , F. Ramalhosa 1 , R.C. Oliveira 1 , V. Sousa 3 , M. Julião 1 , M.A. Cipriano 1 1 Centro Hospitalar e Universitário de Coimbra - Pathology department, Portugal, 2 Faculty of Medicine in Coimbra, Portugal, 3 Institute of Anatomical and Molecular Pathology, Faculty of Medicine of the University of Coimbra, Coimbra, Portugal, Universitário Background & Objectives: Arteriovenous fistula (AVF) is the first method considered for vascular access in patients with renal failure, who require or may require renal dialysis. Recent studies suggest that AVF should not be ligated post-transplant, except in cases of ischemia, infections or aneurysms. Angiosarcoma in AVF is a very rare complication in non-functioning fistulae, usually after transplant. Typically, presents as an enlarging painful lesion of several months duration, and such conditions should raise concern about this entity. Methods: A retrospective research at Coimbra Hospital and Universitary Center, over a period of 15y, revealed two cases of angiosarcoma in AVF. A 82y-old male under hemodialysis, presenting a 4,5cm painful mass in the right arm, growing over a non-functioning AVF. A 54y-old female with history of renal transplant 15y before, with a pulsatile subcutaneous lesion in the left arm, 9,5cm, clinically diagnosed as an aneurysm of a non-functioning AVF. Both patients were submitted to excisional surgery. Results: Histology showed ulcerated neoplasias with deeply infiltrating borders, compromising the surgical margins, composed of epithelioid cells, with solid growth and focal vascular-like pattern. Neoplastic cells were vimentin and vascular markers - CD31, CD34, ERG and Fli-1 - positive, without staining for keratins. The male patient died 6 weeks after surgery, and the female patient has no known relapse until the moment of submission (1 month after surgery). Conclusion: Angiosarcoma is a rare mesenquimatous neoplasia, deeply invasive with a very aggressive behavior, and a low disease-free survival. The aim of this work is to warn physicians about the developing of angiosarcoma in AVF, particularly in immunosuppressed patients, commonly after transplant. E-PS-03-0010 Mitral valve caseous calcification with interventricular involvement: presentation of two cases S. Papadodima 1 , J.R. Stone 2 1 Department of Forensic Medicine and Toxicology, National and Kapodistrian University of Athens, Greece, 2 Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA USA Background & Objectives: Caseous calcication of the mitral annulus (CCMA) is a rare variant of mitral annular calcification. Extension of mitral caseous calcification along the fibrous skeleton of the heart is extremely rare. We report two cases in which an extensive involvement of the interventricular septum was revealed during the pathological examination. Methods: A retrospective analysis of the pathology database of Massachusetts General Hospital during the period 2010-2015 was performed in order to identify cases with CCMA with interventricular septum involvement. Results: Two cases were identified. Case 1. An 83-year-old man underwent surgical aortic valve replacement. During the surgery, the bicuspid aortic valve was found to be heavily calcified. A large amount of calcium with an area of liquefaction within the interventricular septum was observed, and a septal myectomy was performed. Pathologic examination of the interventricular septum revealed patchy calcification with areas of caseous calcification. Case 2. A 70 year old female died on the third postoperative day after aortic and mitral valve replacement, left atrial appendage amputation, and decalcification and pericardial patch repair of the mitral annulus. Gross examination of the heart revealed two well-circumscribed, soft, white mass lesions in the interventricular septum focally abutting the mitral valve, which upon histology showed caseous calcification. Conclusion: CCMA is often considered a benign process; it is usually asymptomatic and an incidental finding. However, in the case of interventricular septum involvement, it may cause several conduction system disorders. Such interventricular septum involvement may be misinterpreted as a neoplasm on imaging, prompting unnecessary surgery. E-PS-03-011 Cardiac Fibroma in 4-month-old infant: a case report D. Anestakis 1 , I. Leonida 1 , E. Petrou 1 , C. Leonida 1 , E. Chatzifotiou 1 , E. Zagelidou 2 1 Department of Autopsy Histopathology, Lab. of Forensic Medicine and Toxicology, Aristotle University of Thessaloniki, Greece, 2 Thessaloniki Forensic Service, Thessaloniki, Greece Background & Objectives: Cardiac Fibromas are benign primary tumours of connective tissue, situated in the heart; especially in the ventricles or in the interventricular septum. The frequency of Cardiac Fibromas is higher in Paediatric population and ranges from 0.03-0.032% in the general population. We report a case about a sudden death of an infant with cardiac fibroma. Methods: The 4-month-old female passed away unexpectedly at home without previous hospitalization. There were no symptoms, but the autopsy examination of the cardiac tissue revealed three white-grey mattered masses composed of fibroblasts located in the ventriclescovering the largest part of the cavity. Results: According to the histological findings, in some parts of the masses were found homomorphous atractoid cells, disseminated and intertwined among collagen fibrils. There were rare inflammatory cell-clumpingsnear healthy tissue, elements of autolysis, median swelling, places of median fibrosis around vessels. There were places of fibrotic connective tissue inside the myocardium, locally myocardial fibers have waveform morphology, layout disorder, while there are inflammatory cells and capillaries with varying degree-thickened walls. There are locally ischemic lesions and presence of neoplasm, which looks like fibrosis. Conclusion: The diagnosis of primary cardiac fibroma is of great importance, because although is benign it might be fatal. The prognosis is poor if the fibroma is not surgically resectable. There is no prediction depended on sex or race. Cardiac fibrosis may cause heart failure, cyanosis, arrhythmias, syncope, chest pain or sudden death. E-PS-03-012 A rare cardiac benign tumour case report: papillary fibroelastoma T. Bolme Savli 1 , H.E. Pasaoglu 2 , T.C. Savli 3 , F. Emre 1 1 Bagcilar Training and Research Hospital, Turkey, 2 Clinical Pathology, Turkey, 3 Istanbul Training and Research Hospital, Turkey Background & Objectives: Papillary fibroelastomas are the third most common cardiac tumours after myxoma and lipoma. Papillary fibroelastoma is the most common tumours located on cardiac valves. Surgical resection should be offered to all patients who have symptoms and to asymptomatic patients who have pedunculated lesions or tumours larger than 1 cm in diameter. Methods: We report a 75-year-old male patient. A routine echocardiogram revealed small pericardial effusion, patent foramen ovale and 1.3x1.2x1 cm sized mobile cardiac mass attached to the aortic valve. Results: The tumour was surgically removed and histopathological examination confirmed the diagnosis to be a cardiac papillary fibroelastoma. Conclusion: Although cardiac papillary fibroelastomas are commonly detected incidentally, they can cause embolization and mortality. Since our papillary fibroelastoma case causes pericardial effusion and patent foramen ovale, we found it worth to present. E-PS-03-013 Leiomyosarcoma of the inferior vena cava and renal vein: a case report A. Ok Atilgan 1 , E. Yilmaz Akcay 1 , B. Ozdemir 1 1 Baskent University Faculty of Medicine Pathology Departmant, Turkey Background & Objectives: Leiomyosarcoma of the inferior vena cava is a rare mesenchymal tumour originated from smooth muscular fibers of the tunica media. They grow slowly and extend to the adjacent tissue. Methods: A 57-year-old-woman had developed an abdominal distention and pain during the last one year. Radiological imaging revealed a large mass in the left renal vein extend to inferior vena cava, suprarenal vein, and ovarian vein. Results: The patient underwent a left nephrectomy and resection of the vena cava inferior. Macroscopic analysis revealed a 13x7x6 cm diameter mass which was grown up an intraluminal extension of inferior vena cava, renal vein, suprarenal vein, and ovarian vein. Extraluminal extension into renal parenchyma, renal sinüs, renal pelvis was not seen. Cut surface of the tumour was gray-white, firm and whorled. In microscopic examination, the tumour showed hypercellular spindle cell with moderate to severe nuclear atypia, tumour cell necrosis, increased mitotic activity. Tumour originating from the wall of the renal vein and inferior vena cava was also observed. Immunohistochemistry showed strong positive staining for caldesmon, smooth muscle actin, and negative staining for CD117, DOG-1, S-100, CD34, Fli-1. Conclusion: Leiomyosarcoma of vascular origin was located in the larger vein, especially vena cava . The differential diagnosis includes angiosarcoma, leiomyosarcoma, intravenous leiomyomatosis, sarcomatoid renal cell carcinoma invasion, clinically and pathologically. Total surgical resection with negative margins of the tumour is the main treatment for leiomyosarcoma. E-PS-03-014 Calcified amorphous tumour of the heart: a case report C. Gkogkou 1 , V. Lozos 1 , E. Koniaris 1 , E. Nikolopoulos 1 , K. Tsiardis 1 , G. Kafiri 1 1 "Hippokratio" General Hospital of Athens, Greece Background & Objectives: Calcified amorphous tumour (CAT) is an exceptionally rare endocardial non-neoplastic mass of unknown pathogenesis that was first described in 1997. Since then less than fifty cases were reported in the literature. Here we present a case of CAT because of its rarity and the diagnostic challenges it poses predominantly on clinical level. Methods: A 75 year-old woman presented with recurrent ischemic strokes. Echocardiographic examination revealed a pedunculated mass attached to the posterior leaflet of the tricuspid valve. The lesion was excised and it was submitted for histological examination in three pieces. Grossly the pieces were whitish, solid and hard, with diameter ranging between 0.8-1.3cm. Results: Microscopically the lesion was composed of connective tissue and masses of fibrin with extensive calcification. The connective tissue lacked hypercellularity and cytologic atypia. A moderate number of foreign body multinucleated giant cells were also focally evident. There were no epithelioid granulomas, fungal hyphae, parasites or other cellular elements. Based on the above findings, the diagnosis of CAT was established. Conclusion: Patients with CAT are reported to present with non-specific symptoms, like dyspnea, arrhythmias or syncope. Clinical awareness of this rare entity is required, since its non-neoplastic nature may allow for a conservative management in some, mainly elderly patients. Excised masses should be thoroughly sampled to exclude the possibility of underlying granulomatous or neoplastic processes. E-PS-03-015 Brachial artery fusiform aneurysm with intimomedial mucoid degeneration in a young child - a case report of a rare entity N.J. Lamas 1 , M. Oliveira 1 , L. Ferreira 1 , C. Fleming 1 , R. Amorim 2 , J.R. Brandão 2 , B. Fernandes 2 , F.E. Costa 1 , D. Tente 1 , J.R. Vizcaíno 1 1 Anatomical Pathology Service, Department of Pathology, Hospital and University Center of Porto, Porto, Portugal, 2 Centro Hospitalar do Porto, Portugal Background & Objectives: Intimomedial mucoid degeneration (IMMD) is an extremely rare vascular disorder characterised by mucin deposition in both the tunica intima and media of arterial walls, with associated elastic tissue degeneration of both internal and external elastic lamina, leading to aneurysm formation. Methods: We report the case of a 4 year-old male child who had two bilateral brachial artery and right common iliac artery fusiform aneurysms detected at 12 months of age through magnetic resonance imaging. The patient has been under surveillance for nearly 3 years and recently underwent vascular surgery to remove the right brachial artery aneurysm since the presence of a thrombus was suspected. Results: A two centimeter tubuliform specimen was received, with fusiform morphology, having 3 mm diameter in the surgical ends and 8 mm diameter in the middle region. The external surface and the internal lining were smooth. The histological analysis showed a large caliber arterial wall with marked expansion of the intimal and specially medial layer secondary to the extensive extracellular deposition of mucin-like material (colloidal iron and PAS/Alcian blue positive stainings), with accompanying fragmentation of both the internal and external elastic lamina (emphasized using the Van Gieson elastin staining). Furthermore, we could not observe thrombus formation, inflammatory infiltrate, degenerative cysts, fibrotic areas or amyloid deposition in the wall (absence of congophilic areas or apple-green pigment under polarized light after Congo Red staining). A diagnosis of intimomedial mucoid degeneration of the brachial artery was made. Conclusion: This case illustrates the main features of this extremely uncommon cause of aneurysm formation. E-PS-03-016 A rare case of sudden arrhythmic cardiac death R. Henriques de Gouveia 1 , C. Cordeiro 2 , F. Corte Real 2 1 INMLCF & FMUC & CHLO, Portugal, 2 INMLCF & FMUC, Portugal Background & Objectives: Among Sudden Cardiac Deaths, Arrhythmic ones may be difficult to explain. The authors present a case with an unexpected cause. Methods: A 32 year-old male – with medical history of arrhythmia [suspicion of Wolf-Parkinson-White (WPW) Syndrome] for 12 years –, died suddenly during sleep, after a previous physical effort. Results: A thorough postmortem examination revealed cardiac pathology – “ Persistent Left Superior Vena Cava and Coronary Sinus Orifice Atresia ”. Conclusion: This congenital cardiopathy is rare, with 99 known cases reported, and may be associated to other cardiac malformations and/or rhythm / conduction disturbances, namely WPW Syndrome type. Being aware of these associations may facilitate antemortem diagnosis and directed therapeutic intervention. E-PS-03-017 Dystrophin Cardiomyopathy R. Henriques de Gouveia 1 , R. Anjos 2 , J.P. Neves 2 , S. Ramos 2 1 INMLCF & FMUC & CHLO, Portugal, 2 CHLO, Portugal Background & Objectives: Cardiomyopathy is a phenotypic manifestation of Dystrophinopathies . The authors present such a case. Methods: A 23 year-old male, with family and personal medical history of Dystrophinopathy, was submitted to heart transplantation due to cardiac failure. The native heart specimen was sent to anatomo-pathological examination. Results: Macroscopic and microscopic evaluation (complemented with histochemistry and immunohistochemistry) revealed a “Dilated Cardiomyopathy Dystrophin-Deficient”. Conclusion: The present case intends to draw attention to Dystrophin Cardiomyopathy, since with increased survival of dystrophinopathies’ affected persons due to therapy improvements and classic complications control, cardiac involvement (25% to 90%) has become an important cause of morbidity and mortality. E-PS-03-018 IgG4 related disease in heart valves T. Paavonen 1 , E. Niinimäki 2 , A. Mennander 3 , I. Kholová 4 1 Department of Pathology, Fimlab Laboratories and Department of Medicine and Life Sciences, University of Tampere, Finland, 2 Department of Anesthesiology, Southern Carelian Central Hospital, Lappeenranta, Finland, 3 Department of Cardiothoracic Surgery, Heart Hospital, Tampere University Hospital, Tampere, Finland, 4 Department of Pathology, Fimlab Laboratories and University of Tampere, Finland Background & Objectives: Immunoglobulin G4 (IgG4) related disease is a systemic disease involving various organs as well as vascular structures like aorta. There is rather limited data on IgG4-related disease in other vascular tissues for example heart valves. Methods: Sixty surgically resected heart valves were included (48 aortic and 12 mitral valves). There were 44 males and 16 females with a mean age of 60 years. There were 24 valves with endocarditis (19 acute endocarditis, 3 chronic endocarditis, and 2 healed endocarditis). Degeneration was the main diagnosis in 36 cases, of which 17 had significant inflammation without full criteria of endocarditis. Immunohistochemistry was performed using Ventana Lifesciences Benchmark XT Staining module. CD38/CD138, IgG and IgG4 were used as antibodies to identify IgG/IgG4 positive plasma cells. Results: Increased IgG4 positive cell infiltration was found in four patients. Two degenerative heart valves with IgG4 positive plasma cells fulfilled the generally accepted criteria of >50 IgG4 positive cells/HPF, one mitral and one aortic valve. However, also two other valves had >20 IgG4 positive cells/HPF. Conclusion: IgG4-related disease may impact heart valves and heart can be be the first presenting organ of systemic disease. E-PS-03-019 Structural changes in the myocardium in cases of sudden cardiac death in young males A. Sapargaliyeva 1 , K. Ospanova 2 , T. Zhakupova 2 , F. Galitskiy 2 1 Pathology Bureau of the city of Almaty, Kazakhstan, 2 Department of Forensic Medicine, Astana Medical University, Kazakhstan Background & Objectives: Mast cells (MC) are found in various tumour types, but their pro or antitumoural role in prostate carcinoma is still debated. There are divergent opinions regarding MC correlation with prognostic factors. There are also contradictory findings regarding correlations between MC number and Gleason score (GS) in needle biopsy samples and radical prostatectomy. Our aim was to evaluate the MC distribution and its correlation with prognostic factors. Methods: Ninety patients who underwent transurethral resection of the prostate (TURP) at Colentina Clinical Hospital between 2016-2018 were selected for this study. We generated multi-tissue blocks and stained mast cells immunohistochemically with tryptase. We evaluated the mast cells infiltrate density in peritumoural and intratumoural areas and correlate the data with GS. Results: The ages of patients ranged from 53 to 91 (median 71 years). There was no correlation between age and MC count. We found that higher MC counts correlate with lower prognostic group (p<0.05), similar to studies conducted on prostatectomy and in contrast with needle biopsy samples. We found a difference in MC counts from intratumoural areas comparative to peritumoural areas. GS was negatively correlated with intratumoural MC number (p<0.001). Conclusion: Higher MC number correlates with better prognosis suggesting that MC can be a reliable prognostic marker in prostate cancer. Differences in MC number in needle biopsy versus prostatectomy and TURP may be due to smaller stromal areas identified in the biopsies. MC may play a role in the relationship between stromal microenvironment and tumour cells and can be a potential target of effective antitumour strategies. E-PS-03-020 Hydrophilic polymer cardiac emboli: postmortem case report F. Filipello 1 , N. Ahmed 1 , C. Doglioni 2,1 , F. Sanvito 2 1 Vita-Salute San Raffaele University, Milan, Italy, 2 Pathology Unit, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, Milan, Italy Background & Objectives: Hydrophilic polymer emboli (HPE) are a possible complication of intravascular procedures and have been reported in heart and other organs. We describe two postmortem examinations of sudden cardiac arrest with histological features of HPE in myocardium. Methods: The first case (A) was a 44 year-old man, arriving in Emergency Department (ED) in cardiac arrest. He received cardiac catheterization with coronary stenting due to thrombosis of the anterior interventricular artery (IVA). No evidence of cardiac function recovery was recorded and, 24 hours later, expired. The second case (B), a 52 year-old man pacemaker assisted, arrived in ED with cardiac arrest in suspected myocardial infarction and died before any treatment was given or any clinical history was taken. Results: Postmortem examination of case A: the metal stents in the IVA were in place and patent. Acute infarction with prior ischemic events of the left ventricle were detected. Basophilic, amorphous material was present in the small vessels of the myocardium. Case B revealed two bare metal stents in the IVA occluded by thrombi and microscopic evaluation displayed amphophilic to basophilic, amorphous material in the intramyocardial vessels associated with inflammatory cell infiltrate with foreign-type giant cells in the left ventricle. Conclusion: Although HPE may not have been the ultimate cause of death, it is possible that they contributed to the clinical outcome of patients. At present, attention has been focused on this issue, nevertheless the role and the complications of myocardial HPE are poorly understood by clinicians and pathologists. E-PS-03-021 The new concept of the interstitium explains the microscopic features and pathogenesis of a case of hypertensive pneumopericardium K. Metze 1 , N.B. de Almeida 1 , F.A. Borges da Silva 1 1 State University of Campinas, Brazil Background & Objectives: Recently a new concept of the interstitial space has been created (Scientific Reports, 2018,8:4947). In this autopsy report of a patient with hypertensive pneumopericardium we want to show how this new theory helps to explain the morphologic findings and the pathogenesis of this disease. Methods: A girl of two months was hospitalized due to respiratory distress provoked by viral bronchiolitis. During mechanical ventilation she suffered a sudden decrease in oxygen saturation followed by cardiac arrest. Resuscitation attempts were unsuccessful. An autopsy was performed. Results: Macroscopic inspection revealed mediastinal emphysema. When opening the pericardium under water hypertensive pneumopericardium was seen. Microscopic examination showed many confluent “empty” spaces in the peritracheal and mediastinal connective tissue, as well as in thymus and lymph nodes, creating smaller or larger tissue islands. We interpreted these spaces as channels of air propagation.The pericardium revealed also these channels connected to those of the other mediastinal organs and terminating in myriads of microscopic submesothelial bubbles. Conclusion: The new concept of the interstitium postulates a widespread fluid-filled pre-lymphatic space within and between different tissues. We believe, that after a microscopy tracheal rupture mechanic ventilation injected pulsating air into the interstitium, until reaching the pericardial space. There the alignment of the interstitial space (parallel or oblique to the mesothelial surface) created and air-trapping mechanism, which caused the lethal hypertensive pneumopericardium. Supported by CNPq E-PS-03-022 Secondary cardiac lymphoma with unusual clinical presentation: a case report A. Saidi 1 , I. Msakni 1 , R. Hedhli 2 , N. Mansouri 1 , F. Gargouri 1 , A. Bouziani 1 , B. Laabidi 1 1 Pathology Department; Military Hospital for Instruction of Tunis, Tunisia, 2 Tunis El Manar University, Medicine School of Tunis Military Hospital of Tunis, Department of Pathology, Tunisia Background & Objectives: Cardiac lymphoma is an extra nodal lymphoma usually secondary to a disseminated disease. Primary cardiac lymphoma is a very rare malignancy defined as involving only the heart and/or pericardium or with limited extra cardiac involvement. It affects more frequently adult men and carries an overall poor prognosis. Cardiac lymphoma is predominately of B cell lineage with diffuse large B-cell lymphoma being the most common histological type. Cardiac lymphoma often involves the right heart, especially the right atrium. Epicardial and pericardial infiltration with pericardial effusion is typical. Clinically, and contrarily to primary cardiac lymphoma, generalized lymphoma involving the heart is rarely initially revealed by cardiac manifestations. When present, cardiac symptoms are most commonly associated with pericardial effusion and congestive heart failure. Arrhythmias and sudden heart death are not uncommon. We report a new case of cardiac lymphoma in a young female adult with an unusual clinical presentation. Methods: In a case of secondary cardiac lymphoma, the clinical and pathological parameters are studied and discussed. Results: We report a case of a 32 year-old female reporting dyspnea and multiple episodes of syncope. Echocardiography, CT scan and MRI reveal an ill-defined, myocardial infiltrating mass localized in the right atrium and associated with moderate pericardial effusion, bilateral ovarian involvement. However, no mediastinal adenopathy was seen. A suspected meningeal involvement was confirmed on cerebrospinal fluid pathological analysis. Grossly, the surgically removed cardiac lesion presented as a 5 cm large whitish firm multinodular mass. Histological examination revealed an undifferenciated malignant proliferation composed of diffuse sheets of large and atypical immunoblast-like cells. Multiples areas of tumour necrosis were found. The proliferation’s immunophenotype was characterised by CD20 positivity and the negativity of CK, CD3, CD30, CD117 (c-kit) and CD99. Thus, the diagnosis of cardiac diffuse large B-cell lymphoma was established. Treatment included systemic and intrathecal rituximab-based chemotherapy followed by autologous peripheral blood hematopoietic stem cell transplantation. The patient had however a lethal outcome. Conclusion: Although our patient was affected by generalized malignant lymphoma involving her heart, she had only cardiac symptoms at initial presentation which is unusual with this type of malignancies. Like the majority of cardiac lymphomas, diffuse large B cell lymphoma was the histological type encountered in our case. Even though being sensitive to chemotherapy, cardiac lymphoma keeps carrying a poor prognosis as attested by this observation. E-PS-03-023 On application of cardiac fish preparations in education and research of pathology E. Neu 1 , B. Rattel 2 , M. Michailov 1 , T. Plattner 1 , P. Birkenbihl 1 , T. Senn 1 , V. Foltin 3 , G. Weber 4 , D.G. Weiss 5 1 Inst. Umweltmedizin c/o ICSD/IAS e.V. Muenchen, Germany, 2 Amgen Res. Munich (Exec. Dir.) & IUM c/o ICSD/IAS e.V., Germany, 3 St. Elisabeth Univ., Bratislava, Slovakia, 4 Univ. Lxbg. and Vienna, Fac. Psychology (Dean), Austria, 5 Univ. Rostock, Inst. Physiology (Dir.a.D.), Germany Background & Objectives: In medical education&research are till today usual cardio-vascular preparations of frog, rat, rabbit,etc. An essential part of experiments with isolated angio-cardiac preparations could be replaced by fish organs. About pharmaco-physiological reactions of fish heart of salmo gairdneri is reported [1,3]. Now is given information about effects of xenobiotics leading to pathophysiological reactions. Methods: Isolated fish heart (atrium, ventriculus cordis) from rainbow-trout: Registration of spontaneous contractions (isotonic rec.) in Krebs-Henseleit-solution (n=120, p<0.05<0.01) [1]. Results: Atrium & ventriculus cordis generate spontaneous regular&uniform contractions (6-24°C). Ethanol (0.01-0.5%) and butanol (0.001-0.01%) transform regular contractions of atrium into burst-like ones. HgCl 2 10nmol/l also induce similar transformation with very long burst-duration. Inotropic effect is not changed. Cypermethrin 10μmol/l has similar effect, but with strong negative inotropic effect. Their differences in effects in fish ventriculus cordis are observed. Conclusion: Fish cardiac preparations could be used as sensitive indicator for xenobiotics in water. Further, fish preparations could reduce enormous application of animal organs in academic education&research (universities) as well as in pharmacological industry, leading to large animal protection. Ref. : 1. Neu, Weiss, Michailov et-al.: IUPHAR-1994-Montreal. Can.J.Phys.&Pham., p.164 (1994) 2. Neu, Michailov, Bauer et-al.: IUPS-2009-Kyoto. J.Physiol.Sci. Proc IUPS Vol.XXII Springer, p.249 (2009) 3. Michailov, Neu, Welscher et-al.: IUPS-2017-Rio de Janeiro, Abstract-Book ID977, Proc.XXIV (2017) DEDICATION for moral-scientific support 2018-1980/Nobel Laureates: Australia: Sir J.Eccles, Austria: K.Lorenz, Belgium: I.Prigogine, Canada: G.Herzberg, J.Polanyi, France: J.Dausset, J.-M.Lehn, Germany: M.Eigen, K.v.Klitzing, H.Michel, E.Neher, GB: Sir A.Hewish, B.Josephson, Lord A.Todd, India/USA: S.Chandrasekhar, H.B.Khorana, Japan: K.Fukui, Sweden: S.Bergström, B.Samuelson, USA: P.Anderson, J.Deisenhofer, D.Hubel, L.Pauling, E.Wiesel Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-04 | Cytopathology Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-04 | Cytopathology E-PS-04-001 Antigen stability of cells stored in in-house liquid-based cell medium U. Klopcic 1 , A. Kuhar 1 , N. Nolde 1 , V. Kloboves-Prevodnik 1 1 Institute of Oncology Ljubljana, Slovenia Background & Objectives: Our study was designed to test how long the antigen properties of cells stored in our in-house liquid based cell medium are retained and immunocytochemical (ICC) reactions for estrogen receptor (ER), MOC-31, CK AE1/AE3, CD45, Calretinin and Melanoma triple cocktail can safely be performed. Methods: Each of the ICC markers was tested on ten different cell samples. For each sample cytospins were prepared and fixed in methanol on the day of the sampling and then subsequently on the second, fourth, fifth and eight day of the sampling. Percentage of positive cells, intensity of ICC staining, background, counterstaining and morphology were evaluated on 300 tested slides. Each tested slide had its respective negative control. Assessment criteria were adopted from UK NEQAS ICC scheme. Results: Percentage of positive cells and intensity of ICC staining of CK AE1/AE3, MOC-31, CD 45, ER and Melanoma triple cocktail were similar even after eight days storage of cell sample in in-house liquid based cell medium, while the percentage of positive cells in Calretinin ICC stained slides dropped significantly after the fourth day. Background, morphology and counterstaining changes did not affect the percentage of positive cells and intensity of ICC staining. Conclusion: Cells stored in in-house liquid-based cell medium retained unchanged antigen immunoreactivity for at least four days in our series. The time period in which antigen immunoreactivity of cells stored in in-house liquid medium is still retained should be tested for each ICC marker individually. E-PS-04-002 Reliability of fine needle aspiration of thyroid gland A. Ilic 1,2 , D. Miljkovic 1 , M. Panjkovic 1 , J. Ilic Sabo 1,2 , Z. Vrekic 2 , M. Miladinovic 3,4 and T. Lakic 1,2 1 University of Novi Sad, Faculty of Medicine, Serbia, 2 Clinical Center of Vojvodina, Novi Sad, Center for Pathology and Histology, Serbia, 3 University of Montenegro, Faculty of Medicine, Montenegro, 4 Clinical Center of Montenegro, Podgorica, Center for Pathology, Montenegro Background & Objectives: Fine needle aspiration cytology of thyroid gland (FNAC) is a generally accepted, minimally invasive, fast and economical procedure that determines algorithm for treating nodular thyroid lesions. FNAC routine application has reduced the number of thyroidectomies. We analysed performed thyroidectomies and presence and reliability of preoperative FNAC of nodular thyroid lesions. Methods: Retrospectively, pathohistological reports (PH) of patients who underwent partial/total thyroidectomy in the period 2014-2018 were analysed at the Center for Pathology and Histology of the Clinical Center of Vojvodina. Patients with preoperative FNAC were marked and analysed. Results: In five-year-period, 395 thyroidectomies were performed with female predominance. The average age was 51. The preoperative FNAC was found only in 10.9% of the total number. The positive correlation of FNAC and PH findings was registered in 84.7% of cases with 73.3% sensitivity. False positivity was present in 26.6% cases, while false negativity in 42.9%. Positive predictive value was registered in 47.8% and negative predictive value in 80% cases. AUS category consisted of 20% malignant and 80% benign PH diagnoses. Conclusion: FNAC of thyroid gland is accurate method which remarkably reflects the biological nature of thyroid lesion providing faster, less expensive and more reliable diagnosis of thyroid solitary nodes than any other clinical and laboratory tests. The main problems are caused by inadequate or borderline aspirates of the thyroid node and taking inadequate material without the diagnostic cells in the smear. E-PS-04-003 Pleomorphic carcinoma of the lung: diagnostic utility of fine needle aspiration K. Kuan 1 , S. El Hussein 1 , S. Khader 1 1 Montefiore Medical Center/Albert Einstein College of Medicine, Department of Pathology, USA Background & Objectives: Pleomorphic carcinoma of the lung is an exceedingly rare tumour that has only been recognized recently and classified by the World Health Organization in 2015. As its incidence only makes up to 0.4% of all lung malignancy, few studies are done on this entity. Here we present a case of metastatic pleomorphic carcinoma diagnosed with fine needle aspiration (FNA). This case report aims to highlight the cytologic features of this tumour and correlate them to its histological counterparts. Methods: A 70-year-old, female who is chronic smoker was found to have a mass in the right lung and subsequently underwent right pneumonectomy. Histological examination revealed the tumour to be pleomorphic carcinoma of the lung. Despite being on intense adjuvant chemotherapy, the disease still progressed. An ultrasound-guided FNA was performed later on an enlarged peri-pancreatic lymph node. Diagnosis of the FNA was made based on the cytomorphology of specimen and ancillary studies including immunohistochemical (IHC) stains and genetic testing were performed. Results: The tumour cells from both the surgical specimen and the FNA biopsy showed poorly differentiated glandular structures admixed with undifferentiated epithelioid cells and giant cells. Although the IHC stains of surgical specimen were positive for TTF-1, Napsin 1, they were not expressed in the cell block from FNA. Follow-up molecular study, however, identified the same EGFR mutation at exon 18 (719 G>X) in both sample. This finding greatly supported the diagnosis of metastatic pleomorphic carcinoma from the known lung primary. Conclusion: Pre-operative diagnosis of pleomorphic carcinoma of the lung can be very challenging, in part because of the scarcity of cases describing this entity on surgical biopsies or FNA biopsies. This case beautifully highlights and correlates the cytologic and histologic features of pleomorphic carcinoma of lung, emphasizing the crucial role that FNA plays in providing adequate assessment of unusual cases. E-PS-04-004 Pulmonary adenocarcinoma with enteric differentiation: a diagnostic pitfall K. Kuan 1 , S. El Hussein 2 , S. Khader 2 1 Montefiore Medical Center/Albert Einstein College of Medicine, Department of Pathology, USA, 2 Montefiore Medical Center/Albert Einstein College of Medicine, USA Background & Objectives: Lung cancer is the second most common malignancies in the United States. Much work has been put into classifying and characterizing various types of pulmonary malignancies in order to optimise treatment plans. Recently, an uncommon variant of lung cancer that resembles colorectal adenocarcinoma is recognized by different scholar bodies and the term pulmonary adenocarcinoma with enteric differentiation (PAED) is coined to this subtype. Here, we present a case report of PAED that is diagnosed with fine needle aspiration (FNA). Methods: An 85-year-old male with a remote history of prostate adenocarcinoma presented to the emergency department complaining of persistent abdominal pain. Except for an increase in CEA level, laboratory work-up was otherwise unremarkable. Imaging studies revealed multiple pulmonary nodules, with a predominant mass measuring 5.7 cm. Hence, biopsies were performed on the largest mass via CT-guided fine needle aspiration (FNA) and core needle biopsy. Diagnosis was made based on the cytomorphology and immunochemical (IHC) stains were used for confirmation. Results: The cells collected from FNA demonstrated gland-forming, columnar carcinoma cells, with vacuolated cytoplasm and basally oriented nuclei. The core needle biopsy finding was in congruence with the FNA biopsy, revealing an adenocarcinoma arising from the alveolar lining, with bland enteric-like columnar cells. Furthermore, IHC stains of the cell block were positive stain for CK7, TTF-1, and CEA-M. As such, these findings along with the IHC results were consistent with a primary lung adenocarcinoma with enteric differentiation. Conclusion: Pulmonary adenocarcinoma with intestinal features is a newly recognized, uncommon entity that we have limited understanding of its pathogenesis. As this case illustrates, the cytomorphology of PAED can be very misleading. The use of IHC stains and the clinical correlation is crucial for making this diagnosis in order to avoid diagnosing this as metastatic disease of colorectal adenocarcinoma. E-PS-04-006 Primary synchronous bilateral breast carcinomas: correlation between cytopathologic and radiologic findings V. Skuletic 1 , S. Cerovic 2 , B. Kovacevic 2 , D. Mikic 1 , J. Dzambas 1 , N. Stepic 2 , M. Elez 2 , I. Zenilo 2 , M. Zaric 2 1 Military Medical Academy, Serbia, 2 Military Medical Academy, Belgrade, Serbia Background & Objectives: Synchronous bilateral breast cancers (SBC) are rare entities with incidence of 2-5% of all breast malignancies. Physicians consider a synchronous contralateral cancer which are diagnosed within 1 month to 1 year of each other. The second tumour is generally considered to be an independent lesion (rather than metastasis) if it contains an in situ component, has a different histology from the first tumour, or possesses a different degree of differentiation from the first tumour. Methods: A 46 year old female presented with 8 cm firm mass in upper outer and inner quadrant of right breast and 1,5 cm tumour felt in the left breast, on the border of upper outer and lower outer quadrant. Mammography and corresponding ultrasound of the right breast revealed malignant-appearing with a contralateral benign-appearing suspect on fibroadenoma. Results: Ultrasound-guided core needle biopsy with imprint cytology of the right breast showed ductal carcinoma while FNA of the left breast lump suggested mucinous carcinoma which was confirmed on histopathology after later core needle biopsy. The pathological examination revealed positivity of both tumours using immunostaining: estrogen and progesterone receptors, HER2 and E-cadherine. Conclusion: We report a rare case of contralateral infiltrating ductal carcinoma and mucinous carcinoma diagnosed during the initial presentation. This highlights importance of fast and minimal invasive cytologic examination in detecting potential pitfall in the diagnostic imaging of the setting of benign-appearing lesions, especially if there is more lesion. It is also possible to differentiate histological types of breast carcinoma and instruct that these are different primary ones and not metastatic tumours, as well as to confirm these are synchronous tumours. Meticulous histology diagnosis and appropriate management helped to improve the longevity with an improved quality of life. E-PS-04-007 Neoplastic pleural effusion involvement and ggynaecological tumour: a rare association J. Fraga 1 , F. Ramalhosa 1 , C. Faria 1 , B. Pimentão 1 , A. Lai 1 , H. Moreira 1 , V. Almeida 1 , R. Almeida 1 , C. Oliveira 1 , G. Fernandes 1 1 Centro Hospitalar e Universitário de Coimbra, Portugal Background & Objectives: The thorax is a frequent site of metastasis from non-pulmonary cancers. Intrathoracic metastatic disease may manifest in many forms. There are a limited number of studies giving the incidence of pleural metastasis from female genital tract tumours. Methods: We present a 62 year old woman with progressive worsening of general condition, with clinical information of two pulmonary nodules in right lung and pleural effusion. Posterior dissection of previous clinical history revealed a diagnostic of an endometrial adenocarcinoma four years ago. Results: Inclusion in paraffin of the sediment obtained after centrifugation of pleural effusion, resulted fibrin imprisoning irregular glandular structures constituted by cells with accentuated nuclear pleomorphism, hyperchromasia and high nuclear/cytoplasm ratio. This cells had cytoplasmic membrane immunoexpression for BerEp4, cytoplasmic positivity for Ck7 and vimentin and nuclear positivity for p53, Pax8 and p16 and negativity for GATA3 and TTF1. Conclusion: Due to the ambiguous clinical history, our study was conditioned by the multiple possible origins of the neoplastic cells. Cytological diagnosis was a pleural involvement by of high grade serous adenocarcinoma of endometrium. Only 2%–4% of tumours of the female genital are disseminated at the time of presentation, usually, spreading to pelvic and para-aortic nodes by the lymphatic system or to distant organs by the hematogeneous system. Thoracic metastases from ggynaecologic malignancies exhibit various imaging patterns. Metastases from endometrial cancer typically manifest as pulmonary nodules and lymphadenopathy, whereas ovarian cancer often manifests with small pleural effusions and subtle pleural nodules. E-PS-04-008 Significance of nuclear morphometry in fine needle aspiration from benign tumours and invasive carcinomas of breast H. Sheikh Alard 1 1 Damascus University, France Background & Objectives: Fine-needle aspiration of breast masses is a safe and cost-effective technique for the diagnosis but this diagnosis is still aubjective. The nuclear morphometry can reduce this subjectivity when it is applied on the aspiration of breast masses. Objectives: measuring the nuclear area and perimeter then - comparing these values between the benign masses and invasive carcinomas. - studying if there is a relation between those values and a) carcinoma's grade evaluated on aspirations, b) carcinoma's grade evaluated on histolofical sections, c)status of lymph nodes in the same side, d)size of mass, and e)degree of cohesion of carcinoma's cells. - evaluating the average of variations in the values of nuclear area and perimeter between the group of benign masses and invasive carcinomas. Methods: 101 masses sent to the department of surgical pathology in the two hospitals of damasuc university for frozen sections, between 2015-2017. The aspiration had been performed on these masses (G210). The smears have been fixed with ethanol 90% and stained with hematoxyline eosin. The slids of aspirations and the slids of histological sections have been scanned by NIKON (HDCE-10C). The nuclear area and nuclear perimeter have been measured by an open source image processing program (Image J). The nuclear grade of invasive carcinoma has been evaluated by using the Robinson's system. The histological grade of invasive carcinomas has been evaluated by using the Nottingham modification of Bloom-Richardson system. Abbraviations: Nuclear area NA, Nuclear perimeter NP. Results: - There is a statistical significance for the difference between: a) NA, NP and the average of variations of these values of isolated cells in benign masses and those in invasive carcinomas. b) NA and NP of cohesive cells in clusters and this of isolated cells in the group of invasive carcinomas. c) NA of cohesive cells in clusters and the nuclear area of isolated cells in the group of invasive carcinomas. d) NA and NP of the group of invasive carcinoma with nuclear grade 1 and those with nuclear grade 2 and 3. e) NA and NP of cohesive cells and this of isolated cells in the group of invasive carcinoma with N+. f) NA and NP of cohesive cells and isolated cells and also mean nuclear morphometry in the group of invasive carcinoma with histological grade 2 and those in the group of invasive carcinoma with histological grade 3 (the specimen of invasive carcinoma grade 1 is not sufficient for statistical study) - No statistical significance for the difference between: a) NA and NP of cohesive cells and mean nuclear morphometry in benign masses and those in invasive carcinomas. b)the average of variations in the values of NA of cohesive cells in benign masses and those in carcinomas. c) NA and NP of cohesive cells in clusters and this of isolated cells in the group of benign tumours. d) NA and NP in the 4 groups of lymph nodes status of invasive carcinomas e) NA and NP of the group of invasive carcinoma with N+ and this of N-. f) NA and NP of cohesive cells and this of isolated cells in the group of invasive carcinoma with N-. g) NA and NP of the 4 groups of invasive carcinoma's size. h) NA and NP in the three degrees of cohesiveness of carcinomatous cells. - NA: benign tumours (64.14 +/-18.68)um 2 , invasive carcinomas (109.69+/-39.53)um 2 . - NP: benign tumours (28.41+/-6.67)um 2 , invasive carcinomas (43.87 +/-3.89)um. Conclusion: -The NA and NP play an important role in distinguishing the benign tumours from invasive carcinomas, specially isolated cells (values of isolated cells in invasive carcinomas are bigger than those of isolated cells in benign tumours). -The difference between the NA and NP of cohesive cells in clusters and those of isolated cells is bigger in the group of invasive carcinomas than in the group of benign tumours with statistical significance. -the average of variations in NA and in NP in the group of invasive carcinomas are more important than the average of variations of these values in the group of benign tumours. -The values of NA, NP and mean values in the group of invasive carcinoma with histological grade 3 are bigger than those in the goup with histological grade 2. -The variations in the values of NA and N are more important in the group of invasive carcinomas grade 3 than in the group of invasive carcinomas grade 2. -The NA in the group of invasive carcinomas with nuclear grade 3 evaluated on FNA are bigger than those of invasive carcinomas with nuclear grade 2and 1. -The difference between NA and NP of cohesive cellls in clusters and those of isolated cells has a prognostic value for the metastases in lymph nodes but the nuclear morphometry itself doesn't have a prognostic significance for the metastases in lymph nodes. -No relation between nuclear morphometry (NA and NP) and the size of invasive carcinomas. E-PS-04-009 Cytological and histological aspects of tall cell and hobnail variant of papillary thyroid carcinoma: 3 cases U. Aykutlu 1 , C. Uzun 1 , M. Ozsen 1 , Y. Cakir 1 1 Erzurum Regional Training and Research Hospital, Turkey Background & Objectives: Papillary thyroid carcinoma (PTC) is the most common tumour among the thyroid malignancies. This presentation aim to present the clinicopathological features of tall cell and hobnail variant of PTC cases. Methods: We report three cases diagnosis with tall cell and hobnail variant of PTC by fine needle aspiration and total thyroidectomy procedure. Results: One of the 2 cases diagnosed with Tall cell variant of PTC is 65 years old male. The other case is 48 years old, female. Microscopic examination of fine needle aspiration (FNA) material show numerous intranuclear inclusions and atypical thyrocytes with long cytoplasm aligned near basal nucleus alignment. Histopathological evaluation revealed a tumoural lesion with the features of distinct restrictive papillary thyroid carcinoma, which consisted of long cylindrical cells, of which heights are at least 2-3 times their width. The case, which is diagnosed as Hobnail variant of PTC, is 51 years old male. Microscopic examination of FNA material showed atypical thyrocytes with papillary thyroid carcinoma characteristics, as well as dyscohesive cells with loss of polarity and isolated cells with eccentric nucleus and teardrop-shaped cytoplasm. Histopathological evaluation revealed a tumoural lesion composed of complex papillary and micropapillary structures with nuclear cells that have features of papillary thyroid carcinoma. Apical localised nuclei of the tumour cells show typical hobnail pattern. Conclusion: Most of the PTC variants have good prognosis, however tall cell variant, hobnail variant, columnar cell variant are associated with poor prognosis. It is important to distinguish these variants from the classical variant for better patient management. E-PS-04-010 Parotid gland metastasis from endometrial cancer: first reported case with cytologic description S. Lajara 1 , R. Balakrishnan 1 , C. Castrodad 1 , A. Colanta 1 , S. Khader 1 1 Montefiore Medical Center/Albert Einstein College of Medicine, USA Background & Objectives: Endometrial adenocarcinomas are the most common ggynaecologic malignancies in the USA. Type 1 is associated with low stage at diagnosis and better prognosis, while type 2 is associated with increased intraperitoneal and metastatic spread. Typical metastatic sites include regional lymph nodes and lungs; uncommon sites are the liver, adrenals, soft tissue, bone and brain. Our aim is to describe an unusually widely metastatic well-differentiated endometrial adenocarcinoma and the cytologic findings of a fine needle aspiration (FNA) of the parotid gland, a rare site of metastasis. Methods: We report a case of a 65-year-old female with a past medical history of well-differentiated, FIGO stage IB endometrioid endometrial adenocarcinoma, presenting with a necrotic intraparotid lymph node. Two years prior to presentation, she was diagnosed with multiple brain lesions, managed as cancer of unknown primary site. Her endometrial cancer was considered as an unlikely primary because the brain is an uncommon metastatic site. However, pathology revealed metastatic endometrial adenocarcinoma. A gingival nodule, identified during dental extraction, also revealed metastatic adenocarcinoma. Results: FNA of her left parotid gland revealed scattered clusters of large pleomorphic cells with prominent nucleoli and moderate to abundant pale, sometime clear cytoplasm compatible with metastatic endometrial adenocarcinoma. Conclusion: An aggressive clinical course with extensive distant metastasis is peculiar for low-stage, well-differentiated endometrial adenocarcinomas. Brain involvement is extremely uncommon, and is usually seen in high grade and high stage tumours. Gingival metastasis is also vanishingly rare. To our knowledge, there is no reported case of endometrial carcinoma involving the parotid gland in literature. E-PS-04-012 Cytologic features of gastric type mucinous carcinoma of the uterine cervix K. Suh 1 , K. Kim 1 1 Chungnam National University Hospital, Republic of Korea Background & Objectives: Gastric type mucinous carcinoma (GMC) of the uterine cervix is difficult to recognize in cytologic specimens. These tumours are characterised by bland nuclear features and abundant mucin or goblet cell differentiation, but clinically aggressive. GMC is not associated with human papillomavirus (HPV) infection. We analysed cytologic features of GMC of the uterine cervix compared to usual type endocervical adenocarcinoma. Methods: We reviewed the cervical and ascites fluid smears from 3 patients with a pathologic diagnosis of GMC. All slides were conventionally smeared or liquid-based prepared (ThinPrep) and stained with papanicoloau stain. Results: Among three cases, the cytologic diagnoses were atypical glandular cells, favor neoplastic in two cases and adenocarcinoma in one case. High risk-HPV testing in these 3 cases was negative. Histologically, the tumours consist of irregular angulated glands invading the cervical stroma. These cells were positive for MUC6 and p53, but negative for p16. Cytologically, the tumour cells had bland nuclear morphology with low nuclear to cytoplasmic ratios and abundant mucinous cytoplasm. The characteristic features of GMC were honeycomb sheets, vacuolar or foamy cytoplasm with yellowish brown hue due to mucin, intracytoplasmic neutrophil entrapment, and occasional small nucleoli, compared to usual type endocervical adenocarcinoma. Conclusion: Even though the case numbers are small, GMC may be recognized by cytologic features, such as honeycomb sheets of bland tumour cells with abundant foamy cytoplasm with yellowish brown hue due to mucin. E-PS-04-013 Colonic adenocarcinoma presenting with supraclavicular lymph node metastasis: a rare case report H. Seneldir 1 , G. Kir 1 , B. Gucluer 1 , N. Ozbay 1 , A. Gapbarov 2 , O. Alimoglu 2 1 Istanbul Medeniyet University, Department of Pathology, Turkey, 2 Istanbul Medeniyet University, Department of General Surgery, Turkey Background & Objectives: In colorectal cancers, the most common sites of metastasis are liver, lung and peritoneum. Non-regional lymphatic involvement in colon primary is an uncommon finding. Methods: A 69-year-old female patient was admitted to our hospital with a progressively enlarging swelling of the left supraclavicular region for approximately 4 weeks. Ultrasonography of the neck revealed multiple nodules, with rounded and heterogenic echo parenchyma which suggested metastasis. An ultrasound-guided fine needle aspiration biopsy was performed from the largest mass of the left supraclavicular region. Cytology revealed carcinoma metastasis. Immunohistochemical examination showed the tumour cells at the cell block to be positive for CK20 and CDx2 and negative for CK7 and p40 expression. The positron emission tomography (PET) of the patient, which was investigated for etiology and origin, was observed hypermetabolic area that about 6x3 cm at the transverse colon. Upon this the patient was performed right hemicolectomy and excisional biopsy of left supraclavicular lymph node. Results: Macroscopic examination of the right hemicolectomy showed a infiltrating mass measuring 4x4 cm on the transvers colon and the tumour extended into the pericolic fat. Histologically the appearance was moderately differentiated colonic adenocarcinoma. Histopathologic examination of the left supraclavicular lymph node again confirmed as metastasis from colonic adenocarcinoma. Conclusion: Supraclavicular lymph node metastases are common occurrence in breast cancer, lung cancer, gastro-oesophageal cancer and lymphoma. Colonic cancer represents an unusual primary for supraclavicular lymph node metastases. E-PS-04-014 Rosai-Dorfman disease: cases report Y. Gulyaeva 1 , T.I. Nabebina 1 , A.T. Dubrovskij 1 1 National Cancer Centre, Belarus Background & Objectives: Rosai–Dorfman disease is a reactive histiocytic proliferation of unknown etiology characterised by a proliferation of histiocytes with distinctive cytologic and immunophenotypic features. Methods: We describe here two: one - with damage to the soft tissues and bones of the face and lymph nodes, the second - with damage to the CNS and lymph nodes. Results: Histologically, lymph nodes are significantly enlarged. At low-power magnification, the overall nodal architecture is generally maintained, and sinuses are distended by a proliferation of large histiocytes associated with small lymphocytes and plasma cells. The lymph node parenchyma is characterised by follicular hyperplasia and plasmacytosis in interfollicular areas. Mitotic figures are rarely identified. the histiocytes are large and characterised by abundant eosinophilic cytoplasm, distinct cell borders, and a central round nucleus with a prominent nucleolus. These histiocytes also exhibit emperipolesis. At extranodal sites there are large histiocytes and emperipolesis, the lesions are accompanied by fibrosis. Tumour cells demonstrated the following immunoprofile: S-100+, CD68+, CD1a-. The patients with damage to the CNS received surgical treatment, both patients are under observation for six months after diagnosis. Conclusion: The Rosai–Dorfman disease prognosis is excellent, with most patients being free of disease or with stable disease. However, some patients may develop recur-rent disease in the original site or other body sites. E-PS-04-015 Pitfall in urinarycytology - are non-neoplastic findings not relevant at all? - crystals versus parasites A.M.G. Pereira 1 , C. Padrao 1 , F. Galante Pereira 1 , R. S. S. Oliveira 1 , A.T. Alves 2 1 Hospital Prof. Doutor Fernando Fonseca, EPE, Portugal, 2 Instituto de Anatomia Patológica da Faculdade Medicina Universidade de Lisboa, Portugal Background & Objectives: In an era so focused on cancer, sometimes we tend to disregard non-neoplastic findings that are important to diagnosis, treatment and clinical outcome of the patients. With these cases we pretend to raise awareness for non-neoplastic findings in urine cytology specimens namely the differential diagnosis between uric acid crystals and parasites. Methods: We report two cases of urinary cytology specimen’s analysis. One, referring to 77-years-old male patient in the context of follow up of high grade urothelial cancer, and the other, referring to 86-years-old-female patient, on etiological investigation of a non-lithiasic hydronephrosis. Results: Both cytologies had similar findings. On microscopic examination, we identified some elliptical structures that seemed to be parasitic in nature. The objects were considerable smaller than eggs of Schistosoma haematobium, lacked a single terminal spine and had no miracidium which raised suspicion of a different structure. These objects appeared to have a spine on both ends and were highly birefringent under polarized light, making it possible to identify them as uric acid crystals. Conclusion: Crystals in urine cytology can present in various shapes and sizes and uric acid crystals are one of the most variable, sometimes with pointy extremities and multiple colors that be confused with parasite eggs, exogenous material or artifacts. It is especially important to avoid pitfalls and clarify the diagnosis of Schistosoma’s eggs because of its relation with squamous cell carcinoma of the bladder. E-PS-04-016 Collecting duct carcinoma of the kidney diagnosed on fine needle aspiration with distinctive cytomorphology: a case report with histological correlation and literature review D. Pinto 1 , X. Qian 2,3 1 Centro Hospitalar de Lisboa Ocidental, EPE, Portugal, 2 Brigham and Women's Hospital, USA, 3 Harvard Medical School, USA Background & Objectives: Collecting duct carcinoma (CDC) of the kidney is a rare high-grade adenocarcinoma of the renal medullary region. Its diagnosis is based on criteria proposed in the WHO 2016. Cytologic features, however, are considered mostly non-specific. We report on a case of CDC diagnosed by fine needle aspiration (FNA) cytology and perform a literature review. Methods: A relevant case was selected from our routine. Literature review was performed. Results: 58-year-old man with history of collecting duct carcinoma of the kidney and follicular thyroid carcinoma. A mass of the left humerus was detected and submitted to FNA. Smears were moderately cellular and contained epithelial cells forming acinar clusters. Fragments of a paucicellular fibroconjuctive tissue were identified. Cytology was high-grade. Tumour cells were positive for CK7, CKAE1/AE3, FH, PAX8 and SMARCB1 and negative for AMACR, AR, CK20, ERG, OCT3/4 and TTF1. A diagnosis of metastatic CDC was made. Conclusion: The observed fibroconjunctive fragments are compatible with a desmoplastic stroma. Previous publications have shown these are part of the morphologic spectrum of CDC on FNA cytology, but not specific. To make a specific diagnosis, we followed an algorithmic immunohistochemistry approach, excluding different primary locations, namely urothelial carcinoma, and other distal nephron tumours showing a high-grade adenocarcinoma morphology with a desmoplastic stroma. Diagnosing a specific entity is important not only to enable future studies of tumour genetics and pathogenesis, but also to allow for appropriate therapy. This is possible on FNA cytology. Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-05 | Dermatopathology Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-05 | Dermatopathology E-PS-05-001 Hepatitis C-related liver cirrhosis associated with mixed cryoglobulinemia M. Rolon 1 , M. Tapias 2 , L. Barrera 3 , J. Alvarez-Figueroa 3 1 Department of Pathology and Laboratories, Hospital Universitario Fundación Santa Fe de Bogotá. Bogotá, Colombia, 2 Transplant and Hepatobiliary Surgery Service, Hospital Universitario Fundación Santa Fe de Bogotá. Bogotá, Colombia, 3 Department of Pathology and Laboratory Medicine, Hospital Universitario Fundación Santa Fe de Bogotá. Bogotá, Colombia Background & Objectives: Cryoglobulinemia is a disease defined by the presence of abnormal proteins in blood that accumulate and become insoluble at low temperatures. Clinically, it is a multisystemic entity with cutaneous involvement due to purpuric lesions. It is classified as type I (monoclonal) with the presence of intravascular deposits of cryoglobulin and type II (mixed) with acute vasculitis. We present a patient with a mixed cryoglobulinemia associated with hepatitis C virus infection. Methods: A 56-year-old male with a diagnosis of decompensated cirrhosis due to chronic Hepatitis C infection, hepatic encephalopathy, portal hypertension, refractory ascites and renal dysfunction. During his hospitalization presented hemorrhagic purpuric and painful lesions compromising the lower limbs associated with decreased distal perfusion and blister on the right leg. Results: The skin biopsy revealed areas of necrotic epithelium, superficial perivascular mononuclear inflammatory infiltrate associated with abundant extravasated erythrocytes, karyorrhexis around small vessels in the upper and middle dermis with fibrinoid necrosis of vascular walls, abundant interstitial hemorrhage, deposits of hyaline material inside the vascular structures or fibrin thrombi. Such findings where compatible with necrotizing hemorrhagic leukocytoclastic vasculitis due to mixed cryoglobulinemia. Patient received pulses of methylprednisolone, plasmapheresis improved of skin lesions; however, with posterior anuria, and despite hemodialysis he died. Conclusion: In the presence of an acute vasculitis, although there is no presence of hyaline thrombi, it is important to raise the suspicion of mixed cryoglobulinemia. We presented a case of Hepatitis C virus-related mixed cryoglobulinemia. E-PS-05-002 Cutaneous adenoid cystic carcinoma metastasizing to the lung 10 years after the initial diagnosis S. Sotiriou 1 , M. Bobos 2 , D. Hatzibougias 2 , E. Michalopoulou-Manoloutsiou 2 , E. Athanasiou 2 , E. Goupou 2 , I. Boukovinas 3 , S. Galanis 4 , I. Kostopoulos 1 , T. Koletsa 5 1 Pathology Department, Faculty of Medicine, Aristotle University of Thessaloniki, Greece, 2 "Microdiagnostics" Ltd., Thessaloniki, Greece, 3 Bioclinic Thessaloniki, Greece, 4 "G. Papanikolaou" General Hospital, Thessaloniki, Greece, 5 Pathology Department, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece Background & Objectives: Cutaneous adenoid cystic carcinomas (CACCs) are rare neoplasms, that most commonly arise in the scalp and metastasize to the lungs, even many years after the initial diagnosis. The aim of this case report is to raise awareness regarding this entity and to point the importance of the differential diagnosis, especially in the context of metastatic disease. Methods: In 2008 a 66-year-old man has undergone resection of a skin nodule of the scalp, and ten years later (2018) has undergone a biopsy of a pulmonary lesion. Results: Microscopically, the cutaneous lesion represented an infiltrating carcinoma. The neoplastic cells were immunoreactive for AE1/AE3 and CD117, and arranged in tubular and cribriform formations, with an inner luminal (highlighted with EMA) and an outer basal/myoepithelial cell layer (highlighted with SMA). Perineural infiltration was prominent. The pulmonary lesion represented a carcinoma with similar morphology. Based on the histological and immunohistochemical findings, but also on the absence of other lesions, our final diagnosis was that of a CACC with pulmonary metastasis. Conclusion: CACC must be differentially diagnosed from metastatic ACC, but also from primary cutaneous neoplasms with similar morphology, such as secretory, cribriform and adenoid basal cell carcinoma. A high level of suspicion is recommended whenever a patient with a history of CACC presents a second lesion. Clinicopathological correlation is of paramount importance in the differential diagnosis between primary and secondary ACCs. E-PS-05-003 Eccrine angiomatous hamartoma - a seemingly benign lesion with an unpredictable behaviour A.C. Lisievici 1 , T.A. Georgescu 2 , A. Zota 3 , T. Tebeica 4 1 Carol Davila University of Medicine and Pharmacy, Bucharest, Romania, 2 Department of Pathology, Bucharest Emergency University Hospital, Romania, 3 Department of Dermatovenerology, Dr. Leventer Centre, Bucharest, Romania, 4 Department of Pathology, Dr. Leventer Centre, Bucharest, Romania Background & Objectives: Eccrine angiomatous hamartoma (EAH) represents a rare nevocytic malformation composed of sweat gland and mesenchymal elements including blood vessels and smooth muscle, which usually occurs in children. Most cases of EAH reported in the literature had an indolent behavior and did not recur, except for 2 cases from a retrospective study. Another case report presented a patient with localized severe pain, which warranted partial amputation of the affected finger. Methods: We report the case of a 22–year-old male who presented a few years ago in another center with a red plaque on his inner thigh, that incresed in size and became tender in the past few months. The lesion was surgically excised and diagnosed as cavernous hemangioma. Two years later, the lesion recurred and the initial histopathological specimen was referred to our clinic for second opinion. Results: Histopathological examination revealed a proliferation of blood vessels in close relation with the epidermis, focally mimicking angiokeratoma. However, a significant number of sweat glands and smooth muscle fibers were intermingled between the vascular structures. The lesion was diffusely infiltrating both reticular dermis and hypodermis and was covered by hyperplastic epidermis with verrucous features. Lateral excision was incomplete. Conclusion: EAH is a rare lesion with unusual behavior, which can be easily misdiagnosed due to the bland appearance of its components. Simple excision is usually curative, but recurrences, although rarely reported in the literature, are possible and warrant increased awareness for practicing pathologists and clinicians. Therefore, in such lesions, close follow up is recommended. E-PS-05-004 Dedifferentiated melanoma with rhabdomyosarcomatous transdifferentiation - a rare case report J. Soukup 1,2 , M. Manethova 1,2 , L. Krbal 1,2 1 The Fingerland Department of Pathology, University Hospital Hradec Kralove, Czech Republic, 2 Charles University Faculty of Medicine in Hradec Kralove, Czech Republic Background & Objectives: Dedifferentiation in melanoma is an unusual phenomenon, characterised by loss of normal immunohistochemical profile and morphology. Some of these tumours may show a divergent differentiation including rhabdomyosarcomatous. Such cases are exceedingly rare, with less than 12 cases reported. Here we present an additional case. Methods: 84-year-old male presented with a skin tumour of a right arm. Excision measuring 55 x 35 x 12 mm with the tumour measuring 35 x 35 x 8 mm was retrieved. Histopathologic evaluation and immunohistochemical staining for SOX10, S100, HMB45, MelanA, CD30, CD45, CD56, CD117, CK AE1/3, CK18, CK20, BER-EP4, p63, SMA, INI1, synaptophysin, ERG, desmin, myoD1, myogenin and BRAF V600E was performed. Results: The tumour was situated in superficial dermis and composed of solid sheets of atypical rhabdoid cells with vesicular nuclei and nucleoli. Mitoses were conspicuous. Tumour cells expressed INI1 and desmin in diffuse and strong fashion with focal expression of myoD1 and myogenin. All other immunohistochemical melanoma markers (SOX10, S100, HMB45, MelanA) were negative. In the surrounding epidermis, remnants of a junctional and lentiginous atypical melanocytic proliferation with pagetoid spread were identified, consistent with melanoma in situ, with maintained SOX10 expression. Conclusion: Melanoma with rhabdomyosarcomatous differentiation is a rare tumour that must be considered in differential diagnosis when dealing with rhabdomyosarcoma of the skin, especially in elderly. European Regional Development Fund-Project BBMRI-CZ: Biobank network – a versatile platform for the research of the etiopathogenesis of diseases, No: EF16 013/0001674. E-PS-05-005 A case of sebaceous carcinoma arising on the wrist - an atypical location for an uncommon neoplasm M. Kilmpasani 1 , I. Karafoulidou 1 , A. Baliaka 1 , N. Pastelli 1 , Z. Tzimorota 2 , S. Papaemmanouil 1 1 Department of Pathology, General Hospital of Thessaloniki "G. Papanikolaou", Greece, 2 Department of Plastic, Reconstructive and Hand Surgery, General Hospital of Thessaloniki "G. Papanikolaou", Greece Background & Objectives: Sebaceous carcinoma is an uncommon cutaneous malignant neoplasm, often misdiagnosed as a benign lesion or a basal cell carcinoma. It is most commonly found on head and neck, mainly at periocular sites. The extremities are an atypical location for an extraocular sebaceous carcinoma. We report the case of a 78-year-old patient with a tumour on the right wrist, reportedly existent for at least 2 years. Methods: Following excision, the protruding tumour measured 2.3cm, and demonstrated a tan-pink cut surface. It was examined in FFPE sections with hematoxylin-eosin and immunohistochemical stains. Results: The neoplasm consisted of cells with multivacuolated, clear cytoplasm and oval nuclei. They formed well-demarcated, solid nests in a desmoplastic, highly vascularized stroma, with the presence of comedo-type necrosis and vascular neoplastic emboli. A high mitotic activity was prominent, including mainly atypical mitoses. The overlying epidermis showed areas of low-grade dysplasia with hyperkeratosis and parakeratosis, while the adjacent epidermis demonstrated independent foci of full-thickness, dysplastic epithelium, with evident parakeratosis. The final diagnosis was sebaceous carcinoma of the skin, grade I, with coexisting, multiple foci of in situ carcinoma in the adjacent skin. Conclusion: An intraepidermal growth pattern is seen more often in periocular sebaceous carcinoma and less commonly at extraocular sites. A grading system based on growth pattern has been proposed; moreover, vascular invasion, persistence of symptoms longer than 6 months and size larger than 10mm, among others, also seem to be related with an adverse prognosis. Given the above, our case demonstrates some interesting features. E-PS-05-007 The curious case of an anal polyp that turned out to be lymphangioma circumscriptum: a case report A.D. Plopeanu 1 , A. Dema 2 , S. Olariu 3 , S. Taban 1,4 1 Emergency Clinical County Hospital "Pius Brinzeu" Timisoara, Romania, 2 Department of Pathology, Emergency Clinical County Hospital "Pius Brinzeu", Timisoara, Romania, 3 Emergency Clinical County Hospital "Pius Brinzeu" Timisoara, "Victor Babes" University of Medicine and Pharmacy Timisoara, Department of Surgery, Romania, 4 ''Victor Babes'' University of Medicine and Pharmacy Timisoara, Department of Pathology, Romania Background & Objectives: Lymphangioma circumscriptum is a rare benign tumour consisting of abnormal ectatic lymph vessels involving the upper part of the dermis. This infrequent lesion appears with predilection on the extremities, trunk and axilla. The best course of treatment is not well established. Although considered the most effective, surgery is associated with a high risk of complications. The aim of this case report is to highlight the possibility of diagnosing an uncommon lesion with a localization rarely mentioned in the specialty literature. Methods: We report the case of a 35 years old woman who was operated on for external hemorrhoids and an anal polyp. The microscopic examination revealed the polyp to be a benign vascular tumour and further immunohistochemistry tests were performed in order to confirm the diagnostic. Results: The histopathological examination revealed an achanthotic and hyperparakeratotic epithelium, with numerous dilated vessels in the papillary dermis, vessels that in hematoxylin-eosin staining appeared to be lymphatic. In order to confirm the diagnosis, further immunohistochemical examination were carried out. The vessels were proven to be lymphatic by being positive for D2-40 and CD31 antibodies, allowing us to give a positive diagnostic for lymphangioma circumscriptum. Conclusion: Lymphangioma circumscriptum is a rare tumour involving the lymphatic vessels in the dermis and despite its infrequent nature, it must be taken into account for differential diagnosis, even when appearing in an unusual topographic area. E-PS-05-008 A 3-year retrospective study demonstrating an important histopathologic clue for diagnosing cutaneous Rosai-Dorfman disease A.C. Lisievici 1 , T.A. Georgescu 2 , A. Rizoiu 3 , A.M. Stanciu 4 , T. Tebeica 5 1 Carol Davila University of Medicine and Pharmacy, Bucharest, Romania, 2 Department of Pathology, Bucharest Emergency University Hospital, Romania, 3 Department of Dermatovenerology, MEDINVEST, Bucharest, Romania, 4 Department of Dermatovenerology, Dr. Leventer Centre, Bucharest, Romania, 5 Department of Pathology, Dr. Leventer Centre, Bucharest, Romania Background & Objectives: Cutaneous Rosai-Dorfman disease is a rare non-lymphoid cutaneous infiltrate of unknown etiology. It is currently acknowledged that skin lesions may represent the sole manifestation of Rosai-Dorfman disease, although involvement of both skin and lymph nodes is much more frequently encountered. Histologically, it is characterised by an abundant inflammatory infiltrate, in which numerous histiocytes are identified, some of them showing classic emperipolesis. Immunohistochemically, the large histiocytes express both S100 and CD68, but are negative for CD1a. Methods: This is a retrospective study including all cutaneous Rosai-Dorfman diseases that were diagnosed in our Dermatopathology unit during a period of three years (2016-2018). Clinical information was retrieved from the virtual database. We thoroughly re-examined all Hematoxylin-Eosin and immunohistochemically stained slides, aiming to establish clinico-pathological correlations. Ancillary studies included: S100, CD68, CD1a, CD79a, CD30. Results: Clinically, the face and the trunk were involved equally often, while the extremities and the buttocks were less affected. 50% of all cases presented as nodules, 25% presented as indurated plaques with subcutaneous nodules and 25% cases mimicked a panniculitis. 62.5% of all patients had solitary lesions, while 37.5% presented with multiple nodules. Histologically, all cases presented an inflammatory reaction in which plasmocytes abounded and bordered the infiltrate. This feature was more than once, the first clue to this diagnosis. Conclusion: In our opinion, an abundant plasma cell infiltrate that surrounds a diffuse lympho-histiocytic infiltrate is highly suggestive for this entity and an important clue that should warrant a thorough analysis of the slide, in order to find characteristic emperipolesis. This sign can be especially useful when dealing with atypical lesions, like those limited to the hypodermis and mimicking a panniculitis. E-PS-05-009 ALK-positive atypical spitz tumour: report of two cases and brief review of the literature C. Ricci 1 , A. De Leo 2 , G. Santandrea 3 , B. Corti 2 1 Department of Biomedical and Neuromotor Sciences, Bellaria Hospital, Bologna, Italy, 2 University of Bologna, Department of Surgical pathology, Italy, 3 Pathology Unit, S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy Background & Objectives: Spitz tumours (STs) are a subgroup of melanocytic neoplasms ranging from Spitz nevus (SN) to atypical Spitz tumours (ASTs) and spitzoid melanoma (SM), the latter with capacity of metastasis and lethal outcome. In the last years molecular investigations played a central role in the sub-characterization of STs. In particular, ALK fusion has been noticed in 10% of STs, including 5% of ASTs and 1% of SMs. Herein, we report two cases of ALK-positive ASTs (ALK-ASTs) arose during adolescence. Methods: The first patient was a 16-year-old boy with a lesion on the right leg; the second one was a 14-year-old boy with a lesion on the right foot over the previous months. Immunoistochemistry (IHC) for HMB45, MART1, S-100, Ki67, ALK, p16 and BAP1 was performed. Results: In both cases, histology revealed a wedge-shaped proliferation of atypical spindle, epithelioid and multinucleated melanocytes, arranged in a plexiform pattern in deep dermis. Mitoses were present ( ≤ 4/mm 2 ), even deep/marginal. Tumour cells were strongly positive for S-100, p16 and ALK1; Ki-67 was low and BAP-1 maintained. A diagnosis of ALK-AST was rendered. Both patients underwent a sentinel lymph-node biopsy and, in the first patient, we found subcapsular ALK-positive tumour clusters. In both cases, no recurrence or disease progression were detected. Conclusion: Our report confirms that ALK expression identifies a biologically and morphologically distinct subcategory of ASTs, unrelated to the other variants. Further investigations are needed to clarify the prognostic meaning of these findings. E-PS-05-010 The role of the pathologist in the Mohs micrographic surgery: a retrospective study I. Español 1 , I. Trias 1 , M. Alegre 2 1 Hospital Plató. Pathology DP, Spain, 2 Hospital Plató. Dermatology, Spain Background & Objectives: Transplant glomerulitis is a key feature of antibody-mediated rejection. Leukocytes occluding the glomerular capillaries define its morphological pattern. It is difficult to recognize and its scoring only has a fair interobserver agreement. We aimed to determine and validate a well reproducible immunohistochemical marker for glomerulitis, and looked at its prognostic value. Methods: Receiver operator curves (ROC) using CD3, CD45, or CD68 positive cell counts in the glomeruli of kidney transplant biopsies with glomerulitis or without relevant pathology were used to determine cut-offs. Findings were independently validated, tested for interobserver agreement, and compared to other rejection patterns. The prognostic value was investigated in a cohort of patients (n=95) transplanted in the presence of donor-specific antibodies (DSA). Results: A cut-off >5.5 CD68 positive cells in the most affected glomerulus (CD68 max ) resulted in an area under the curve (AUC) of 0.966. CD68 max correlated with the percentage of glomeruli with CD68 counts above the cut-off (ρ = 0.875). Three risk groups (baseline, low, high) with prognostic impact on graft survival were established using ROC comparing cases with glomerular Banff scores 0 vs. 1 (AUC = 0.891, cut-off > 3.9 % of glomeruli) and 1 vs. 2-3 (AUC = 0.867, cut-off >64.4 %). Interobserver agreement was good and independent of the level of expertise. In the DSA positive cohort, the risk groups proved to be an early and independent prognostic marker of poor graft function. Conclusion: Addition of a CD68 stain to the routine analysis of kidney transplant biopsies provides additional diagnostic and prognostic information. E-PS-05-011 Cutaneous microcystic/reticular schwannoma determined incidentally in pilonidal sinus specimen: a case report R. Bedir 1 , S. Orhan 2 , F.G. Gülname 2 1 Recep Tayyip Erdogan University Deparment of Pathology, Turkey, 2 Department of Pathology, Recep Tayyip Erdogan University, Medical Faculty, Turkey Background & Objectives: Schwannoma is a common, slow-growing, encapsulated and usually asymptomatic benign peripheral nerve sheath tumour. Microcystic/reticular schwannoma (MRS) is a very rare histological variant of schwannoma. MRS is a recent addition to this group of tumours, which have a predisposition for visceral organs. Unlike typical morphology of schwannomas, it shows no Antoni A, Antoni B areas or Verocay bodies. Here, we present the case of a 28-year-old male who has an incidentally detected cutaneous MRS in pilonidal sinus specimen. Methods: The specimen was fixated with 10% buffered formalin and were processed by conventional histopathological methods using paraffin embedding, sectioning and Hematoxylin-Eosin staining. Results: A 28-year-old male patient presented with anintermittent painful swelling in the anogenital region. The clinical impression was a pilonidal sinus and it is surgically removed. Macroscopic examination revealed a sinus tract and nearby mass under the skin with a gray-white solid cut surface showing focal myxoid appearance which is found incidentally. Mass measured 2x1.5 cm, and it was well circumscribed with lobular appearance. Microscopic examination revealed spindle-shaped neoplastic cells which have scant eosinophilic cytoplasm and bland hyperchromatic round to oval nuclei. There is no mitotic figures, cytological atypia or necrosis. The tumour cells were forming lace-like, retiform or pseudoglandular structures containing abundant basophilic myxoid material. The tumour showed strongly diffuse positivity for S-100 protein, vimentin, and GFAP while negative for CD34, pan-CK (AE1/AE3), HMB-45 and EMA in immunohistochemical staining. Finally the case was diagnosed as cutaneous MRS. Conclusion: Schwannomas are benign tumours which arise from the cells of Schwann that form the neural sheath. There are several morphologic variants of schwannoma, including cellular schwannoma, ancient schwannoma, plexiform schwannoma, epithelioid schwannoma, glandular schwannoma, melanotic schwannoma, hybrid schwannoma/perineurioma and microcystic/reticular schwannoma. MRS is a very rare variant of schwannomas with benign biological behaviour. Both surgeons and pathologists should consider MRS in the differential diagnosis of soft tissue tumours with a reticular growth pattern. E-PS-05-012 Primary cutaneous myxoid spindle cell squamous cell carcinoma of the scalp: a case report M. Suntur 1 , O. Semerci 1 , R. Bedir 1 1 Recep Tayyip Erdogan University, Department of Pathology, Turkey, Background & Objectives: The primary cutaneous squamous cell carcinoma (SCC) is the second most common skin cancer. Primary cutaneous myxoid spindle cell squamous cell carcinoma (MSC SCC) is an extremely rare variant of SCC with only 7 cases reported in the literature. Here, we present an MSC SCC case located at the scalp of a 78-year-old male patient and its differential diagnosis with immunohistochemical results. Methods: A 78-year-old male patient presented to the clinic with the ulcerated nodular lesion at the parietal region of the scalp. The lesion was totally excised. In microscopic findings, we identified a tumour which showing infiltration as single cells and cell groups in the myxoid stroma of dermis and also causes ulceration in the epidermis. The depth of invasion of thetumour was 0.3 cm and the diameter of the tumour was 0.7 cm (stage pT1). In immunohistochemistry tumour cells showed positivity for pan-cytokeratin (AE1/AE3), p40, vimentin and negativity for S-100, HMB-45, MART1, SMA, desmin. Results: The diagnostic criteria of MSC SCC in the literature are the significant myxoid stromal changes, observing these changes onmore than half of the lesion, positive staining of neoplastic spindle (and squamous) cells with minimum one cytokeratin and negative staining with melanocytic and mesenchymal markers. Based on these results, the case was diagnosed with MSC SCC. The myxofibrosarcoma, malign peripheral nerve sheath tumour, spindle cell atypical fibrocarcinoma and spindle cell melanoma should always be considered in the differential diagnosis of MSS SCC. Conclusion: The differential diagnosis of MSC SCC’s should be made by using melanocytic and mesenchymal markers in order to distinguishit from all other potential tumours. The diagnosis should be confirmed by using epithelial markers. E-PS-05-013 Minimal deviation melanoma: a rare case study report D. Anestakis 1 , M.I. Givannakis 2 , P. Konstantinidou 1 , F. Louka 1 , E. Zagelidou 3 1 Department of Autopsy Histopathology, Lab. of Forensic Medicine and Toxicology, Aristotle University of Thessaloniki, Greece, 2 Surgical Department , General Hospital "AHEPA", Thessaloniki Greece, 3 Thessaloniki Forensic Service, Thessaloniki, Greece Background & Objectives: Minimal deviation melanomas, also called borderline melanocytic lesion, are uncommon nevomelano-cytic tumours of indeterminate risk that appear as pigmented or non-pigmented skin nodules. They are typically lesions that satisfy the requisites for vertical growth. In borderline variants, they form an expansile nodule that is confined to a widespread papillary dermis. If they form an expansile nodule and infiltrate the reticular dermis, they are minimal deviation melanomas without the borderline qualification. They differ cytologically from the common aggressive melanomas. Methods: This report describes a case of minimal deviation melanomas involving on the scalp in a 72-year-old man. The patient presented with a skin nodule of scalp, simple excision of the tumour was performed. Results: Histological and the immunophenotype findings were compatible with minimal deviation melanoma. In the follow-up, after three years no recur or metastasis appeared. In the follow-up, after three years no recur or metastasis appeared. Conclusion: In our experience, they may rarely recur or rarely metastasize. These tumours are mostly observed in young adults and older children and are clinically diagnosed as Spitz nevi, hemangiomas, or malignant melanomas. It may originate from a pre-existing mole, or from normal skin (a new growth type). Minimal Deviation Melanoma of Skin tumours is said to have a ‘borderline’ behaviour. The most common treatment is surgery. Tumour metastasis is not observed very often and recurrences are uncommon after surgery. E-PS-05-014 Muir-Torre Syndrome: a rare hereditary condition C. Faria 1 , M.J. Julião 1 , V. Almeida 2 , F. Ramalhosa 1 , J. Fraga 1 , A. Lai 1 , R. Almeida 3,4 , M.B. Pimentão 1 , H. Moreira 3 , R.C. Oliveira 1 , M.A. Cipriano 1 1 Centro Hospitalar e Universitário de Coimbra, Portugal, 2 Institute of Anatomical and Molecular Pathology, Faculty of Medicine of the University of Coimbra, Portugal, 3 Centro Hospitalar e Universitário de Coimbra - Pathology Department, Portugal, 4 Faculty of Medicine in Coimbra, Portugal Background & Objectives: Muir-Torre syndrome, a rare autosomal dominant condition, is caused by germline mutations in the DNA mismatch repair (MMR) genes, MLH1, PMS2, MSH2 and MSH6 genes. This syndrome is considered a phenotypic variant of hereditary nonpolyposis colorectal carcinoma syndrome (HNPCC, Lynch syndrome) and is characterised by the association of at least one sebaceous skin tumour and/or keratoacanthoma and at least one visceral malignancy. Methods: We describe the case of a 49-year-old woman with a previous diagnosis of pancreatic carcinoma in 2015 and with a right inferior palpebral lesion of rapid growth developed three years later. Results: Histopathological examination revealed a sebaceous skin neoplasia with lobulated pattern, composed by two cellular populations, one central with a clear cytoplasm and a monotonous nucleus, and a second population of peripheral basaloid cells. The stroma is scant and edematous with congestive blood vessels. The mitotic activity is low and there were not areas of tumour necrosis. Immunohistochemistry study showed positivity for EMA and negativity for CEA; with immunoreaction for Ki67 limited to the basal cell layer. The neoplastic nucleus also retained positivity for MLH1 and PMS2 and had complete loss of MSH2 and MSH6. Conclusion: The diagnosis is a sebaceous adenoma with microsatellite instability that is related to germline mutation of Muir-Torre syndrome. Particularly this patient was previously diagnosed with a pancreatic ductal carcinoma although the internal malignancies most frequently associated with this syndrome are colorectal, ggynaecological and urothelial cancers. So genetic testing and preventive cancer screening program alongside clinical criteria should be studied for these patients. E-PS-05-015 A rare lesion of ear; Merkel Cell Carcinoma S.Y. Celik 1 , O. Ilhan Celik 1 , Y. Dere 1 1 Mugla Sitki Kocman University, Faculty of Medicine, Department of Pathology, Turkey Background & Objectives: Merkel Cell Carcinoma(MCC) is a rare, aggressive, cutaneous neuroendocrine neoplasia with a high mortality rate. It is generally seen in sun-exposed skin of head, neck and extremities in older adults with light skin. It may present at an earlier age in immunocompromised individuals like HIV-infected patients, organ transplant recipients and patients with hematologic diseases. Methods: A 71-year-old male suffering from a rapidly growing, 5cm, fixed, subcutaneous, nodular mass on his left auricle was referred to oto-rhino-laryngology clinic. An incisional biopsy demonstrated a necrotic tumour composed of small, uniform, round cells with high nucleus-to-cytoplasm ratio, round vesicular nuclei with ‘salt and pepper’ chromatin, scarce cytoplasm and high mitotic index. Results: Tumour cells were positive for Cytokeratin20, chromogranin A, Neuron-specific-enolase and synaptophysin and negative for Cytokeratin7, CD45, TTF-1, s100, Desmin, Myogenin, p63, Melan A. Ki67 index was about 50%. The lesion was diagnosed as MCC. Later the tumour is completely excised and ipsilateral lymph nodes of the neck were dissected. Three of the lymph nodes were metastatic. Radiotherapy was added to the surgical treatment. Conclusion: MCC is a very rare, aggressive tumour of epithelial and neuroendocrine origin that usually presents as a painless, exophytic nodul with a poor prognosis, including high rates of metastasis, recurrence and mortality. As it forms a banal-appearing lesion, the diagnosis of MCC is rarely suspected at the time of biopsy. The treatment of it is surgical excision and sometimes adjuvant radiotherapy and/or chemotherapy. Immunotherapy and targeted therapies are the other treatment methods which have been investigated. E-PS-05-016 Cutaneous infiltrate of a B chronic lymphocityc leukemia in two patients with an atypical fibroxanthoma and squamous cell carcinoma: two case reports and review of the literature A. Sobrino Prados 1 , C. Yus Gotor 2 , N. Torrecilla Idiope 2 , M.J. Viso Soriano 1 , J.I. Franco Rubio 2 , H.P. Almanzar Comas 1 , S. Bakali Badesa 1 , R.I. Bermudez Cameo 1 , î Arellano Álvarez 1 , N. Estrada Mallarino 1 , B. Cazaña Pèrez 2 , M. Pastor Adiego 2 1 Hospital Universitario Miguel Servet Zaragoza, Spain, 2 Hospital Universitario Miguel Servet, Spain Background & Objectives: Cutaneous infiltrate of a B chronic lymphocityc leukemia (B-CLL) is an infradiagnosed condition, in which clinical data and a methodic sample analyse is needed for making a correct diagnosis. Reviews in the literature suggest neoantigens and cytokines recognition and an immunosupressive microenvironment might explain the cause of the association of B-CLL and cutaneous neoplasms. Methods: Two 82-and-83-years-old-patients presented two lesions (0,9 and 1,2 cm size) in sun-exposed skin, which were completely excided, in 2018 in Hospital Universitario Miguel Servet in Zaragoza. Both suffered from a B-CLL for years, with lymphocytosis as the only clinical manifestation. Results: The H-E sections showed an atypical fibroxanthoma (AFX) and a squamous cell carcinoma (SCC) surrounded by an homogeneous infiltrate of mature B lymphocytes, which stained for CD20, CD79 a, CD5 and CD23. Therefore, patients were diagnosed of an AFX and SCC respectively with a cutaneous infiltration by B-CLL. Patients with B- CLL have an increased risk of devoloping neoplasms, probably due to the immunosupresive environment caused by the B-CLL. Besides, neoplasic lymphocytes infiltrate more frequently tumours or other inflammatory conditions taking place in the skin. The most common neoplasms associated with B-CLL are SCC, basocelular carcinoma and actinic queratosis. These have a higher risk of recurrences and it is recommended the surgical margins to be wider. Conclusion: Further research is necessary for improving our knowledge about the etiopathogenic mechanisms and the prognosis they may have and therefore, provide the best treatment options to patients. E-PS-05-017 Stepwise progression of proliferating pilar tumour and trichilemmal carcinoma from pilar cysts is associated with p53 loss: a case report L. Ahmed 1 , R. Hejmadi 1 , M. El-Shafie 1 , K. Kok 2 , O. Cain 1 1 University Hospitals of Birmingham NHS Trust, Cellular Pathology Queen Elizabeth Hospital, United Kingdom, 2 University Hospitals of Birmingham NHS Trust, Plastic and Burns department, Queen Elizabeth Hospital, United Kingdom Background & Objectives: Pilar (trichilemmal) cysts are commonly encountered specimens in routine diagnostic practice and only very rarely show atypical features. There is some debate as to whether stepwise molecular changes accumulating in pilar cysts gives rise to proliferating pilar tumour and trichilemmal carcinoma, or whether these tumours develop de novo in the absence of a pre-existing pilar cyst. Methods: We present a case of a patient with seventeen scalp cysts removed in one large surgical excision. Histologically all showed trichilemmal differentiation, ranging from benign pilar cyst, through proliferating pilar tumour to trichilemmal carcinoma. P53 immunohistochemistry was performed on the tumour. Results: We were able to demonstrate loss of p53 expression on immunohistochemistry specifically in the malignant element. In contrast, non-malignant elements showed patchy wild-type staining. Conclusion: This case supports the hypothesis that stepwise molecular changes result in the development of proliferating pilar tumour and trichilemmal carcinoma from pilar cysts. In keeping with previous studies, p53 mutation may well be a critical step in this progression detectable by routine immunohistochemistry. E-PS-05-018 Aleukemic neonatal leukemia cutis preceding monocytic leukemia with a favourable outcome B. Sirine 1 , J. Pourchet 1 , S. Fraitag 2 , N. Sturm 1 , H. Gil 1 1 Grenoble Alpes University Hospital, France, 2 Enfants Malades Necker Hospital, France Background & Objectives: Leukemia cutis(LC)is defined by cutaneous infiltration by leukemic cells.In aleukemic LC,the invasion of the skin happens at least 1 month before the acute leukemia.The neonatal form of LC which occurs within 4 weeks of life is less frequent than adult LC.Neonatal leukemia has a poor prognosis usually fatal.We report an exceptional case of complete remission after aleukemic LC preceding acute leukemia with main objectives to describe epidemiologic,clinical,histological,molecular and prognostic features of aleukemic neonatal LC. Methods: A female newborn presented at birth for a few firm red-violaceous papulo-nodular lesions in the face and the trunk.Physical examination didn’t reveal other abnormalities.CBC and coagulation tests of umbilical cord blood and in the first 24 hours were normal.Cutaneous biopsy performed on 3rd day of life showed a dense dermal infiltrate composed of a monomorphous undifferentiated blast cells with nuclear dust. These cells stained positively for CD4,CD15,CD68,CD43,HLA-DR.Myeloperoxidase was negative.Molecular testing revealed rearrangement of the MLL gene with translocation t(9;11). Results: We concluded to a cutaneous monocytic leukemia cutis (AML-M5).Thirteen days later,cerebrospinal fluid examination and bone marrow aspirate were normal, however, the peripheral blood smears showed the presence of monoblasts(14%).A close biological follow-up was mandatory.On the 31th day of life,the patient presented anemia, hyperleukocytosis(54,6x10 9 /L),elevated blasts(28%)and monocytes(18%).Urgent administration of multiple drug induction chemotherapy(ELAM 02 protocol)was followed by complete remission and clearance of cutaneous lesions on day 28 of life. Conclusion: LC is common in the ALM-M5 leukemia but its neonatal form has very rarely been described.Neonatal LC without other clinical signs has been reported in a few patients.Cutaneous biopsy and molecular testing is mandatory for diagnosis and typing of the disease.The favourable outcome of our patient is exceptional. E-PS-05-019 Pseudovascular squamous cell carcinoma: case report of an elusive entity and potential diagnostic pitfall T.A. Georgescu 1 , A.C. Lisievici 2 , A. Dumitru 3 , M. Sajin 4,5,6 , M. Costache 3,7 1 Department of Pathology, Bucharest Emergency University Hospital, Romania, 2 Carol Davila University of Medicine and Pharmacy, Bucharest, Romania, 3 Department of Pathology, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania, 4 SUUB, Romania, 5 UMF Carol Davila, Romania, 6 European Society of Pathology, Romania, 7 Department of Pathology, Emergency University Hospital Bucharest, Romania Background & Objectives: Pseudovascular squamous cell carcinoma was initially described in 1992 by Nappi, Barnejee and their collaborators, as a rare variant of cutaneous acantholytic squamous cell carcinoma which occurs on sun-exposed areas of middle-aged or elderly patients and can easily be mistaken histologically for angiosarcoma or an ulcerated metastasis of adenocarcinoma. Methods: We present the case of a 78-year-old male presenting to our clinic with an exophytic tumour of 12/7/5mm with extensive surface erosion, located on the left thigh. After clinical examination, the patient was subjected to surgical excision and the specimen was sent to the Department of Pathology for histopathological examination. Results: Microscopically, the tumour was composed of interanastomosing cord-like sheets of plump epithelial cells with vesicular and hyperchromatic nuclei forming pseudolumina and hobnail aspects. No foci of squamous differentiation or clear derivation from the surface epithelium were observed. Tumour cells were diffusely positive for AE1/AE3, CK5/6, p63 and Vimentin and completely negative for SMA, desmin, myogenin and S-100. In contrast to angiosarcoma, the tumour cells were also invariably negative for endothelial cell markers such as factor VIII-related antigen, CD31 and CD34. Conclusion: Based on the clinical, morphological and immunohistochemical aspects, the final diagnosis of pseudovascular squamous cell carcinoma has been established. Although the general outcome of this particularly rare variant is not very well studied, its recognition is extremely important due to the potential confusion with angiosarcoma, which yields a completely different clinical outcome. E-PS-05-021 Subcutaneous atypical ossifying fibromyxoid tumour with dermal involvement and mosaic loss of INI-1 expression: a case presentation P.I. Stinga 1 , A. Cioroianu 1 , S. Iacob 2 1 Colentina University Hospital, Romania, 2 Personal Genetics, Romania Background & Objectives: Ossifying fibromixoid tumour(OFT) is a rare soft tissue tumour with unusual dermal involvement, of uncertain lineage of differentiation, harboring particular histological and immunohistochemical features, as well as newly discovered molecular signatures. Three subtypes have been described-typical,atypical,malignant, based on cellularity,nuclear grade,mitotic index. Owing to its rarity,this entity poses vexing diagnostic challenges. Methods: We present the case of a 48 year-old male patient with a 7 years clinical course of a 60mm superficial subcutaneous mass of the trunk(subscapular region), diagnosed elsewhere as extraskeletal myxoid chondrosarcoma. Microscopy revealed a well-circumscribed,multinodular proliferation, arising in the subcutis, focally extended into the deep dermis, compound of small,round to spindle-shaped, mild pleomorphic cells with vesicular nuclei, eosinophilic cytoplasm, arranged in cords/trabeculae/clusters, imbedded in an fibromyxoid matrix, surrounded by a peripheral shell of lamellar bone;the cellularity was classified as intermediate and the mitotic index was 3/50HPFs. The immunohistochemical study revealed S100 diffuse positivity and focal GFAP, SMA,NSE,CD56 positivity; others markers performed(CD34,EMA,Desmin) were negative. INI-1 stain showed mosaic pattern staining. A diagnosis of an atypical OFT was made. Results: Molecular testing was elsewhere done, the result sustaining the diagnosis of OFT.On subsequent follow-up, the patient is alive and well, without signs of recurrence or metastasis after 1 year from the surgery. Conclusion: OFT is a peculiar neoplasm, often located in the superficially soft tissue, with infrequent dermal involvement and potentially aggressive behavior, recently included in the group of translocation-related lesions; the entity should be taken in consideration in the differential diagnosis of the superficial soft tissues tumours, often encountered in dermatopathology practice. This work was supported by a grant of Romanian Ministery of Research and Innovation, CCCDI-UEFISCDI, project number 61PCCDI⁄2018 PN-III-P1-1.2-PCCDI-2017-0341, within PNCDI-III. E-PS-05-022 Melanocytic matricoma: a case report of a rare entity G. Morgantetti 1 , G.A. Medeiros 1 , S.B.G. Hosseini 1 , M.L. Balancin 1 , M.E.d.A.S. Yamashita 2 1 University of Sao Paulo, Brazil, 2 Barretos Cancer Hospital, Brazil Background & Objectives: Melanocytic matricoma is a rare form of pigmented follicular neoplasm with both matrical and melanocytic components, first reported in 1999 by Carlson et al. Since its first publication, few cases have been published in the current scientific literature. Usually associated with hyperpigmented lesions appearing at sun-damaged skin of adults, melanocytic matricoma is rarely listed as the most probable diagnosis based on clinical examination alone, due to its very low incidence and lack of pathognomonic epidemiologic, clinical or dermathoscopic aspects. Microscopically, the lesion consists of a well circumscribed hypercellular nodule composed of a biphasic cell population: an epithelial phase composed of both matrical and supramatrical cells with clustered shadow cells and a melanocytic one, composed of dendritic melanocytes. The main clinical differential diagnoses are hemangioma, pigmented basal cell carcinoma and melanoma, while the main histopathological pitfall resides in the differentiation of melanocytic matricoma with matricoma or pigmented pilomatricoma. The present report aims to contribute with the current clinical, histological and immunohistochemical knowledge of the disease. Methods: A 42 year old female patient presented to the Ribeirão Preto Clinics Hospital (HCFMRP-USP) Dermatology Outpatient Clinic with a 0,9 cm forearm pigmented nodule. It showed no ulceration or irregular pigmentation. Excisional biopsy was performed under the clinical hypothesis of pigmented basal cell carcinoma. The biopsy material was submitted for histopathological examination, fixed in buffered formalin, embedded in paraffin and routinely stained with hematoxylin-eosin. Immunohistochemical study was performed with antibodies targeted to CEA, Chromogranin, CK5/6, HMB45, MelanA, p63, S100 and Synaptophysin. Results: Microscopically the lesion consists of a pigmented nodular tumour of well-defined borders composed of biphasic celullar components: (1) matrical cells that contain ovoid nuclei and frequent conspicuous nucleoli, with an intermediate nuclear-cytoplasmic ratio; (2) dentritic melanocytic cells that are elongated and pigmented (Figure 1). Clusters of ghost cells can be found dispersed through the lesion (Figure 2). Cysts that contain hyaline proteinaceous fluid are sparse. There is no necrosis or mitotic figures. The adjacent dermis show solar elastosis and a mild dermal mononuclear inflammatory infiltrate. The immunohistochemical profile of the neoplasm showed positivity to p63, with focal expression of high molecular weight cytokeratins (CK5/6) of the epithelial matrical component (Figure 3). MelanA, HMB45 and S100 stained positive in the dendritic melanocytes (Figure 4). There was no reactivity of CEA, CK20, Chromogranin or Synaptophysin antibodies. Conclusion: Melanocytic matricoma is a very rare biphasic neoplasm composed of matrical cells admixed with dendritic melanocytes, with few case reports and series of cases presented in current scientific literature. With the present case, we expect to contribute with useful clinical and pathological data to the current scientific knowledge of this rare entity. E-PS-05-023 Mycosis fungoides bullosa: a case report Î Yalçın 1 , A. Dobral 1 , S. Yıldırım 2 1 Istanbul Okmeydani Training and Research Hospital, Turkey, 2 Istanbul Maltepe University- Medical School, Turkey Background & Objectives: Mycosis fungoides is the most common type of cutaneous T-cell lymphoma which can be presented with different clinical and histological forms. Mycosis fungoides bullosa is a rare variant of mycosis fungoides. Therefore we report a case of mycosis fungoides bullosa and review the relevant literature. Methods: We present a case of mycosis fungoides in a 75-year-old man who presented with erythematous plaques on all extremities histologically diagnosed as mycosis fungoides bullosa which is incompatible with the clinical apperance. Results: Histopathology revealed extensive lichenoid changes with intraepidermal bullae. Atypical lymphocyte infiltration was present at the dermoepidermal junction, in bulla. Conclusion: Although mycosis fungoides bullosa is extremely rare, it is regarded as an important clinical subtype of cutaneous T-cell lymphoma. Mycosis fungoides bullosa represents an aggressive form of mycosis fungoides and is associated with a poor prognosis. Mycosis fungoides bullosa is a rare occurance which is always manifested in vesiculobullous eruptions. We describe a 75-year old man with histopathologic diagnosis of mycosis fungoides bullosa who developed plaques lacking blister formation on normal appearing skin.Our case is rare in the literature with the incompatible clinical and histological diagnosis of the rare variant ‘mycosis fungoides bullosa’. E-PS-05-024 Cutaneous biphasic sarcomatoid basal cell carcinoma: report of a rare entity and review of the literature M. Mellouli 1 , S. Graja 1 , S. Makni 1 , N. Gouiaa 1 , A. Ben Mabrouk 1 , Z. Lajmi 1 , M. Zghal 1 , M. Walha 1 , T. Sallemi-Boudawara 1 1 Department of Pathology, Habib Bourguiba Hospital, Sfax, Tunisia Background & Objectives: Biphasic sarcomatoid carcinoma is an uncommon biphasic neoplasm that has been reported in diverse anatomical sites. The tumour is composed of a malignant epithelial component intimately associated with a malignant mesenchymal component, which may be homologous or heterologous. Only 47 cases of primary cutaneous biphasic sarcomatoid basal cell carcinoma (BSBCC) have been reported in the English literature. We report a further one case of BSBCC of the scalp and include the clinical, histological and immunohistochemical features. Methods: The histological and immunohistochemical features of BSBCC of the scalp are described with a review of the related literature. Results: A 65-year-old man presented with an elevated and ulcerated lesion on the scalp measured 20×15×6 mm. The lesion was surgically excised. Histology showed basal cell carcinoma intimately admixed with a sarcomatous component composed of spindle and oval atypical cells with vesicular nuclei and quit high mitotic count. There was no heterologous stroma. Immunohistochemical analysis showed these cells to be positive for vimentin and negative for keratin and HMB45. The diagnosis of BSBCC was made. In our case, tumour was completely resected with no recurrence or metastases. Conclusion: The histogenesis of BSBCC has been extensively debated. Four main theories have emerged, the most widely accepted was that the sarcomatous component is a metaplastic transformation of the carcinomatous component which would confer an increase in aggressive potential to the tumour. In view of this potential, complete resection is recommended. E-PS-05-026 Morphological and immunohistochemical studies of Kaposi sarcoma V. Filatov 1 , J. Omarova 1 , T. Bezuglova 2 , M. Mnikhovich 3 , A. Asaturova 4 , V. Kometova 4 1 Pirogov Russian National Research Medical University, Russia, 2 Research Institute of Human Morphology, Russia, 3 Research Institute of Human Morphology (Moscow), Russia, 4 Federal State Budget Institution National Medical Research Center of Obstetrics, Gynaecology and Perinatology Ministry of Healthcare of the Russian Federation (Moscow), Russia Background & Objectives: The differential diagnosis of Kaposi sarcoma (KS) includes many tumours such as dermatofibroma, histiocytoid hemangioma, kaposiform hemangioendothelioma, angiosarcoma. Methods: Biopsy material from 7 HIV negative patients (age 45-75 years), 3 women (51, 32%) and 4 men (48, 68%), was studied. In 6 cases (72,37%) patients complained of skin tumours. In 1 case (27,63%) diagnosis was established post mortem. Results: Immunohistochemical studies have shown monomorphic expression of CD34 by endothelial cells while expression of von Willebrand factor was heterogeneous, cells were generally negative for CD31. Endothelial cells and myofibroblast-like cells have shown focal intensive nucleocytoplasmatic expression of HHV8. Myofibroblast-like cells demonstrated intensive Ki-67 positivity. Additional markers (IgL(lambda), IgL(kappa), CD38, CD3, CD79a, CD30) were used. Cells demonstrate intensive IgL(lambda), IgL(kappa), CD38 cytoplasmatic expression, CD3, CD30 membrane and cytoplasmatic expression and membrane expression of CD79a. Conclusion: Pathomorphological diagnostics of KS should include histological study with consideration of chaotic character of angiogenesis, proliferation of spindle cells with endothelial markers, mononuclear cell infiltration, and immunohistochemical study with CD34, CD36, CD31, Von Willebrand factor, and Ki-67. Additional markers (IgL(lambda), IgL(kappa), CD38, CD3, CD79a, CD30) in pathomorphological practice for differential diagnosis. E-PS-05-027 Infundibulocystic basal cell carcinoma: an unusual variant at an unusual age in sun protected skin M. Mc Cabe 1 , J. Fitzgibbon 1 1 Cork University Hospital, Ireland Background & Objectives: Infundibulocystic basal cell carcinoma (BCC) is a rare variant with a distinct underlying mutation which contains elements of follicular differentiation. <1% of BCC occurs in the vulva. Two previous cases of vulval infundibulocystic BCC have been described in the literature. The first was a woman with widespread BCCs due to a germline mutation in a gene downstream from Sonic Hedgehog. The other was an elderly woman with concurrent Paget’s disease. Methods: We present the case of a 28-year-old woman who presented with a left upper labial cyst which, on histological examination, was revealed to be an infundibulocystic BCC. The specimen was received labelled as “Tiny left labial cyst.”. Results: Grossly, the specimen was a pale, round, smooth piece of tissue measuring 6x4x3mm. The entire mass was embedded. At low magnification, a well-circumscribed, palisading tumour was seen, consisting of infundibular-like structures with keratin plugs and anastomosing nests of basaloid cells, and tumour–stroma retraction. The tumour was superficially located and at the margin. At higher magnification, the tumour cells had a high nuclear:cytoplasmic ratio with pleomorphism, hyperchromatic nuclei, and inconspicuous nucleoli. Conclusion: Infundibulocystic BCC is a less aggressive subtype whose underlying mutation differs from that found in more common forms. This case highlights the heterogeneity of BCC and in contrast with the previous reports, occurred in isolation in a young woman. E-PS-05-028 Combined cutaneous tumours with melanoma component. Case report and literature review A. Abuomar 1 1 Hospital General universitario de Elda, Alicante, Spain Background & Objectives: Combined cutaneous tumours (CCTs) with a melanoma component are very rare with only 49 cases in the literature up to our knowledge. Squamomelanocytic CCTs are the most frequent followed by basomelanocytic CCTs and trichoblastomelanoma. We present a case of malignant basomelanocytic tumour and a literature review. Methods: A 37 years old woman with brown eyes and skin phenotype III, a medical history on hypothyroidism and frequent sunburns. Patient arrived to our hospital complaining of that his year old left thigh nevi changed its color and size in the last week. Dermatology examination revealed a 5x5 mm with skin lesion on the anterior face of the left thigh with suspected signs on dermatoscope. Skin melanoma was suspected. elliptical incision of the lesion with narrow margins was performed. Results: We received a skin elips of 10x5x5 mm with a pigmented lesion of 5x5 mm. Microscopic examination showed a skin with a neoplastic proliferation of basaloid epithelial cells with mild atypia admixed with severely atypical large melanocytes colonized the epitelial component and showing lentiginous and inflitrative growth pattern. Melanocytic component showed positive stain for S100, Melana A and HMB45, while epithelial component showed CK AE1-3 expresion. Cells with double expression of S100 and CK were observed. Conclusion: The histogenesis of CCTs is not clear. 11q13 amplification in both components supports the theory of dual differentiation from a common progenitor cell. Studies showed that CCTs have better prognosis in comparison to melanomas with the same pathological stage. E-PS-05-029 Sweet syndrome like neutrophilic dermatosis as an initial presentation of new-onset bullous systemic lupus erythematosus: a case report M. Zivanovic 1 , A. Vizjak 1 1 Insitute of Pathology, Medical Faculty Ljubljana, University of Ljubljana, Slovenia Background & Objectives: To report a case of bullous systemic lupus erythematosus (SLE) that presented initially as a neutrophilic dermatosis (ND) in an adult male patient with antiphospholipid syndrome. Methods: 30-year-old male presented with annular erythematous skin eruptions on his trunk and thighs that clinically raised suspicion of urticarial vasculitis. We examined the skin lesion from right thigh by light microscopy and direct immunofluorescence, followed by indirect immunofluorescence (ELISA). Results: Histopathological examination revealed diffuse mild to moderate interstitial and perivascular dermal infiltrate composed predominantly of neutrophils, without accompanying fibrinoid necrosis of vascular walls or other histological features of presumed vasculitis. Direct immunofluorescence showed so called »full house« deposition of IgA, IgG, IgM, C3 and C1q along dermo-epidermal junction, in vascular wall of small blood vessels and also along conective tissue fibers in dermis. These findings were suggestive of SLE but also of possible hipocomplemented urticarial vasculitis. Indirect immunofluorescence testing on blood sample was negative for the presence of anti-C1q antibodies. Serological findings were highly suggestive of SLE. Less than one month after the initial symptoms patient developed widespread vesiculobullous skin eruption. Conclusion: While the association of ND and autoimmune connective tissue diseases is well recognized, Sweet syndrome like ND as a presenting sign of SLE is reported only in a handful of cases, mostly in women. Even tough ND often presents in idiopathic fashion, it is important to think about possibility of underlying SLE, especially in younger patients. E-PS-05-031 Cladophialophora Immunda: an extremely unusual infectious agent for chromoblastomycosis J.I. Franco 1 , A. Sobrino 2 , N. Torrecilla 2 , C. Yus 2 , P. Cerro 3 , R. Baldellou 3 , C. López 4 , M.I. Millán-Lou 4 1 Hospital Universitario Miguel Servet Zaragoza, Spain, 2 Anatomía Patológica. Hospital Universitario Miguel Servet, Spain, 3 Dermatología. Hospital Universitario Miguel Servet, Spain, 4 Microbiología. Hospital Universitario Miguel Servet, Spain Background & Objectives: Chromoblastomycosis, described for the first time in 1911, with few cases reported in Spain, is a deep mycotic infectious disease, resulted from inoculation of dermatiaceous fungi after a traumatic injury, specially in males with a wide range of age. It is a slow-course disease, predominantly reported in tropical or subtropical areas. Clinically, it can simulate a malignant lesion, such as squamous cell carcinoma. It is a disease with an easy diagnosis that needs microbiological correlation in order to stablish a specific treatment. Methods: We report the case of a 56-year-old male with history of kidney transplant, with a fastly-growing verrucous lesion, asymptomatic, located on the right foot. An incisional biopsy was performed and a sample for microbiological culture was taken. Results: Histological examination of the biopsy showed an ulcerative lesion, with pseudoepitheliomatous hyperplasia and superficial granulomatous process, with multinucleated giant cells containing small, from 6 to 12 μm, round dark-coloured structures, evidenced without any special stain. Subsequent microbiological culture allowed typify the microorganism as Cladophialophora Immunda. Conclusion: Chromoblastomycosis,is a very uncommon disease in a non-tropical country and Cladophialophora Immunda is an extremely unfrequent microorganism among the dermatiaceous fungi, causal agents of this entity. The posibility of this diagnosis should be taken in consideration in a verrucous and ulcerated lesion, from a tropical or subtropical climate country-native patient, specially in situation of immunosupression. Microbiological cultures should be granted in order to typify the microorganism and stablish the best treatment. E-PS-05-032 Epidermolytic ichthyosis: study of a family with skin fragility and palmoplantar keratoderma A. Sobrino Prados 1 , N. Torrecilla Idiope 2 , C. Yus Gotor 2 , P. Cerro 2 , Y. Gilaberte 2 , J. Forteza 2 , J.I. Franco Rubio 2 , M.J. Viso Soriano 1 , S. Bakali Badesa 1 , H.P. Almanzar Comas 1 , R.I. Bermudez Cameo 1 , N. Estrada Mallarino 1 , î Arellano Álvarez 1 1 Hospital Universitario Miguel Servet Zaragoza, Spain, 2 Hospital Universitario Miguel Servet, Spain Background & Objectives: Epidermolytic ichthyosis (EI) is a rare autosomal dominant genodermatosis, affecting the keratinization and suprabasal maduration of keratinocytes and is generally associated with mutations in the keratin 1 and 10 genes. Symptoms in newborns are bullous lesions, erythroderma and desquamation, followed by different degrees of skin fragility in adulthood and sometimes, palmoplantar keratoderma. Although in newborns there is an increased risk of infections or sepsis, the prognosis is usually good, but it depends also on the severity of each case . Methods: One-month-old male presented bullous lesions in buttocks, thighs and perioral area since birth. His mother, grandmother and uncle have a history of palmoplantar keratoderma along with skin fragility with a tendency to suffer bullous and ulcerative lesions. Two biopsies, an ultraestructural and genetical study were necessary to reach the diagnosis. Results: Newborn biopsies showed a subcorneal blister with eosinophils and negative immunofluorescence. In the second biopsy of the mother, a characteristic perinuclear cytoplasmic vacuolization of keratinocytes of higher strata was observed. Ultraestructural study had images of epidermolysis of the epidermocytes, being compatible with the EI. Massive sequencing revealed a mutation in gen KRT1, p.Val198Glu; c.593>A, not described before in literature, and usually associated with palmoplantar keratoderma. Conclusion: - EI is a rare genodermatosis with a broad clinical, histological and prognostic spectrum, due to the different mutations in KRT1 and KRT10. - KRT1 alterations are associated with palmoplantar keratoderma. - Further research is needed to improve our knowledge of this entity. E-PS-05-033 Epidermodysplasia verruciformis: an unusual diagnosis S. Yacoub 1 , S. Mistiri 1 , N. Abdessayed 1 , B. Sriha 1 , M. Mokni 1 , D. Chiba 1 1 Department of Pathology Farhat Hached Hospital, Tunisia Background & Objectives: Epidermodysplasia verruciformis (EV) is a very rare genetic dermatologic condition, HPV related, causing an increased risk of cutaneous dysplasia and malignancy. The lesions of EV tend to exhibit a characteristic histopathologic appearance. We describe a rare case of EV. Methods: A 23 year-old female presented for management of a 3 cm waxy-brown verrucous plaque on the forehead that appeared 1 year before. A biopsy of the lesion was performed. Results: The resected specimen was fragmented. Histopathologic examination of these lesions showed a thickened epidermis with a verruciform architecture. The epidermis was aconthotic, covered by a marked orthokeratosis. Numerous koilocytic cellular atypia was present associated to cluster of vacuolated cells with bubbly bluish cytoplasm. The superficial dermis showed a mild dermis infiltrate. Conclusion: EV is a premalignant entity, that needs a close dermatologic monitoring. E-PS-05-034 Erithema Elevatum Diutinum - a rare and often misdiagnosed entity D. Vinha Pereira 1 , J. Ferreira 1 , A. Robson 1 and J. Costa Rosa 1 1 Pathology Department, Instituto Português de Oncologia de Lisboa Francisco Gentil, Lisbon, Portugal Background & Objectives: Erythema (red) elevatum (elevated) diutinum (persistent) - EED is a rare middle-age chronic cutaneous vasculitis of unknown etiology associated with autoimmune, infectious and hematological diseases. Many clinical and histological mimics can be recognized, such as inflammatory conditions, in early stages (e.g.: granuloma faciale, Sweet´s syndrome) or neoplasias, in later stages (e.g.: dermatofibroma, myxoinflammatory fibroblastic sarcoma). Methods: We report two cases clinically diagnosed as a neoplasia (first case) and epidermal cysts/keloid scars (second case). Results: Two women (aged 42 and 50) with no relevant medical history presented with slowly developing multiple cutaneous limb nodules (first case) and facial papules (second case). Histologically, both cases revealed superficial and deep dermal mixed inflammatory infiltrates (more prominent on the second case), with abundant neutrophils and scattered eosinophils; neutrophilic vasculitis and leucocytoclasis were present; fibrosis was particularly dense on the first case. Special stains for fungi and mycobacteria were negative. A diagnosis of EED was performed (later and early stages, respectively). Although the first patient had a history of recurring limb nodules (outside our institution), 15 months after this excision, she remains disease free. The second patient developed similar lesions at the same location after 6 years. There is no evidence of other systemic diseases in both cases. Conclusion: EED diagnosis is challenging and requires histological and clinical correlation, because of its strong association with systemic diseases. Isolated cases can also exist. E-PS-05-035 A non-scalp neurocristic cutaneous hamartoma with malignant transformation - a case report and review of literature C. Costa 1 , I. Gullo 1,2,3 , J. Pacheco 1,2 , J.M. Lopes 1,2,3 , E. Rios 1,2,3 1 Department of Pathology, Centro Hospitalar de São João, Porto, Portugal, 2 Department of Pathology, Faculty of Medicine of the University of Porto (FMUP), Porto, Portugal, 3 Institute of Molecular Pathology and Immunology at the University of Porto (Ipatimup), Instituto de Investigação e Inovação em Saúde (i3S), Porto, Portugal Background & Objectives: Neurocristic cutaneous hamartoma (NCH), a rare hamartomatous-type lesion of neural crest origin, characteristically unveils fibrogenic, melanocytic, and/or neuro-sustentacular differentiation. NCH displays predilection for the scalp, and may be congenital or sporadic. Despite few reported cases, up to 35% NCH (~40% congenital) developed malignant transformation. Herein we report a sporadic NCH with melanoma transformation and lymph node metastases. Methods: A 55-year-old-male with giant “bathing-trunk”-type pigmented lesion since his adolescence, which displayed recent rapid growth. Resection of two indurated subepidermal nodules was performed, then margins widening/sentinel node/inguinal lymph node dissection. Results: Histology revealed a complex lesion comprising cellular blue nevus-like and neurofibroma-like components, in a background of congenital intradermal nevus. One of the nodules disclosed nodular melanoma area without ulceration of epidermis. Five out of eleven lymph nodes dissected (including sentinel node) disclosed metastases. Immunohistochemistry revealed common features of neurofibroma and melanocytic components. Diagnosis: NCH with melanoma transformation. No BRAF mutations were detected. The patient was proposed for adjuvant chemotherapy/radiotherapy (recent case). Conclusion: NCH is rare and can develop melanoma over variable time course (15 to 67 years), due to etiopathogenesis that differ from low degree of cumulative sun damage skin melanomas. So far, 11 cases of malignant transformation (all as melanoma) NCH were reported (excluding the present case), 5 (~45%) of which developed metastases. E-PS-05-036 Quinquaud's decalvans folliculitis: a case report S. Ben Khalifa 1 , N. Abdessaied 1 , S. Chaieb 1 , Z. Nfikha 1 , A. Ben Abdelkader 1 , M. Mokni 1 1 Pathology Department of Fattouma Bourguiba Hospital, Monastir, Tunisia Background & Objectives: Folliculitis decalvans (FD) of Quinquaud is a rare chronic follicular inflammatory process, extremely resistant to treatment, causing follicular atrophy and subsequent hair loss. The etiology is still unknown. Methods: We report a case of FD diagnosed in the department of pathology of Farhat Hached hospital. Results: A 31-year-old man presented to dermatology department with a tumoural lesion on the scalp of 2 years duration, with progressive loss of hair. He had no medical history. Physical examination revealed a nodular alopecic lesion of the scalp, 2cm in size. Bacteriological and mycological findings were negative. Complete removal of the lesion was performed, and histopathological examination revealed a FD of Quinquaud. Conclusion: FD is a chronic form of deep folliculitis that usually occurs on the scalp as oval patches of scarring alopecia at the expanding margins of which are follicular pustules. Any or all of the hairy areas of the body may be involved. The etiology is unknown, although Staphylococcus aureus is sometimes cultured from the lesions. Initially there is a folliculitis; this is followed by disruption of the follicular wall and liberation of the contents of the follicle into the dermis. The dermis adjacent to the destroyed follicle contains a mixed inflammatory cell infiltrate. Plasma cells are sometimes present in the infiltrate, particularly in resolving lesions. Foreign body giant cells may form around the hair shafts lying free in the dermis. FD sometimes responds to oral antibiotics but usually relapses after interruption of therapy, sometimes with severe scarring. E-PS-05-037 Pretibial myxedema- a case report S. Jakovljević 1,2 , A. Fejsa Levakov 3,2 , L. Djurdjev 4 , V. Zečev 5 , L. Vujanović 1,2 , J. Sekulić 4 1 Clinic of Dermatovenereology Diseases, Clinical Center of Vojvodina, Novi Sad, Serbia, 2 Faculty of Medicine Novi Sad, University of Novi Sad, Novi Sad, Serbia, 3 Pathology and Histology Center, Clinical Center of Vojvodina, Novi Sad, Serbia, 4 General Hospital 'Đorđe Joanović', Zrenjanin, Serbia, 5 General Hospital 'Dr Radivoj Simonović' , Sombor, Serbia Background & Objectives: Pretibial myxedema is a form of cutaneous mucinosis. It is a rare, chronic dermatosis, caused by thyroid dysfunction. Methods: We present a 79-year-old female patient with chronic, symmetric, pretibial edematous, erythematous, yellowish plaques with affected skin resembling ‘peau d’orange’ followed by feeling of the weight in the legs. The anamnestic data revealed the presence of thyroid dysfunction and diabetes mellitus, cholelithiasis and nephrolithiasis, as well as arterial hypertension and ischemic cardiomyopathy. In order to determine the etiology of pretibial edema and accurate diagnosis, a skin biopsy was done and histopathological findings confirmed the diagnosis of pretibial myxedema. Results: The haematoxylin and eosin (H&E), Periodic Acid Schiff (PAS), Gomori and Giemsa staining were performed. Pathology analysis presented a diffuse atrophic and distinctly hyperkeratotic epidermis with flattened rete ridges. Dermis was expanded with granular appearance in lower two thirds due to abundant deposits of mucin widely separating collagen bundles. Capillary blood vessels were dilated, while sweat glands were of regular shape and distribution. Conclusion: Our report confirms association between pretibial myxedema and thyroid endocrinopathy. Histopathology is of crucial significance in differentiating pretibial myxedema from other clinically similar conditions such as stasis dermatitis. Due to prompt diagnosis and conduction of recommended therapy, the skin remission and good quality of life could be accomplished. E-PS-05-038 Merkel cell carcinoma, diagnostic experience in a reference hospital R. Lopez 1,2 , D.A. Suarez-Zamora 1 , L.E. Barrera-Herrera 3 , M. Rolon 1 1 Department of pathology and laboratories, Hospital Universitario Fundación Santa Fe de Bogotá, Bogotá, Colombia, 2 School of Medicine, Universidad de los Andes. Bogotá, Colombia, 3 Department of Pathology and Laboratories, Hospital Universitario Fundación Santa Fe de Bogotá, Bogotá, Colombia Background & Objectives: Merkel Cell Carcinoma (MCC) is a poorly differentiated neuroendocrine tumour with very low frequency, usually is located on the exposed skin and classically manifests with aggressive behavior and high recurrence and metastatic risk. We present the largest series of MCC to date in Latin America focusing on understand and clarify essential concepts for prompt diagnosis and management of this not well known and aggressive disease. Methods: We present a cross-sectional descriptive retrospective study in patients diagnosed with MCC at our University Hospital between October 2003 and October 2018, we present the demographic, clinical and pathological variables of these patients. Results: 36 patients with histopathological diagnosis of MCC, 20 (55.6%) were men and 16 (44.4%) were women, male: female ratio of 1.25: 1. The median age was 71.5 years and the age range was 17.0 to 87.0 years. 88.9% (32/36) of the patients were older than 50 years. The most frequent location was facial skin (27.8%), followed by metastasis with unknown primary site (25.0%) and skin of the lower limbs and hip ( 13.9%). The incidence rate of Merkel cell carcinoma at our university hospital was 0.72 cases per 100 000 people between October 2003 and October 2018. Conclusion: This is the largest series of MCC to date in Latin America, we conducted a complete histopathological analysis, our information is consistent with what is referred to worldwide regarding the clinical and histopathological characteristics. E-PS-05-039 Malignant complex (composite) adnexal cutaneous tumour mistaken for basal cell cancer: a case report E. Delic 1 , J. Redzepagic 2 , D. Spirtovic 1 , T. Ramovic 1 , N. Bilalovic 1 1 Clinical Center University of Sarajevo/ Clinical Pathology and Cytology, Bosnia and Herzegovina, 2 Clinical Center University of Sarajevo, Bosnia and Herzegovina Background & Objectives: Adnexal tumours of the skin are rare, heterogeneous group of tumours. Malignant tumours are even rarer than their benign counterparts. Here, we describe a metastatic complex malignant adnexal tumour of the skin in the axillary lymph node. Methods: Case presentation. Results: A 46-year-old male patient is sent from another hospital in our institution due to an enlarged lymph node in the right axilla and multiple masses in both lungs radiologically. Before this, the patient had the lesion on the face skin, which was surgically removed 5 years ago, diagnosed as basal cell cancer. Core needle biopsy of the lymph node is performed and histological examination reveals microscopic picture suspicious for metastatic skin cancer. The revision of the primary skin biopsy has been obeyed and the diagnosis of the malignant complex adnexal tumour with follicular, trichilemmal, sebaceous and ductal differentiation is established. During the diagnosis process, the patient died. Conclusion: Many histological subtypes of malignant adnexal tumours been described. These tumours are rare, locally aggressive, and have the potential for nodal involvement and distant metastasis, with a pore clinical outcome. Patients age under 50 requires a higher degree of suspicion for the diagnosis of basal cell cancer. The complex histology of the presented case emphasizes the importance of histopathological examination in the diagnosis and therapeutic management of malignant cutaneous adnexal tumours. E-PS-05-040 Dermal clear cell sarcoma: a very rare and confusing diagnosis A. Saidi 1 , R. Jouini 2 , F. Khanchel 2 , I. Hell 2 , W. Koubaa 2 , E. Ben Brahim 2 , A. Chedli-Debbiche 2 1 Pathology Department; Military Hospital for Instruction of Tunis, Tunisia, 2 Pathology Department; Habib Thameur Hospital, Tunisia Background & Objectives: Clear Cell Sarcoma (CCS) is a rare and aggressive tumour with melanocytic differentiation. It was first described by Enzinger as a tumour that mainly involves the tendons and fasciae of the distal extremities of the young- to middle-aged woman. It is characterised by the frequency of local recurrences and late metastases that explain its poor prognosis. Dermal location is much rarer. We report a new case of dermal CCS and discuss its anatomoclinical features Methods: Standard Histological study of the tumour with immunohistochemical analysis targeting the markers: Melan A, HMB45, P16, Pancytokeratin, Ki67, PS100, CD68, Fact13a, EMA, Calponin, Caldesmone. Results: We report the case of a 65-year-old female patient consulting for a 1.5 cm large pedunculated tumour with a smooth surface arising in the inner side of her right thigh. The mass has gradually increased in size since 8 months. After excision, histological examination shows that the dermis is entirely occupied by an ill-defined proliferation arranged in cellular bundles and clusters surrounded by collagen bands. Tumour cells are spindle shaped or epitheloid with often vesicular nuclei, otherwise hyperchromatic. The figures of mitosis are numerous. The tumour cells exhibit only a weak and focal positive PS100 staining with a proliferation index (Ki67) estimated at 5%. The diagnosis of dermal clear cell sarcoma was additionally confirmed by Prof. Mentzel (Germany). Conclusion: Dermal CCS is a rare, highly malignant soft tissue tumour, usually affecting young women and occuring most commonly in the extremities. Due to its rapid and aggressive evolution, it should always be considered in front of a fast-growing and rapidly ulcerating, cutaneous nodular lesion. Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-06 | Digestive Diseases Pathology – GI Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-06 | Digestive Diseases Pathology – GI E-PS-06-001 Arylsulfatase B as prognostic marker in colorectal cancer Z. Kovacs 1 , L. Banias 1 , I. Jung 1 , S. Gurzu 1 1 University of Medicine, Pharmacy, Sciences and Technology, Targu Mures, Romania Background & Objectives: Arylsulfatases are lysosomal enzymes with role in several metabolic processes. In normal colonic mucosa, Arylsulfatase B (ARSB) is present in the cell membranes. Few aspects are known about ARSB in colorectal adenocarcinoma (CRC). The aim of the paper was to evaluate the possible correlation between ARSB and clincopathological aspects of CRC. Methods: ARSB immunohistochemical expression (polyclonal, Abcam, dilution 1:50) was prospectively quantified in 45 CRCs. As membrane to cytoplasmic translocation was seen in tumour cells, compared with normal mucosa, cases were divided into three groups, based on cytoplasmic expression intensity and number of positive cells. Results: ARSB was more expressed in young versus old patients (p=0.0095) and slightly higher in cases with ulcero-infiltrative aspect, compared with polypoid tumours (p=0.0088). As regarding microscopic aspect, the ARSB intensity increased with tumour dedifferentiation, all of the G3/G4 cases showing high expression (p=0.041). It was also directly correlated with presence of lymph node metastasis (p=0.026) and lymph node ratio (14 cases out of 34 with a lymph node ratio <0.1 had low ARSB expression, p=0.026). Conclusion: In CRC, compared with normal mucosa, membrane to cytoplasmic translocation is characteristic. High ARSB intensity was correlated with increasing aggressiveness of CRC cancer, which underlines the possible role of this enzyme as a prognostic maker of CRC. This paper was supported by a Romanian Government-UEFISCDI Grant nr. PCCF20/2018 E-PS-06-002 AA Amyloidosis of the gastrointestinal tract associated with Waldenström´s Macroglobulinemia M. Garcia Martos 1 , C. Perna Monroy 2 , C. Prada Puentes 3 1 University Hospital Gregorio Maraño, Spain, 2 Univ. Hosp. Ramon y Cajal, Spain, 3 Univ Hosp Torrejon, Spain Background & Objectives: AL amyloidosis is a well-known complication of Waldenström´s macroglobulinemia (WM). AA amyloidosis is commonly associated with chronic inflammatory disorders. We present a case of gastrointestinal AA amyloidosis and WM. We show the importance of Congo red staining in bowel biopsies in patients with unexplained gastrointestinal tract symptoms. Methods: A 59-year-old male with WM and several months’ history of profuse diarrhea. He did not have fever, lymphadenopathy, or any other systemic manifestations, neither autoimmune nor connective tissue disorders. The patient underwent a colonoscopy and multiple colonic biopsies. Results: Biopsy specimens from colon and rectum showed marked eosinophilic acellular material in the lamina propia and submucosa, with variable inflammatory infiltrated. This material was Congo red positive (showed apple-green birefringence under polarized light). Immunohistochemistry showed strong positivity for AA deposits, confirmed by immunoelectron microscopy. It was also detected high serum monoclonal IgM levels. Disease progressed with renal, pulmonary, cardiac, hepatic and bone marrow involvement. He began Rituximab therapy but he had a lower digestive hemorrhagic episode and die. Conclusion: Amyloidosis is a well-known complication of IgG related gammapathy but it is rare in IgM related gammapathy, including WM, and even rarer AA amyloidosis. Only a few cases have been reported of AA amyloidosis associated with WM. This association is seen in 5% of all gammapathy cases. Since each subtypes of amyloidosis requires different therapy, amyloid subtyping is crucial. E-PS-06-003 Clinical and morphological features of eosinophilic oesophagitis in patients with asthma L. Mikhaleva 1 , V. Golovanova 1 , V. Pechnikova 1 , O. Vasyukova 1 , E. Akopyan 1 , K. Midiber 1 , M. Gushchin 1 1 Research Institute of Human Morphology, Russia Background & Objectives: Eosinophilic esophagitis (EoE) is an immune-mediated condition, characterised by oesophageal dysfunction and eosinophil-predominant inflammation. Patients with EoE are more likely to suffer from atopic conditions such as asthma than others. The accepted threshold for eosinophil density for the EoE diagnosis is 15 eos/hpf. The research goal was to show EoE clinical and morphological features in patients with asthma. Methods: We observed 81 patients, 46 of which had controlled asthma of different severity and the rest of them represented the comparison group. Moreover, 15 autopsy cases were used in this study. Imaging (esophagogastroduodenoscopy), morphological (light microscopy), immunohistochemical and morphometrical methods were used. Additional EoE histological criteria are eosinophil microabscesses, basal zone hyperplasia, dilated intercellular spaces, eosinophil surface layering, papillary elongation, and lamina propria fibrosis. Results: Morphometrical study showed mucosal layer atrophy. The active role of macrophages and NK-cells and an SE4+ and CB8+ cells imbalance (SE4/SE8 <1) in the mucous membrane atrophy and sclerosis in the oesophagus and stomach were proven unlike the comparison group. EoE infiltration evaluation revealed a significant number of macrophages and NK-cells which correlates with the subepithelial sclerosis prevalence, as well as earlier mucosa atrophy and lamina propria sclerosis in the oesophagus than in the stomach and the duodenum. Conclusion: In conclusion, it is necessary to conduct a timely differential EoE diagnostics in patients with asthma, taking into account its frequency and EoE early development in these patients and its disabling complications. E-PS-06-004 A case of MiNEN arising in the rectum with metastases in a benign tumour I.A. Ungureanu 1 , A. Dumitru 2 , L.A. Ursache 1 , D.I. Enea 1 1 University Emergency Hospital Bucharest, Romania, 2 Department of Pathology, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania Background & Objectives: Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNEN) are rare entities defined by the presence of two morphologically different neoplastic components (each at least 30% of the tumour), including a neuroendocrine one. High-grade MiNEN are usually aggressive neoplasms with poor prognosis and the metastatic risk is correlated to the grade of the neuroendocrine component. In this paper we present the first case of a high-grade MiNEN metastasized in an ovarian serous cystadenofibroma. Methods: A 63 year-old female was hospitalized with a mass in the rectosigmoid junction, liver metastases and an ovarian mass. The patient underwent surgery and the primary tumour and the ovarian mass were both sent to gross examination. The microscopic analysis was performed on paraffin-embedded tissue samples stained with hematoxylin-eosin. Immunohistochemistry was performed for the following markers: ki-67, CK7, CK20, Chromogranin A, Synaptophysin, CD56, CDX2. Results: Microscopy revealed a malignant population with 40% adenocarcinoma differentiation and 50% neuroendocrine component. The neuroendocrine cells exhibited organoid and cribriform structures with rosettes-arrangements. Squamous differentiation was present. Surprisingly, the examination of the ovarian mass revealed a serous cystadenofibroma with malignant cells invading both the cystic wall and the normal ovarian stroma. Immunohistochemistry showed positivity for CK20, CDX2, Chromogranin A and Synaptophysin and negativity for CK7. The proliferation rate was 70%. All these features were consistent with a MiNEN. Conclusion: MiNEN is a rare entity and we highlight the importance of the pathological exam considering both immunohistochemistry and classic stain examination. Based on its aggressive behavior we recommend an optimal strategy of management and close supervision by a multidisciplinary team. Unexpected microscopical features and locations of metastases, as presented in this case, should always be considered as a possibility. E-PS-06-005 Columnar-lined oesophagus less than 1 cm above gastro-oesophageal junction and Barrett's oesophagus: morphological features L. Mikhaleva 1 , K. Voytkovskaya 2 , E. Fedorov 2 , A. Shidii-Zarkua 3 1 Research Institute of Human Morphology, Russia, 2 Moscow University Hospital No. 31, Russia, 3 Pirogov Russian National Research Medical University, Russia Background & Objectives: Barrett’s oesophagus (BE) is well known risk factor for oesophageal adenocarcinoma, though columnar-lined oesophagus (CLE) less than 1cm above gastro-oesophageal junction (GEJ) is not well characterised. The aim of our study was to perform a comparative morphological analyse of BE and CLE less than 1 cm above GEJ. Methods: We examined endoscopic biopsies of 60 patients: 23 with CLE less than 1cm above GEJ and 37 with BE, stained with haematoxylin-eosin. Combined PASD/Alcian Blue stain was used for detection of goblet cells (GC). Each group of patients with GS was subdivided into groups with single GS, low density GC (LDGC, count of GS 50%). Results: In patients with CLE <1 cm above GEJ cardiac-type metaplasia was found in 7 (30,43%), acid-producing metaplasia – in 4(17,39%) and intestinal – in 12 cases (52,17%): SGC – in 4 (17,39%), LDGC – in 6 (26,09%) and HDGC – in 2 patients (8,7%). Cardiac-type metaplasia was found in 4 cases of BE (10,8%), acid-producing metaplasia – in 6 (16,22%) and intestinal metaplasia – in 27 patients (72,97%): SGC in 8(21,62%), LDGC in 7(18,92%) and HDGC in 12 patients (32,43%). Conclusion: Reactive changes of epithelium presented in 34,78% CLE cases and in 56,76% BE cases. The frequency of intestinal metaplasia was 1,4-folds higher and the frequency of reactive changes was 1,6-folds higher in BE compared with CLE less than 1 cm above GEL. Reactive changes were associated with presence and density of GC. E-PS-06-006 Invasive adenocarcinoma case in the background of intracholecystic tubulopapillary neoplasia originated from adenomyoma of gallbladder T.C. Savli 1 , N. Dursun 2 , T. Bolme Savli 3 1 Istanbul Training and Research Hospital, Turkey, 2 University of Health Sciences, Istanbul Health Practice and Research Hospital, Department of Pathology, Turkey, 3 Bagcilar Training and Research Hospital, Turkey Background & Objectives: The malignant potential of adenomyomas of gallbladder has controversy. Neoplastic transformation potential in literature is reported as 3%. Intracholecystic tubulopapillary neoplasms (ICPN) are defined as preinvasive neoplasms, which form prominent protuding mass in gallbladder mucosa. There are no publications in the literature about intracholecystic tubulopapillary neoplasms originating from adenomyoma. We present our case because it has adenomyoma and intracholecystic tubulopapillary neoplasm and also invasive carcinoma foci in the same lesion. Methods: A 75-year-old male presented with abdominal pain. MRI revealed 2.1x2.1cm sized lesion with heterogeneous contrast enhancement containing suspected millimetric invasion areas at fundus of gallbladder. On PET-CT scan there was intense FDG uptake in the same area, consequently cholecystectomy was performed. Results: We encountered sized of 6.5x3x2cm polypoid lesion extending to lumen which was located at gallbladder fundus. Histopathological examination revealed a lesion within adenomyoma. This lesion protruded from superficial mucosa with a pattern similar to ICPN. There were also millimetric invasive tumour foci which was confined to adenomyoma. The tumour was extended to perimuscular connective tissue, as it was in the adenomyoma (pT2). After two year follow-up the patient had disease free survival. Conclusion: ICPN arising in an adenomyoma with invasion is a rare condition. In addition, although there was pT2 invasion in the lesion; it was confined to adenomyoma; so the expected survival will be better than other pT2 tumours. As a matter of fact, our case has been living without disease for two year. E-PS-06-007 Mixed acinar endocrine carcinoma presenting as a polyp in stomach T.C. Savli 1 , N. Dursun 2 , B. Yeni 3 , T. Bolme Savlı 4 1 Istanbul Training and Research Hospital, Turkey, 2 University of Health Sciences, Istanbul Health Practice and Research Hospital, Department of Pathology, Turkey, 3 University of Health Sciences, Department of Pathology, Turkey, 4 Bagcilar Training and Research Hospital, Turkey Background & Objectives: Although, pancreatic neoplasms can occur in any of the sites where heterotopic pancreatic tissue is present, the incidence of extra pancreatic pancreatic type neoplasms is very rare.Mixed acinar endocrine carcinoma (MAEC) is a rare clinical entity, with 30 or so cases of pancreas reported in the English literature. Methods: The patient is a 58-year-old woman who presented with epigastric pain applied to another clinic. Endoscopic investigation was done and 5x4,5x3,7 cm measured polip at the region of corpus in the stomach was seen. Polipectomy was performed succesfully. Results: This case was diagnosed as a well differantiated neuroendocrine tumour, grade 3 and than consultated to our clinic. Microscopic examination showed a malignant neoplasm with morphologic features of mixed acinar endocrine pancreatic tumour. Immumohistochemistry revealed diffuse and strong positivity with trypsin, chromogranin A and synaptophisin that consistent with exocrine and endocrine differention. There was no clinical or radiologic evidence of primary pancreatic tumour. After our diagnosis PET-CT scan was performed and there was no metastatic lymph nodes or distant metastasis. Conclusion: Heterotopic pancreatic tissue in the stomach is relatively common when we compare with another heteropias.Mixed tumours of the pancreas are extremely rare and their clinical features and pathogenesis remain unclear.Our case is originated from heterotopic pancreatic tissue in the stomach and the first case in literature.If not carefully examined, either the acinar or endocrine component may be overlooked and misdiagnosed. E-PS-06-008 A case of gastrointestinal stromal tumour, mimicking signet ring cell carcinoma A. Dobriakov 1 , K. Opalenov 1 , M. Antonov 1 , N. Shvets 1 , E. Poputchikova 1 , V. Salaeva 1 , A. Tokmakov 1 , J. Cherkasova 1 1 City Clinical Hospital of the Bahrushin Brothers, Russia Background & Objectives: Gastrointestinal stromal tumour (GIST) is the most common mesenchymal tumour originating in the digestive tract. Stomach is the most frequently affected anatomic site. Methods: A 31-year-old female was admitted to the Emergency Department with weakness, vomiting blood, and emission of dark black stools. Her hemoglobin was 8.6 g/dl. Esophagogastroduodenoscopy showed a submucosal tumour that protruded into the prepyloric antrum with a central ulcer. Wedge resection of gastric tumour was performed. The histopathology of the gastric specimen showed a firm submucosal tumour measuring 4.5x3.5 cm in size, without margin involvement. Overlying mucosa was focally ulcerated. Results: Microscopically, the tumour was seen in the submucosa and was composed of solid sheets of tumour cells with hyperchromatic nucleus and clear cytoplasm. The periphery of the tumour contained a little spindle cell component. Morphology of tumour cells had a striking resemblance to gastric adenocarcinoma with signet ring cell morphology. However, immunohistochemistry for epithelial markers (AE1/AE3, EMA, CEA) were negative. DOG-1, CD34, CD117 were positive; and Ki67-index was 3%. The tumour was diagnosed as GIST in the very low-risk category. Conclusion: We report the case of gastric GIST, mimicking gastric adenocarcinoma with signet ring cell morphology. E-PS-06-009 Distinguishing palisade veins as a histologic marker of oesophageal origin in endoscopically resected specimens J. Aida 1 , K. Takubo 1 , T. Arai 2 , T. Ishiwata 1 1 Tokyo Metropolitan Institute of Gerontology, Japan, 2 Tokyo Metropolitan Geriatric Hospital, Japan Background & Objectives: Palisade veins (PV) are considered markers of the oesophagogastric junction endoscopically. In cases of endoscopic resection, the oesophageal or gastric origin of small cancers is determined solely on histologic information. In the previous study, we revealed the PV corresponds to the intramucosal veins with a minor axis exceeding 100 μm. In the present study, we measured the lengths of PVs to allow determination of tissue origin, in various conditions such as cutting with longitudinal direction or artificial venal dilatation. Methods: We defined the intramucosal veins as reside in the proprial mucosal lamina and also lying horizontally. We measured the lengths of intramucosal veins in H&E stained specimens in totally 30 ESD specimens from each 10 of the lower oesophagus, upper or middle oesophagus, and gastric body not including the oesophagogastric junction. Results: The median lengths of intramucosal veins in the lower oesophagus, upper or middle oesophagus and gastric body were 1880 μm, 1074μm, and 848 μm, respectively. Those in the lower oesophagus were significantly longer than the others. The veins in the lower oesophagus were significantly longer than the others, and oesophageal veins were significantly longer than those in the gastric body (maximum length in the latter, 902 μm). Conclusion: In the lower oesophagus, intramucosal veins 100 μmwide or 1000 μmlong correspond to PVs. Histologically evident PVs can be used as a marker of oesophageal origin. E-PS-06-010 Adenosquamous carcinoma of gallbladder: a case report of an uncommon neoplasm I. Kourtesis 1 , A. Tsavari 1 , K. Koulia 1 , T. Vasilakaki 1 , G. Sotiropoulou 2 , K. Manoloudaki 1 1 Tzaneio General Hospital of Piraeus, Greece, 2 General Hospital of Korinthos Greece Background & Objectives: Primary gallbladder adenosquamous carcinoma (GBASC) is an uncommon neoplasm, which accounts for 0,5%-12,7% of all malignancies (in the literature, it has been represented mostly as individual case reports). Females are affected most frequently, with a male to female ratio of 1:3. It has an aggressive behavior and a poorer prognosis than adenocarcinoma. Here, we present a case of a male patient with GBASC. Methods: An 85-year-old male presented with pain in right hypochondriac region. Ultrasound and CT-scan revealed an enlarged gallbladder with thickened wall and multiple calculi occluding the lumen. Cholecystectomy was performed. Macroscopically, it was an enlarged gallbladder measuring 8x3x2cm, with a wall thickness of 0,7cm and a firm tumour measuring 1,5cm in diameter in the region of the fundus. The rest of the mucosa was of grayish tan color. Results: Microscopically, a superficially ulcerated malignant epithelial neoplasm was revealed, which comprised two main components: a) a squamous moderately differentiated and mildly keratinizing carcinoma which represented the majority (90%) of the tumour extent. The tumour invaded two thirds of the muscle wall thickness and was associated with foci of squamous metaplasia, as well as squamous dysplasia. b) a moderately differentiated intestinal type adenocarcinoma, focally invading half of the muscle wall thickness and growing on a background of high-grade biliary intraepithelial neoplasia (BilIN-3). Conclusion: GBASC is a rare, aggressive malignant tumour. Reporting this tumour adds to the literature and helps in better understanding the biological nature and pathological characteristics of this uncommon entity. E-PS-06-011 Morphological and immunohistochemical features of neuroendocrine tumours in gastroenteropancreatic tract Z. Vrekic 1 , T. Lakic 1,2 , J. Ilic Sabo 1,2 , A. Ilic 1,2 , M. Panjkovic 1 , M. Zivojinov 1,2 1 Clinical Center of Vojvodina, Novi Sad, Center for Pathology and Histology, Serbia, 2 University of Novi Sad, Faculty of Medicine, Serbia Background & Objectives: Neuroendocrine tumours (NETs) result from neoplastic proliferation of neuroendocrine cells, with both characteristics of endocrine and nerve cells. NETs can be different localizations but the most common site is the gastrointestinal including pancreas. We evaluated the morphology and frequency of NETs in our hospital as well as correlation between lymph node status and Ki67 proliferative index. Methods: Retrospectively, we analized NETs pathohistological reports of patients who underwent surgical excision of gastroenteropancreatic tumours in Clinical Center of Vojvodina in Novi Sad, in the period 2011-2018. The descriptive and correlation statistics was done. Results: It was registered 78 surgical specimens, average age of patients 58.88(±17),whereby 53.8% were male.The most frequent site was the pancreas (29.5%),followed by large intestine (26.9%).The mean tumour size was 3.71(±3.13)cm. Chromogranin A, Synaptophysin, CD56 and Ki67 were usually used immunohistochemical markers.Lymph node metastases were found in 47.44%.Positive correlation between the Ki67 index and the percentage of positive lymph nodes was determined (r = 0.343, p = 0.046 p <0.05),so tumours with higher Ki67 index gave much more lymph node deposits. Conclusion: Most NETs lymph node metastases originated from high grade tumours, with high Ki67 index. All mentioned above suggest that the proliferative index Ki67 can be used as prognostic marker for the presence of metastases, disease progression and prognosis for neuroendocrine tumours. E-PS-06-012 Demographic characteristics, histological types and complications of appendicitis operated in the clinical center of Vojvodina in 2015 Z. Vrekic 1 , T. Lakic 1,2 , A. Ilic 1,2 , A. Lovrenski 2,3 , J. Amidzic 1,2 , J. Ilic Sabo 1,2 1 Clinical Center of Vojvodina, Novi Sad, Center for Pathology and Histology, Serbia, 2 University of Novi Sad, Faculty of Medicine, Serbia, 3 Institute for Pulmonary Diseases of Vojvodina, Sremska Kamenica, Serbia Background & Objectives: Appendicitis is one of the most common surgical emmergencies of abdominal surgery. The treatment is routine procedure and includes removal of the appendix. However, appendicitis is still interesting subject for research because its etiology and pathogenesis remain unknown. The goal was to determine incidence of the most common types of appendicitis, distribution by age and gender, incidence of periappendicitis as appendicitis associated pathology and to determine perforation rate of the appendix. Methods: The analysis is carried out using documents from the Center for Pathology and Histology of Clinical Center Vojvodina. Pathohistological samples were analysed with microscope and photographed. The results were processed in Microsoft office Excel and displayed in tabular and graphical form. Results: A total of 626 cases of appendicitis from 2015 were analysed. Appendicitis affects patients from all age groups but more often occurs at a young age. It affects equally men and women. Acute forms of appendicitis occur far more frequently than chronic. The results showed that a total of 306 patients had periapendicitis (48.88%). Perforation was present in 2.72% patients. Conclusion: Appendicitis is a disease predominantly of young population. The most common form of appendicitis is acute phlegmonose appendicitis. Chronic appendicitis is more common in elderly people. Perforation of the appendix is present in a very small number of cases. E-PS-06-013 Coccidioides SPP in the cystic ganglion M. Mejia 1 , J.D. Hernandez 2 , M. Rolon 1 , M. Baldión 1 , L.E. Barrera-Herrera 1 , J. Alvarez-Figueroa 1 1 Department of Pathology and Laboratory Medicine, Hospital Universitario Fundación Santa Fe de Bogotá, Bogotá, Colombia, 2 Department of Surgery, Hospital Universitario Fundación Santa Fe de Bogotá, Bogotá, Colombia Background & Objectives: Coccidioides are soil-dwelling found in southern portions of California and southwestern United States, disseminated infection affects skin, skeletal system, and meninges. Classic spherules measure up to 250 μm in diameter and contain endospores (2-5 μm in size). Tissue response to Coccidioides is granulomatous, with and without caseation, spherules are found in macrophages and multinucleated giant cells and classicaly endospores. Methods: A 45-year-old female with a recent trip to the United States presented to emergency service with 5-hour evolution of constant, burning abdominal pain located in the epigastrium, 9/10 intensity and associated with 1 soft stool, bilateral upper limb paresthesias, asthenia and adynamia. Bile duct ultrasound revealed nonspecific diffuse thickening of the gallbladder walls, without evidence of stones inside. Cholecystectomy was performed. Results: The gallbladder presented changes due to acute and chronic cholecystitis with cholesterolosis. Cystic ganglion exposed the presence of round micotic microorganisms with presence of spherules containing endospores inside, positive with PAS, negative for gomory and mucicarmine. Coccidioides infection was recognized. Conclusion: Intraabdominal coccidioidomycosis is a very rare entity, to our knowledge, this is the first described cystic ganglion compromise due Coccidioides. E-PS-06-014 Correlation of E-Cadherin with pathological features in colorectal cancer I. Msakni 1 , R. Hedhli 2 , N. Mansouri 1 , F. Gargouri 1 , A. Saidi 1 , A. Bouziani 1 , B. Laabidi 2,3 1 Pathology Department; Military Hospital for Instruction of Tunis, Tunisia, 2 Tunis El Manar University, Medicine School of Tunis Military Hospital of Tunis, Department of Pathology, Tunisia, 3 Military Hospital of Tunis, Department of Pathology, Tunisia Background & Objectives: An important mechanism of Colorectal cancer progression is the Epithelial-mesenchymal transition. It is responsible for promoting the migratory phenotype of cancer cells through inhibition of adhesion molecules and stimulation of mesenchymal markers. The main marker is the loss of membrane E-cadherin expression. Many studies showed that colorectal cancer with low E-cadherin expression tend to have poor prognosis. Our objectives were to analyse the expression of E-cadherin in colorectal cancer and its correlation with histopathological parameters. Methods: It was a retrospective and monocentric study of 68 patients with colorectal cancer, collected at the Department of Pathology between 2011 and 2014. Results: The median age of the patients was 62 years (27-87 years). 74% of patients were males with a sex ratio of 2.9. Immunohistochemical study showed 38 E-cadherin positive and 30 E-cadherin negative tumours. The expression of E-cadherin was inversely proportional to the degree of differentiation (p = 0.001). There was no statistically significant correlation between the expression of E-cadherin and other histopathologic parameters. Conclusion: the expression of E-cadherin protein in colorectal cancer is correlated with histopathological parameters like in our study. Identification of regulators of gene expression involved in the Epithelial-mesenchymal transition process is critical for understanding tumourigenic mechanisms and therefore facilitate the development of novel therapies. E-PS-06-015 Carcinosarcoma of the ampulla of Vater: a case report S. Batur 1 , C. Turker 1 , Z.E. Kain 1 , N. Kepil 1 1 Istanbul University Cerrahpasa-Cerrahpasa Medical Faculty Department of Pathology, Turkey Background & Objectives: Carcinosarcomas are rare malignant tumours that are composed of both carcinomatous and sarcomatous elements that grow intermingled with each other. This tumour type has been detected in many different organs. However, carcinosarcoma of the ampulla of Vater is extremely rare. Methods: The patient was a 47 year-old woman, She complained of discomfort in the upper abdomen. Abdominal magnetic resonance imaging indicated nodular lesion at the head of pancreas and pancreaticoduodenectomy with lymph node dissection were performed. Macroscopically, the well-demarcated, polypoid, infiltrative tumour was identified in the ampulla of Vater. The tumour was 7x3,8x2,5cm in diameter. Results: The histological examination revealed that the tumour consisted of two components. One was an adenocarcinoma, exhibiting tubulary and cribriform architecture while the other was a sarcoma containing atypical mesenchymal cells. Immunohistochemically, the sarcomatous atypical cells were diffusely positive for vimentin, S100 and focally positive for α-smooth muscle actin; these cells are also negative for pancytokeratin and desmin. It did not contain heterologous elements. The tumour was therefore diagnosed as a carcinosarcoma. There was four lymph node metastasis. Conclusion: Carcinosarcoma of the ampulla of Vater has a poor prognosis, and lymph node metastases are often seen. We have presented an extremely rare case of carcinosarcoma of the ampulla of Vater. E-PS-06-016 Cecal mucinous adenocarcinoma with heterotopic ossification: a case report and review of the literature A. Podrimaj-Bytyqi 1 , M. Hashani 1,2 1 Faculty of Medicine, University of Pristina, Albania, 2 Institute of Pathology, University Clinical Center of Kosovo, Albania Background & Objectives: Heterotopic ossification is a very rare event in the gastrointestinal tract tumours, being less than 0.4% among them. The mechanism of ossification is still unclear. It’s usually observed in tumours associated with mucine extravasation, subsequent calcification of which it is thought to be a predisposing factor. Furthermore, osteoblastic metaplasia of cancer cells and pluripotent mesenchymal cells, both under the influence of factors generated by the cancer cells, are proposed as possible mechanisms. Methods: We present a case of a 25 years old male, who was admitted to surgical clinic with acute intestinal obstruction due to the presence of a cecal mass. The computed tomography scan and ultrasonography showed an irregular cecal mass with signs of calcification or ossification. Patient underwent surgery, where a right hemicolectomy with regional lymphadenectomy was undertaken. Results: Macroscopically, tumour was located on the upper part of the cecum, near the ileo-cecal valve, it perforated the wall and caused cecal ischemic necrosis due to the total obstruction. Tumour was exophytic, 5 cm in diameter, with hard/osseal consistency. Histologically, well differentiated mucinous adenocarcinoma with heterotopic ossification was diagnosed. In the resected specimen, six negative lymph nodes were found. Immunohistochemistry for Ki67 showed a low index of proliferation; CK20 and CEA were positive, while CK7 and p53 were negative. Conclusion: Heterotopic bone formation in colon is a rare phenomenon, especially in young patients. Colon cancer and other benign lesions of the colon which are presented with heterotopic ossification, needs to be differentiated from carcinosarcoma, which has a similar clinical presentation, but worse prognosis. E-PS-06-017 A rare soft tissue tumour of the stomach I. Dumitru 1 , M.A. Bani 1 , X. Sastre Garau 1 , T. Lons 1 1 CHI Crèteil, France Background & Objectives: Glomus tumour is a rare benign menchymal neoplasm derived from the glomus body witch is an arteriovenous anastomosis. The stomach is an exceptional site for those tumour. Their diagnosis may pose a real challenge for the pathologist especially in small gastric biopsies. Methods: A 56 –year-old man with no history referred for a microcytic anemia. The endoscopy revealed an ulcerated lesion of the greater curvature of 34 mm. The diagnostic of a stromal tumour was presumed and a biopsy performed. Histologically the tumour was composed of uniform round cells with regular nuclei and pale eosinophilic cytoplasm. Immunohistochemistry expression for smooth muscle actine and absence of staining for S100 proteine and CD117. The retained diagnosis was gastric glomus tumour. Results: Glomus tumours are rare. The first case of gastric glomus tumour was reported in 1951, since then only 34 cases have been reported in the literature. The tumour is generally benign however in one case metastasis have been reported. Malignant behaviour may be associated with the size, localization, high nuclear grade and atypia. The diagnosis can be challanging with endoscopic and radiologic findings witch are nonspecific for such tumours. Immunohistochemistry is mandatory to rule out other differential diagnoses. Conclusion: We think that the diagnosis of a glomic tumour on a biopsy is challanging. It raises a large spectrum of differential diagnoses. The pathological asses may pose the diagnosis but their prognostic factors are still to be proven. E-PS-06-019 CD44 expression in dysplastic glands of colorectal adenomas G. Cerrone 1 , V. Aimola 1 , G. Senes 1 , R. Murru 1 , G. Faa 1,2 1 Division of Pathology, Department of Medical Science, University Hospital San Giovanni di Dio, AOU Cagliari, University of Cagliari, Cagliari, Italy, 2 Temple University, Philadelphia, Pennsylvania, USA Background & Objectives: CD44 is an ubiquitous transmembrane glycoprotein that interacts with different components of the extracellular matrix. Different isoforms of CD44 exist since the mRNA encoding for this protein may undergo alternative splicing. CD44 isoforms have been related to multiple cancers, being considered stem cell markers of many tumours. CDX-2 is a fundamental regulator of intestinal development and oncogenesis, which is considered a prognostic biomarker. In this study we evaluated CD44 and CDX-2 immunohistochemical expression in polyps and adenomas of the colorectum. Methods: We evaluated 7 cases of polyps/adenomas of the colorectum. At histology 2 adenomas with high grade dysplasia (A/HGD), 4 adenomas with low grade dysplasia (A/LGD) and 1 sessile serrated polyp without dysplasia (SSPwD) were identified. Immunohistochemical evaluation for CDX-2 and CD44 was performed. Results: All cases analysed showed diffuse and intense nuclear immunoreactivity for CDX-2. All adenomas showed membrane strong and diffuse immunostaining for CD44, except for one A/LGD that revealed a focal immunoreactivity. CD44 immunostaining was mainly localized in dysplastic glands. Areas with high grade dysplasia showed stronger reactivity for CD44 than those with low grade dysplasia. Only SSPwD showed no evidence of CD44 expression. Conclusion: Our preliminary data show that the stem cell marker CD44 is expressed in colorectal adenomas. The reactivity for CD44 is stronger in high grade than in low grade dysplasia. Further studies are needed to better clarify the role of CD44 expression in colon carcinogenesis. E-PS-06-021 The value of subtyping of intestinal metaplasia for the risk stratification of gastric cancer S. Savcenko 1 , S. Isajevs 2,3 , I. Bogdanova 1,3 , I. Liepniece-Karele 1,3 , M.B. Piazuelo 4 , M. Leja 1,3 1 Institute of Clinical and Preventive Medicine; Faculty of Medicine, University of Latvia, Riga, LV-1586, Latvia, 2 Department of Pathology, University of Latvia, Faculty of Medicine, Riga, Latvia, 3 Centre of Pathology, Riga East University Hospital, Riga, Latvia, Latvia, 4 Division of Gastroenterology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, 37232, USA Background & Objectives: The use of Operative Link on Gastritis Assessment (OLGA) and Operative Link on Gastritis Assessment based on Intestinal Metaplasia (OLGIM) staging system is recommended to identify subjects at risk for developing gastric cancer, generally high-risk lesions are considered only stages III and IV. Accumulating evidence is suggesting that incomplete IM is of importance in developing gastric cancer. Our aim was to identify the prevalence of incomplete IM in patients with low-risk OLGA/OLGIM stages in a high-risk general population. Methods: Healthy adult volunteers aged 40-64 years were invited to undergo upper endoscopy within a regional GISTAR pilot study in Kazakhstan (n=166). Five gastric biopsies according to the updated Sydney system were obtained from each study subject. High iron diamine-alcian blue (HID-AB) was used for the subtyping of IM. Results: Overall 46.0% IM prevalence was revealed. Incomplete IM was present in 48.0% (type II in 22.0% and type III in 26.0%), whereas complete IM was found in 52.0% of individuals. The prevalence of OLGIM I and II stage was 85.0% and 10.0%, respectively, whereas OLGIM III was observed in 5.0%. The prevalence of incomplete IM in patients with OLGIM I was 32.0% (type II in 18.0% and type III in 14.0%). Conclusion: High prevalence of incomplete IM was revealed not only in subjects with extensive IM, but also in those stratified OLGIM I stage. Without IM subtyping, up to 32.0% of the patients with high risk of gastric cancer development would be missed for surveillance. E-PS-06-022 Gastric glomus tumour: a case report Z.E. Kain 1 , S. Batur 1 , N. Kepil 1 , O. Aydın 1 , N. Comunoglu 1 1 Istanbul University-Cerrahpasa Cerrahpasa Faculty of Medicine, Pathology Department, Turkey Background & Objectives: Glomus tumour (GT) is a rare mesenchymal tumour of stomach,arising from glomus bodies.Peripheral soft tissues and extremities are the major sites of involvement. Case series revealed that GT is 100 times rarer than gastric GIST. It is known as benign, and wedge resection with tumour-free margin is adequate for treatment. Since first case reported in 1951, there are less than 100 case reports in English literature up-to-date. Clinically and histopathologically, differential diagnosis includes gastric GIST, leiomyomas and neuroendocrine tumours. Methods: A 60-year-old female was admitted to the hospital with a pain in the left upper abdomen. A computed tomography (CT) scan of the abdomen demonstrated well-defined lesion, measuring 24x22 mm in close relation to the anterior wall of the stomach. The patient underwent laparoscopic wedge resection of the gastric mass with a preliminary diagnosis of gastrointestinal stromal tumour. Surgical resection revealed a 2x1,5x1cm well circumscribed submucosal tumour, extending into the subseroza. Results: Microscopically,the tumour showed submucosal infiltration by solid sheets of round cells having a nodular pattern of growth,separated by fibrous bands. The neoplastic cells were uniform with round nucleus,clear to eosinophilic cytoplasm,and a distinct cell border separated by dilated vascular channel lined with flat endothelium. There were no mitosis,cytomorphological atypia or necrosis. The proliferative index (Ki-67) was 1%. Immunohistochemically, the tumour cells were stained positive for alpha-smooth muscle actin, beta catenin, vimentin, collagen type IV and synaptophysin. The tumour cells were negative for CD117, CD34, pancytokeratin,HMB-45,S-100,CD56 and chromogranin. Conclusion: GT is a rare entity that clinicians and pathologists may not come across in their lifelong career. It can be easily misdiagnosed as neuroendocrine tumour and may cause pitfalls. Recent imaging techniques or endoscopic biopsy are not reliable differentiating from other mesenchymal tumours. We have presented an extremely rare case of GT of the stomach. E-PS-06-023 Leishmaniasis of duodenum: a case report G. Sotiropoulou 1 , O. Abazis 1 , C. Vasileiou 1 , E. Axioti 1 1 General Hospital of Korinthos, Greece Background & Objectives: Leishmaniasis is a disease caused by an intracellular protozoan parasite (genus Leishmania) transmitted by the bite of female phlebotomine sandfly (genus Phlebotomus). The disease is divided into 3 clinical forms: cutaneous,mucocutaneous and visceral. Visceral leishmaniasis (kala-azar) is a potentially lethal widespread systemic disease characterised by fever, weight loss, hepatosplenomegaly, darkening of the skin, pancytopenia and hypergammaglobulinemia.The prognosis is poor without special treatment(70%-90%).In Greece are recorded 30-70 cases of visceral and about 10 cases of cutaneous leishmaniasis annually. Methods: A 32 year old foreign male shepherd presented in the outpatient department with anemia. The patient also reported malaise, weakness and anorexia. CBC count demonstrated microcytic hypochromic anemia, leukopenia with decreased neutrophils and relative lymphocytosis. Prothrombin time was prolonged and biochemical studies were within normal range. US showed splenomegaly. An upper GI endoscopy was perfomed - with no essential findings - and biopsies were taken from the stomach and duodenum for the investigation of anemia. Results: Histological examination showed a dense lymphoplasmatic population with participation of neutrophil granulocytes, as well as plenty of macrophages, which in their cytoplasm contained the baseophilic Leishman Donovan bodies. The amastigotes were confirmed by Giemsa stain. Conclusion: Leishmaniasis cases are increasing in numbers favored by changing immigration conditions. The disease should be included in the differential diagnoses of various infectious parasitic disorders . Serological studies and PCR are less invasive methods for the detection of the disease.Early diagnosis , treatment and informing the population are the main measures for controlling leishmaniasis. E-PS-06-024 A unique renal cell carcinoma solitary colonic metastasis. An atypical metastatic presentation E. Koniaris 1 , I. Nikolopoulos 1 , E. Gioti 1 , K. Tsiardis 1 , E. Moula 1 , G. Kafiri 1 1 "Hippokratio" General Hospital of Athens, Greece Background & Objectives: Our aim was to present a rare and atypical metastastasis of a renal cell carcinoma(RCC), eosinophilic type, to the cecum. RCCs are tumours with strong prevalence to metastasize, virtually to all organs, but most frequently to lung, bone, brain and liver, with a 30-40% recurrence, after resection and a 10% risk of metastasis after 5 years. The gastrointestinal tract and especially the colon is a very unusual site. Methods: Our patient referred to our hospital for a regular check up, 6 months after a total nephrectomy for a RCC , a tumour mass was found endoscopically on the cecum. He underwent right colectomy and we received cecum of 20cm in length, with a protruding, ulcerated tumour m.d.: 7cm, 6cm from the ileocecal valve. Due to the previous history immunohistochemistry was performed with the following: AE1/AE3 (+), CK7 (+), CK20(-), S100 (-), LCA (-), Chromogranin (-), Synaptophysin (-), HMB45 (-), Alcian blue (-), PAS (-). Results: Histologically, the tumour was a high grade carcinoma, with mainly solid growth pattern, with tumour islands with delicated fibrovascular cores between them. The tumour cells had high nuclear atypia and pleomorphism, with presence of bizarre cells with multilobular and multinucleated forms, high mitotic index and bright eosinophilic cytoplasm. Necrosis and inflammatory elements as well as foci of abscess formation were also noted. Conclusion: The colon and particularly the cecum, is a highly uncommon site of RCC metastatic involvement. In general, this atypical presentation occurs many years after the initial kidney resection, although in our patient this occurred only a few months after the initial resection. E-PS-06-025 Nosologic structure of gastric pathology in cases of endoscopic mucosal resections M. Shushval 1 , L. Volkova 2,3 , G. Lyashenko 4 , L. Nyzhnik 4 , A. Antishina 2 , A. Musatov 2 , K. Abdujabborov 1 1 Baltic Federal University, Russia, 2 Immanuel Kant Baltic Federal University, Kalinigrad, Russia, 3 Lab. of Immunohistochemistry and Pathology Diagnostics, Russia, 4 Regional Hospital, Pathoanatomical, Kaliningrad, Russia Background & Objectives: Gastrointestinal endoscopic mucosal resection (EMR) is one of methods of diagnostics and treatment of exophytic epithelial lesions of the stomach. Our study is aimed to evaluate nosological structure and morphological peculiarities in EMR stomach specimens. Methods: The study was performed on 62 stomach samples of patients of Kaliningrad Regional Hospital after EMR during 2016-2018. Characteristics of the study group with epithelial lesions of the stomach: sex (M:F) - 10:52, age: 36-75 years. Results: Pathologic process location in the stomach: 1) body - 69.2%; 2) pylorus - 12.5%; 3) antrum - 12.1%; 4) cardia - 7.1 %. 49 cases of hyperplastic polyps with following histological appearances were revealed: 1) low grade intraepithelial neoplasia – 2; 2) intestinal metaplasia of the colonic type - 1; 3) inflammation - 6; 4) ulceration - 9; 5) cystic glandular hyperplasia – 3. Tubulovillous adenomas (9) were found: 1) 7 cases – with low grade intraepithelial neoplastic changes; 2) 2 specimens - with high grade intraepithelial lesions. Diagnosis in 1 patient - Menetrier's disease. 3 cases of malignancy were observed: 1) high grade adenocarcinoma in hyperplastic polyp - 1; 2) high grade adenocarcinoma in tubulovillous adenoma - 2. Conclusion: The predominance of benign pathology of the stomach among EMR samples was demonstrated (79.0%), but in some patients the intraepithelial neoplastic changes (14.5%) and superficial adenocarcinomas (4.8%) were found. Diagnosis of epithelial lesions of the stomach in EMR specimens is necessary for early diagnostics and effective treatment of benign processes and early stages of malignancy. E-PS-06-026 Ossified gastric tumour with tumour trombus - case report I. Guvendir 1 , K. Altundag 1 , I. Tosun 2 , I.E. Zemheri 1 , K. Ozdil 3 1 Health Sciences Health Sciences University Umraniye Eduation and Training Hospital Pathology Department, Turkey, 2 Umraniye Training and Research Hospital, Department of Pathology, Turkey, 3 Health Sciences Health Sciences University Umraniye Eduation and Training Hospital Gastroenterology Department, Turkey Background & Objectives: Glomus tumours of the stomach are very rare, mesenchymal neoplasms, account for nearly 1% of all gastrointestinal soft tissue tumours. The most common involvement of stomach is antrum. Gastric glomus tumours are submucosal tumours that lack specific clinical and endoscopic characteristics and are often mistaken for gastrointestinal stromal tumours. Methods: A 62-year-old female presented with upper gastro-intestinal bleeding for 15 years. Endoscopic ultrasound revealed a 3.5x2.7 cm-sized, round, hyperechoic mass with a central ulcer and focal calsification at the gastric wall. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) was applied. Results: Cytologic examination revealed a losely cohesive, uniform, small, round to oval cells with scant cytoplasm, indistinct cell borders and hyperchromatic nuclei with homogeneous chromatin. After that, local resection was performed. Macroscopically, 4.5x3x1.5 cm nodular mass arising submucosa and muscular layer was observed. Microscopic and immunohistochemical findings were consistent with a gastric glomus tumour with ossification and vascular tumour trombus. Mitosis was 1/50Hpf. After the diagnosis, the patient underwent systemic examination, metastasis was not found despite vascular tumour trombus. There was no evidence of recurrence 6 months after the resection. Conclusion: Gastric glomus tumour is very rare and ossified glomus have not been yet reported in English literature. We reported this case because of rarity and distinctive features. Key words Stomach, Glomus tumour; ossification, Endosonography; Biopsy, fine-needle; Cytology E-PS-06-027 Precancerous and background processes in carcinomas of the stomach M. Shushval 1 , L. Volkova 2,3 , A. Antishina 2 , L. Nyzhnik 4 , K. Abdujabborov 1 1 Baltic Federal University, Russia, 2 Immanuel Kant Baltic Federal University, Kalinigrad, Russia, 3 Lab. of Immunohistochemistry and Pathology Diagnostics, Russia, 4 Regional Hospital, Pathoanatomical, Kaliningrad, Russia Background & Objectives: Revealing of precancerous and background processes for gastric carcinomas is very important for prophylaxis and early diagnostics. The aim of the study investigation of pathological processes associated with various types of gastric carcinomas. Methods: The study group - 29 patients with arcinomas of the stomach after gastrectomy, sex (M:F) - 19:10, age: 42-75 years. Specimens from the tumours and at the different distance were investigated for evaluation of morphological peculiarities of the background and precancerous processes in the mucosa. Results: Location of gastric cancer (cases): 1) body – 14; 2) cardia – 8; 3) antrum – 4; 4) pylorus – 1. The main cancer type - adenocarcinoma ( 23 cases) of different Grade: G3 - 11; G1 - 10; G2 – 2. Precancerous and background processes in the subgroup of adenocarcinomas: 1) chronic gastritis of different activity - weak (8), moderate (7), severe (5); 2) intestinal metaplasia (17); 3) epithelial hyperplasia (13); 4) low grade (9) and high grade (3) dysplasia; 5) glandular atrophy (6). Precancerous and background processes in the subgroup of diffuse cancer (total -5): 1) chronic gastritis (5) of different activity - weak (0), moderate (4), severe (1); 2) intestinal metaplasia (2); 3) epithelial hyperplasia (2); 5) glandular atrophy (3). Mucinous adenocarcinoma (1) was revealed with association with severe active chronic gastritis and intestinal metaplasia. Conclusion: It was revealed that the main background pathology in gastric carcinomas of different types is chronic gastritis, the most common precancerous processes - intestinal metaplasia and dysplasia. E-PS-06-028 CD1a + DCs and CD83 + DCs number is associated with MSI status of CRC patients M. Gulubova 1 , K. Ivanova 1 , T. Vlaykova 2 1 Trakia University, Medical Faculty, Department of General and Clinical Pathology, Bulgaria, 2 Trakia University, Medical Faculty, Department Chemistry and Biochemistry, Bulgaria Background & Objectives: About 15% of colorectal cancers (CRC) display a deficiency in the DNA mismatch repair (MMR) system. MSI CRCs are associated with intense by lymphocyte infiltrate. Dendritic cell (DC) infiltration in CRC is investigated in CRC patients. The tumour tissue contains most S100 + and CD1a + DCs and very few numbers of all other CD types. The aim of our study is to evaluate DC numbers in CRC patients tested for MSI/MSS and to assess their significance for association with MSI and with patients’ survival. Results: MSI patients have statistically significantly greater number of CD1a + DCs in tumour stroma (TS) (p=0.001) and in the invasive front (IF) (p=0.002). In patients with stage II CRC CD1a + DCs in TS (p=0.001) and in IF (p=0.021) are statistically significant increased number. The same dependence is observed for CD83 + DCs. CRC MSI patients having increased number of CD1a + DCs both in TS (p=0.028) and IF (p=0.045) show a tendency for longer survival as compared to those with lower numbers of CD1a DCs in MSS patients. There was a tendency for longer survival of patients having increased number of CD11c + DCs in TS (p=0.106). Conclusion: CD1a + DCs number and CD83 + DCs number are associated with MSI status of CRC patients. They could be used as predictive immunohistochemical marker for MSI. This work was financially supported by the National Science Fund, Bulgaria, Research grant number KП-06-H23/2 from 17.12.2018. E-PS-06-029 Appendiceal intussusception secondary to benign lymphoid hyperplasia in appendix and cecum: report of two cases M.E. Kara 1 , E. Uzun 1 1 Gaziantep University Medical Faculty Hospital, Department of Pathology, Turkey Background & Objectives: Benign lymphoid hyperplasia in the wall of intestines is usually located in the terminal ileum and it occurs in children and young adults. Intussusception is a common cause of acute abdomen in infancy. Here we present two appendiceal intussusception cases developed due to benign lymphoid hyperplasia. Methods: Case 1: An 11-month-old baby girl was presented with discomfort, vomiting, abdominal pain and blood in feces. Abdominal ultrasonography (USG) examination revealed the appendiceal intussusception. During the operation intussusception was detected, appendix and cecum wall were found thickened. Right hemicolectomy was performed. Microscopically; there was extensive benign lymphoid hyperplasia both appendix and cecum wall. It has been verified with immunohistochemistry. Results: Case 2: A 10-month-old baby boy referred to our hospital with vomiting, abdominal pain, and blood in feces. In abdominal USG, appendiceal intussusception was detected. The patient was treated surgically. Intraoperatively, the appendix was wide and cecum wall was thickened. In additionally; small lymph nodes and thinned wall cyst were found in the mesenterium. Histological examination revealed benign lymphoid hyperplasia in appendix and cecum. The diagnosis was supported by immunohistochemically. Appendiceal intussusception is a very rare entity which has been many pathological conditions such as fecalith, foreign body, parasites, and rarely benign lymphoid hyperplasia. In the gastrointestinal tract, lymphoid hyperplasia leads to confusion, while it is induced by allergy, parasites, immunological diseases or no cause is detected. In infancy, appendiceal intussusception secondary to lymphoid hyperplasia is rare. The diagnosis is difficult preoperatively, histological examination is necessary. E-PS-06-030 Case report of a signet ring cell carcinoma of the ampulla of Vater A. Dimitriadi 1 , C. Karambogias 1 , G. Koutsonikas 2 , C. Zorzos 1 , A. Kostopoulou 1 , A. Koliopanos 3 , T. Choreftaki 1 1 Department of Surgical Pathology/General Hospital of Athens "G. Gennimatas", Greece, 2 Department of Cytology/General Hospital of Athens, "G. Gennimatas", Greece, 3 2nd Department of Surgery/General Hospital of Athens "G.Gennimatas", Greece Background & Objectives: We present a case of signet ring cell carcinoma (SRCC) of the ampulla of Vater of a 68 year old man, submitted for obstructive jaundice. Methods: Endoscopic Retrograde Cholangiopancreatography (ERCP) highlighted oedematus and brittle ampulla of Vater with constriction at the lower end of common bile duct. Biopsy was performed, positive for a primary poorly differentiated adenocarcinoma. A Whipple procedure was performed. We received a pancreatoduodenectomy. Results: A tumour was located at the ampulla of Vater with maximum diameter 1.5cm. Microscopically, the tumour consisted of, mostly, diffusely arranged, poorly differentiated cells, with signet ring cell morphology, infiltrating the duodenal wall, with lymphatic invasion and without infiltration of adjacent pancreas or peripancreatic soft tissue. Fourteen lymph nodes were identified with no metastases (pT2N0M0, according to AJCC 8th ed.). Immunohistochemical staining showed that the tumour cells were positive for CK19, CK7, MUC1, MUC5AC, and focally for CK20, MUC2, TTF1, MUC6 and negative for SYP, CgA and b-catenin. Thus, the diagnosis was a mixed type SRCC with intestinal, pancreatobiliary and gastric differentiation. Conclusion: Ampullary SRCC is an extremely rare neoplasm with only 38 cases described so far, from which only 3 were mixed type. Some studies indicate that mixed type SRCC, especially with gastric differentiation, has worse prognosis. Furthermore, coexpression of E-cadherin and b-catenin may show poorer prognosis. E-PS-06-031 Histologic description of cytopathic effects of Human Herpes Virus 6 (HHV6) enteritis S. Renne 1 , C. De Carlo 1 , T. Brambilla 1 , M. Sollai 1 , J. Mariotti 1 , E.C. Ferrara 1 , L. Di Tomaso 2,3 , M. Roncalli 2,3 , P. Spaggiari 1 1 Humanitas Clinical and Research Center - IRCCS, Italy, 2 Department of Pathology, Humanitas Clinical and Research Center - IRCCS, Rozzano (MI), Italy, 3 Department of Biomedical Sciences, Humanitas University, Rozzano (MI), Italy Background & Objectives: Patients undergoing bone marrow transplantation (BMT) often require gastrointestinal (GI) biopsies to rule out viral infections or Graft Versus Host Disease (GVHD). HHV6 is a very prevalent infection affecting 95% of the general population, and it remains latent in most of the cases, but it represents a common pathogen in immunocompromised hosts. However, a histological description of its cytopathic effect in GI tract is missing. We here provide the first histologic description of HHV6 enteritis. Methods: A 53 years-old man with a 31 years-long history of Hodgkin’s lymphoma and previous reactivation of HHV6 infection, underwent to BMT. He developed grade 3 mucositis, sepsis, diarrhea, nausea and vomiting. GI biopsies were performed to rule out GVHD: duodenum showed cytopathic alterations suggestive of viral infection; cytomegalovirus infection was excluded, and polymerase chain reaction analysis revealed the presence of HHV6 DNA. Lower-GI biopsies showed atrophy and apoptosis, compatible with GVHD. The patient was thus treated with Ganciclovir and Methylprednisolone-Etanercept. Four months later, the patient developed a severe anemia and a lethal Aspergillus pneumonia. Results: Duodenal biopsy showed atrophy and mild subacute inflammation of lamina propria; few apoptotic enterocytes were identified; epithelial and stromal cells showed marked cytomegaly and nuclear inclusions. Conclusion: To our knowledge this is the first histological description of cytopathic effects of HHV6 enteritis. Histology is of paramount importance in the management of patients undergoing BMT. HHV6 should be considered in presence of cytopathic effects and CMV negativity. E-PS-06-032 Intracholecystic papillary-tubular neoplasm (ICPN) with high grade dysplasia: a case report Y. Ozerdem 1 , B. Koca 1 , S. Kulacoglu 1 1 Ankara Numune Training and Research Hospital Department of Pathology, Turkey Background & Objectives: The histological, clinical and prognostic aspects of the neoplastic gallbladder polyps were not well-described historically. ICPN terminology is defined recently, for mass forming exophytic gallbladder lesions distinct from adjacent mucosa, measuring ≥1 cm and showing dysplasia. ICPNs are seen predominantly in women and mean age is 61. Methods: A 65-year old male with abdominal pain underwent an abdomen CT which revealed a heterogenous nodular mass in the gallbladder. Grossly a 1.4x1x1 cm green, pedinculated, friable polypoid lesion was seen at gallbladder corpus. Results: Microscopic sections showed a papillary neoplasm composed of tightly packed glandular epithelium with foci of tubulary configuration. The morphologic appearance of the glands were variable consisting of biliary epithelium, clear cells with broad cytoplasm and hyperchromatic epithelium accompanying intestinal metaplasia. High grade dysplasia is observed at %30 of the glands. Immunohistochemical staining showed the predominant cell type to be pancreatobiliary with diffuse and strong MUC1 and CK7 staining. The gastric foveolar type glands showed MUC5AC staining and the foci of intestinal differentiation were CK20 and CDX2 positive. Apart from the lesion, high grade dysplasia was also consistent in the fundus, corpus and neck extensively, with cytoplasmic pCEA staining. Conclusion: ICPNs are rare neoplasms with remarkable cell lineage diversity and biliary pattern is the most common. Although gallbladder carcinomas arise mainly from flat dysplasia, extensive evaluation is essential to exclude invasion. Reporting histopathological, immunohistochemical and clinical aspects of polypoid preinvasive gallbladder neoplasms will contribute to our knowledge about ICPNs. E-PS-06-033 Gastric adenosquamous carcinoma: A case report S. Batur 1 , R. Akpinar 1 , N. Kepil 1 1 Istanbul University Cerrahpasa-Cerrahpasa Medical Faculty Department of Pathology, Turkey Background & Objectives: Adenosquamous carcinoma, a rare malignant tumour of the stomach, is characterised by two different cell components, one adenomatous and the other squamous component. It amounts to less than one percent of all gastric carcinomas and its clinical and endoscopic findings are similar to the adenocarcinoma. It occurs more frequently in the proximal stomach and tends to be found in advanced stages at diagnosis, with a worse prognosis than adenocarcinoma. Methods: A 56-year-old male was admitted to the hospital with a pain in the left upper abdomen. An upper gastrointestinal endoscopy had revealed an extensive ulcer of the gastric antrum. The patient underwent a distal subtotal gastrectomy. Grossly specimen revealed an ulceroinfiltrative lesion occupying most of the antrum, measuring 8×5×3cm, and infiltrating his gastric wall to the serosal layer. On cutting the liver fragment, a tumour was identified as a whitish nodular subcapsular lesion of well-defined limits with a major diameter of 0.5cm. Results: A pathological exam revealed a poorly-differentiated malignant epithelial neoplasia of solid pattern and focally glandular with expansive growth. Venous, lymphatic and perineural invasion were identified. There was metastatic neoplasia in four of the ten identified lymphatic nodes, as well as in her liver fragment. Immunohistochemically, the tumour cells were stained positive for CK7, CK5-6 and p40. The tumour cells were negative for CK20, synaptophysin and chromogranin. The tumour was diagnosed as adenosquamous carcinoma. Conclusion: Primary gastric adenosquamous carcinoma is a rare malignancy. Its clinicopathologic feature and prognosis are quite different from the ordinary adenocarcinomas. We have presented an extremely rare case of adenosquamous carcinoma of the stomach. E-PS-06-034 Carcinoid tumour and Cystoisospora belli infection of the gallbladder: a case report B. Koca 1 , Y. Ozerdem 1 , S. Kulacoglu 1 1 Ankara Numune Training and Research Hospital Department of Pathology, Turkey Background & Objectives: Carcinoid tumour of the gallbladder is a rare entity comprising less than 1% of all carcinoid tumours. Cystoisospora belli , formerly known as Isospora belli is an intracellular parasite which is mostly associated with gastrointestinal disease in immunocompromised patients. Gallbladder cystoisosporiasis in immunocompetent individuals is also described. Methods: A 84 year old woman was hospitalized with nausea and abdominal pain in the right upper quadrant. She had no remarkable prior history. Abdominal ultrasound showed multiple gallstones with signs of cholecystitis and cholecystectomy was performed. 0,4 cm polypoid mass was found in the neck of the gallbladder at gross examination. Results: Histological examination revealed that the polypoid tumour was composed of small uniform cell nests with round to oval nuclei invading the mucosa extensively, and penetrating the superficial muscular layer in a small focus. No mitoses, lymphovascular and perineural invasion were seen. Tumour cells showed positive reaction for chromogranin and synaptophysin. This lesion was proved to be neuroendocrine tumour grade 1 (carcinoid) of the gallbladder. There was also an area in corpus with eosinophilic intraepithelial parasites consistent with C. belli . Intestinal metaplasia and follicular cholecystitis were also seen. Conclusion: Carcinoid tumour and cystoisosporiasis of the gallbladder are extremely rare entities. Most of the cases are incidental. To our knowledge this is the first case report of a patient with carcinoid tumour accompanying C. belli infection. Although being relatively uncommon , these two entities should be considered in the differential diagnosis of gallbladder diseases. E-PS-06-035 Spindle cell lipoma of the appendix: a rare incidental finding R. Griffiths 1 , A. Arnaout 1 1 St. George's University Hospitals NHS Foundation Trust, United Kingdom Background & Objectives: Spindle cell lipoma is a benign form of lipoma typically found in soft tissues. They show a male predominance and the majority are diagnosed between 45 to 65 years of age. Most have a characteristic distribution with up to 80% of cases arising on the posterior neck, shoulders, and back. Less frequently lesions arise intradermally or in the head and neck region, including in the oral cavity, face and orbit. Individual case reports have documented occurrences in the mediastinum, labium majus and perineum. Methods: We present a case of an 84 year old female with weight loss and anaemia. She underwent an extended right hemicolectomy for an adenocarcinoma detected on CT scan. Macroscopically an incidental 8mm firm white nodule was identified at the tip of the appendix. Results: Histological examination showed a spindle cell tumour consisting of mature adipose tissue merging with spindle cells displaying pale eosinophilic cytoplasm and uniform wavy nuclei. The spindle cells showed strong and diffuse positivity for CD34 and were negative for CD117 and DOG1. S100 highlighted mature adipocytes but was negative in the spindle cells. Histological features confirmed a spindle cell lipoma of the appendix. Conclusion: Spindle cell lipoma is a rare lipomatous tumour and to our knowledge has never before been reported in the appendix. The behaviour of spindle cell lipomas arising at unusual sites is not well known and therefore, for treatment purposes, they should be considered as similar to that of atypical lipomatous tumour. E-PS-06-036 Rapid detection of mismatch repair proteins by immunohistochemistry in colorectal cancer patients K. Kubelka-Sabit 1,2 , V. Filipovski 1,2 , B. Dimova 1 , D. Jasar 1 1 Clinical Hospital Acibadem Sistina, Department of Histopathology and Cytology, Republic of North Macedonia, 2 Medical faculty, University Goce Delchev, Republic of North Macedonia Background & Objectives: Lynch syndrome is an inherited disorder that increases the risk of many types of cancer, particularly colorectal and endometrial cancer. Therefore, all newly diagnosed colorectal cancers should be screened for Lynch syndrome. New immunohistochemistry (IHC) based tests which detect mismatch repair (MMR) proteins offer quick and reliable identification of patients with probable Lynch syndrome. Methods: In this prospective study, we evaluated 50 cases of colorectal cancer patients using the Ventana MMR IHC Panel. The panel contains five primary mouse or rabbit monoclonal antibodies: MLH-1 (M1), PMS2 (EPR3947), MSH2 (G219-1129), MSH6 (44) and BRAF V600E (VE1). The analysis was performed on automated platform Ventana Bench Mark GX, using 4μ thin tissue sections from representative tumour tissue paraffin blocks. Results: Of the 50 analysed cases, 3 cases showed absence of positivity for MLH1 and PMS2 markers. Two of these cases had MLH1 promoter hypermethylation and were classified as sporadic cancers. One case was negative for PMS2 marker and one case was negative for MSH6 marker. In total, 3 of the 50 cases analysed were sent for further Lynch syndrome testing. Two of these three patients were female and also had a history of endometrial cancer prior to the diagnosis of colorectal cancer. One case was positive for BRAF V600E antibody. Conclusion: Immunohistochemical detection of MMR proteins enables quick detection of patient with probable Lynch syndrome. Further identification of the syndrome in patients and family members may result in early detection and possible cancer prevention in these patients. E-PS-06-037 Primary extra-ampullary duodenal adenocarcinoma: a rare case report H. Seneldir 1 , G. Kir 1 , E. Apaydin Arikan 1 , T. Soylemez 1 , O. Ekinci 2 1 Istanbul Medeniyet University, Department of Pathology, Turkey, 2 Istanbul Medeniyet University General Surgery Department, Turkey Background & Objectives: Tumours arising in the non-ampullary segment of the duodenum are rare and considered true duodenal cancers. These malignant neoplasms, accounting for 0.5% of all gastrointestinal malignancies and 33–52% of small bowel adenocarcinomas. Methods: A 87-year-old male patient was admitted to our general surgery clinic with complaints of abdominal pain, nausea and vomiting. Upper gastrointestinal endoscopy was performed for diagnostic purposes. In the endoscopic imaging, a submucosal mass was observed between the 3rd and 4th segment of the duodenum causing ulceration in the mucosa. Two repetitive endoscopic biopsies showed regenerative changes in the duodenum. As the patient's complaints persisted, duodenectomy was performed. Results: Macroscopically, a 2 cm diameter tumoural lesion was found in the submucosa of the duodenum. The mucosa in this area was regular in appearance. Histologic examination revealed that the submucosal lesion was a well- moderately differentiated adenocarcinoma with clear cells. The tumour invaded the mucosa, muscularis propria and serosal fatty tissue. No dysplasia was found in the surrounding tissue. Immunohistochemistry was diffusely positive for Cam5.2, MUC-6, MUC 5AC, MUC 1, DPC4, CEA-P, negative for CK7, CK20, CDX2, MUC2, NKX2, PAX8, PSAP, SALL4, TTF-1, NAPSİN A, HMB45, TFE-3. Secondary involvement was excluded by extensive immunohistochemical panel and PET screening. Conclusion: Extra-ampullary duodenal adenocarcinomas are divided into two major subsets, intestinal type and gastric type, are associated with distinct histopathologic features and clinical behavior. Our case was evaluated as extra-ampullary duodenal adenocarcinoma originating from Brunner glands or gastric heterotopia. E-PS-06-038 CD4+ and CD8+ lymphocytes in the immune microenvironment of gastric cancer: evaluation in Tumour Tissue (TT) and Adjacent Areas of Unchanged Mucosa (AAUM) I. Mikhailov 1 , N. Danilova 1 , P. Malkov 1 , N. Oleynikova 1 1 Lomonosov Moscow State University, Russia Background & Objectives: The assessment of tumour immune microenvironment in AAUM isn’t enough studied. This is an important direction in gastric cancer research because immune cells in AAUM may contribute in epithelial-mesenchymal transition and tumour metastasis. CD4+ and CD8+ lymphocytes are the main component of antitumour immunity which controls all other cellular reactions. It is known that high density of intratumour CD4+ and CD8+ infiltration is associated with better prognosis in gastric cancer patients but it is not well known in AAUM. Methods: 55 cases of gastric cancer (surgical material) were included in our study. Lymphocytes identification was performed by immunohistochemical staining on markers CD4 (clone 4B12) and CD8 (clone C8/144B). Cell counting was performed in three fields of view (magn. x200) separately in TT and AAUM. These results were compared with classic tumour characteristics: depth of invasion (T), number of nodes metastases (N), distant metastases (M), grade (G). Results: CD4+ infiltration in TT (median=37,8 cells) was higher than in AAUM (median=19,5 cells) in samples with N3 tumours (p=0,6148); CD4+ infiltration in AAUM in samples with N3 tumours was significantly higher than in samples with N2 tumours (median=11,33). CD8+ infiltration in TT (median=105,79 cells) was higher than in AAUM (median=72,21 cells) in samples with T4a tumours (p=0,7123); CD8+ infiltration in AAUM (median=74,33 cells) in samples with T4a/T4b tumours was significantly higher than in samples with T1a/T1b tumours (median=48,33). Conclusion: High density of CD4+ and CD8+ infiltration in AAUM in gastric cancer is associated with greater depth of invasion and large number of lymph modes metastases which is opposite to intratumour infiltration. This indirectly confirms the hypothesis that CD4+ and CD8+ in AAUM may be involved in tissue restructuring that conduct to the tumour progression. E-PS-06-039 Coexistence of intrahepatic bile duct adenoma and colorectal adenocarcinoma D. Anestakis 1 , C. Tsompanidou 2 , P. Konstantinidou 1 , M.I. Givannakis 3 , I. Fountos 4 , P. Pavlidis 5 1 Department of Autopsy Histopathology, Lab. of Forensic Medicine and Toxicology, Aristotle University of Thessaloniki, Greece, 2 Department of Pathology, General Hospital of Thessaloniki "Agios Dimitrios" , Greece, 3 Surgical Department, General Hospital "AHEPA", Thessaloniki Greece, 4 Forensic Service of West Republic of North Macedonia, Kozani, Greece, 5 Lab. of Forensic Medicine, Medical School, Democritus University of Thrace, Greece Background & Objectives: Bile duct adenomas are benign proliferations of intrahepatic bile ducts usually encountered as an incidental finding. They are usually located on the surface of the liver and are <1 cm in diameter. These rare lesions should be included in the differential diagnosis of hepatic masses in addition to metastatic tumours if the patient has another malignancy. Methods: A 70 year old woman with a diagnosis of colorectal adenocarcinoma was undergoing surgery when a small nodule was discovered on the surface of the left lobe of her liver. Thought to be possible metastatic disease this lesion was excited and sent for pathologic evaluation. The diagnosis of this nodule was benign in frozen sections intraoperatively and colectomy was performed during the same operation. Results: Macroscopically the nodule of the liver was well circumscribed but not encapsulated, gray-white nodule measuring 1 cm in diameter. The microscopic study of the lesion showed an increased number of small, normal appearing bile ducts lined with a single layer of cuboidal cells which were positive to cytokeratin 7, negative to cytokeratin 20 and had a ki67 proliferation index of 1%. The morphology, immunophenotype and ki67 proliferation rate were consistent with a bile duct adenoma. The tumour of the colon was a pTNM stage II adenocarcinoma. Conclusion: Recognition of this unusual co-existence of tumours could help to elaborate the appropriate therapeutic strategy for these patients. E-PS-06-040 A rare case of acute abdomen in a pregnant woman – deciduosis of the appendix F. Galante Pereira 1 , A. M. G. Pereira 1 , C. A. Padrão 1 , J. Palla Garcia 1 , R. S. S. Oliveira 1 1 Hospital Prof. Doutor Fernando Fonseca, EPE, Portugal Background & Objectives: Ectopic decidua reaction or deciduosis is a physiological phenomenon that results from the effects of progesterone on extrauterine mesenchymal cells during pregnancy. In rare cases, ectopic decidual tissues can develop in the appendix. This case report pretends to raise the awareness of this uncommon finding. Methods: A 30-year-old primigravida in her 17st week of an uncomplicated pregnancy, presented with nausea, right lower abdominal pain, positive Blumberg sign, slightly increased inflammatory markers, and a positive ultrasound for acute appendicitis. Following the diagnosis of appendicitis, the patient was later submitted to an appendicectomy. Hematoxylin-eosin, vimentin, calretinin and AE1/AE3 stain were performed. Results: On specimen handling, there were white plaques and small nodules on the serosa. Histologically, the lesion was composed by haphazardly distributed sub-mesothelial decidualized cells, occasionally forming nodules. The vimentin was positive and the vimentin, calretinin and AE1/AE3 stain were negative. Conclusion: It is important to be aware of less frequent causes of acute abdomen in a pregnant woman. All these diseases can present with similar clinical and imagiologic findings, highlighting the role of the pathologist in the final diagnosis. E-PS-06-041 Evaluation of reproducibility of the diagnosis of gastric intraepithelial neoplasia/dysplasia: possibility of using mathod as a part of continuous professional education for pathology S. Mozgovoi 1 , A. Kononov 1 , A. Shimanskaya 1 , M. Parygina 1 , M. Keruchenko 1 1 Omsk State Medical University, Russia Background & Objectives: There is a need to introduce optimally reproducible classification approaches into the practical activity through the system of continuous education. The purpose of this study was to assess the level of consistency of the pathology diagnosis of gastric intraepithelial neoplasia / dysplasia on the consensus model. Methods: A collection of 45 histological slides from the material of gastrobiopsy was compiled. All diagnostic categories of the Modified Vienna classification of gastrointestinal neoplasia were showed on these data. Histological slades were stained with hematoxylin and eosin and then were photographed to obtain 216 representative images.Only the unambiguously evaluated cases were included (26 cases corresponding to 98 images). An analysis of the agreeement of the diagnostic evaluation was performed by peer review using the Cohen's kappa. Results: The kappa level ranged from 0.2 (poor agreement, unweighted kappa) to 0.47 (average level of agreement, linear weighted) and 0.66 (good agreement, quadratic weighted ). A simplified assessment method was used to record individual expert opinion in the binary evaluation format in regard to neoplasia/dysplasia diagnosis (yes/no). The application of this approach led to 0.47 unweighted kappa, which corresponds to average level of agreement. Conclusion: The analysis showed average degree of agreement. The difficulties of introducing modern definitions of intraepithelial neoplasia/dysplasia such as a large number of diagnostic categories, an insufficient level of agreement in evaluating the signs of intraepithelial neoplasia/dysplasia, the lack of full follow-up to recommendations were identified. E-PS-06-043 Cystic lymphangioma of the sigmoid colon: a case report A. Jurescu 1 , A. Dema 1,2 , S. Tăban 1,2 , M. Cornianu 1,2 , A. Mureșan 1,2 , C. Lăzureanu 1,2 , R. Cornea 1,2 1 Department of Pathology, "Victor Babeș" University of Medicine and Pharmacy, Timișoara, Romania, 2 Department of Pathology, Emergency County Hospital Timișoara, Romania Background & Objectives: Lymphangiomas are considered benign malformations of the lymphatic system but still, their pathogenesis is poorly understood. They are occasionally found in the abdomen, being generally cystic in type in this area. Colon cystic lymphangiomas are infrequently, the sigmoid segment being the least common location. At the same time, they are very rare in adulthood only a few cases being reported in the elderly. They usually are incidentally detected on colonoscopy or in colonic resection for other pathology. Methods: We report the case of a 62 years old male, admitted in the outpatient clinic of County Hospital with hemorrhoidal disease and rectoragy. A colonoscopy examination was performed which showed multiple sigmoidal polyps. For this reason, he was referred to the Surgery Department for surgical intervention. A sigmoid segmentary colectomy was performed and sent to the Pathology Department. Results: Grossly, a 5 cm soft polypoid lesion was identified, with a smooth surface, on cross-section having a multicystic appearance and clear fluid content. Histologically, a submucosal multilocular cystic lesion was observed, with overlying normal colonic mucosa. The cystic spaces, separated by variable thickness fibrous septa, were lined by a single layer of endothelial cells, positive immunohistochemically for D2-40. Focally we observed a cuboidal cell and giant multinucleated cells lining, positive for CD68 marker. Conclusion: We present a unique case found in our Department. The particularity of the case consists of the fact that colon cystic lymphangiomas are extremely rarely found in the elderly, especially in the sigmoid colonic segment. Also, to our knowledge, this is the second study to describe the histiocytic replacement of endothelial lining as a sign of spontaneous resolution. E-PS-06-044 Hepatoid adenocarcinoma of the colon: a case report and literature review S.A. Postolache 1 , M. Svrcek 1 , Y. Parc 2 , R. Cohen 3 1 Department of Pathology, Saint-Antoine Hospital, Paris, France, 2 APHP Sorbonne Universitè, France, 3 Department of Oncology, Saint Antoine Hospital, Paris, France Background & Objectives: Hepatoid adenocarcinoma (HA) is a rare and highly aggressive tumour, firstly described in the stomach, morphologically characterised by hepatocellular and adenomatous differentiation. HA can occur in other organs including the colon, where less than 20 cases have been reported. Methods: We present the case of a 49-year-old female patient taken into medical care for rectal bleeding. The colonoscopy revealed a sigmoid tumour for which biopsies confirmed a poorly differentiated adenocarcinoma. A CT scan excluded any distant lesion and the patient underwent sigmoidectomy with lymph node resection. Results: Pathological examination revealed cuboidal atypical cells with eosinophilic cytoplasm, arranged in a solid or trabecular fashion, resembling that of HA. The tumour cells were positive for hepatocellular markers (alpha-fetoprotein, HepPar-1, Glypican 3 and Arginase) and also for gastro-intestinal origin marker (CDX-2). The tumour was finally staged pT3N1b (2 positive lymph nodes, including the pedicular lymph node) with a mismatch repair proficient status. The patient was treated with a cytotoxic regimen of FOLFOX (oxaliplatin, leucovorin, 5-fluorouracil) during 3 months, with stable results being achieved after 5 months. Conclusion: The HA is a rare type of primary colon cancer, that carries a very poor prognosis. It is essential to exclude a primary hepatocellular carcinoma. Because little is known about the pathogenesis of this unusual tumour, further studies are needed to identify a potentially guided standardised management. E-PS-06-045 Analysis of gastrointestinal (GI) tract pathology frozen sections (FS) in tertiary referral cancer hospital in India: an audit of 3 years (1/1/2016 to 31/12/2018) K. Deodhar 1 , A. Jadhav 2 , R. Kumar 2 , M. Bal 2 , M. Ramadwar 2 1 European Society of Pathology, International Academy of Pathology-Indian Division, India, 2 Department of Pathology, Tata Memorial Hospital, Mumbai, Homi Bhabha National University, India Background & Objectives: We aimed to analyse the distribution, sensitivity, specificity, positive and negative predictive values of frozen sections in GI pathology in our institution for a period of 3 years. Methods: Between 1 st Jan 2016 to 31 st Dec 2018, 1704 frozen sections (FS) were carried out in gastrointestinal oncosurgery, out of overall total 14740 FS; constituting 11.6% of total workload. The frozen section diagnoses and their paraffin section diagnoses are noted from the records. Results: Cholecystectomy specimen for primary diagnosis and common bile duct cut margin (402 cases;23.6%) was the commonest FS; followed by gastrectomy margins (318cases;18.66%), followed by margins of colorectal resection specimen(300cases,17.60%). Other FS requests included Whipple surgery for margin, peritoneal nodule biopsy, liver biopsy, lymph node biopsy etc. (constituting approximately 684cases;40.14%). However, if all organ surgeries are considered, (colorectal, stomach, pancreas, extrahepatic bile duct excision), margin assessment was the most frequent ( 41.8%) FS request (713 out of 1704). The accuracy of FS when compared with paraffin report was 96.77% (35 discordant cases out of total 1704 cases; 91.71% sensitivity, 99.69% specificity, positive predictive value of 98.84%, negative predictive value of 97.68%). Commonest discrepancies were in peritoneal biopsy interpretation and primary diagnosis of gall bladder. The reasons for discrepancies included superficially cut tissue, scanty tissue, sampling error and interpretation error due to freezing and crushing artefacts. Conclusion: Cholecystectomy for primary diagnosis and cut margins are the commonest FS requests in GI pathology. We can attempt to avoid discrepancies by studying deep cuts, careful sampling and being cautious of the artefacts. E-PS-06-046 Comparison of clinicopathological and molecular features between left-sided and right-sided colon adenocarcinoma E. Cakir 1 , D. Unal Kocabey 1 , N. Ekinci 2 , A. Avci 2 , A. Akder Sari 2 1 Izmir Katip Celebi University Ataturk Training and Research Hospital Department of Pathology, Turkey, 2 Izmir Katip Celebi University Ataturk Training and Research Hospital Department of Pathology Izmir Turkey Background & Objectives: Colon cancer is among the leading causes of cancer-related deaths all over the world. Recent data suggest that right-sided colon cancer (RSCC) and left-sided colon cancer (LSCC) have different clinicopathological and biological features and should be considered as two distinct disease entities. This study aimed to compare the clinicopathological parameters and molecular features between right and left-sided colon adenocarcinomas. Methods: We reviewed resected colon adenocarcinoma cases from our institutional database; 40 cases of right-sided (cecum, ascending colon, hepatic flexure, transvers colon) and 54 cases of left-sided (splenic flexure, descending colon, sigmoid colon). Parameters including age, gender, histological grade, tumour size, pT stage, pN stage, lymphovascular invasion, perineural invasion, presence of tumour deposit, mutations of KRAS and NRAS were analysed. Results: The patients with RSCC were older and their tumour size were larger than LSCC but the differences were not statistically significant. KRAS and NRAS mutations were identified respectively in 43.6 % and 16% of RSCC compared with 25.9 % and 7.5% of LSCC (P=0.118 and p=0.415). Right-sided colon cancers more frequently displayed higher histological grade (27% vs 14.9%) compared with LSCC (p=0.185). There was no statistically significant differences between RSCC and LSCC according to gender, lymphovascular ainvasion, perineural invasion, pT stage, pN stage and presence of tumour deposit. Conclusion: Right-sided colon adenocarcinomas tend to show relatively larger tumour size, frequent KRAS and NRAS mutation and higher histological grade when compared with left sided colon adenocarcinomas. E-PS-06-047 A rare case of synchronous double cancer in the oesophagus and stomach C. Ciora 1 , M. Cornianu 2 , S. Taban 3,4 , G. Oprisan 1 , M. Iacob 5 , A. Ghiughici 6 1 Department of Pathology, University of Medicine and Pharmacy "Victor Babes", Timisoara, Romania, 2 V. Babes University of Medicine and Pharmacy, Romania, 3 Emergency Clinical County Hospital ''Pius Brinzeu'' Timisoara, Romania, 4 ''Victor Babes'' University of Medicine and Pharmacy Timisoara, Department of Pathology, Romania, 5 Department of Pathology, Emergency County Hospital Timișoara, Romania, 6 Department of Gastroenterology and Hepatology, University of Medicine and Pharmacy "Victor Babes", Timisoara, Romania Background & Objectives: Squamous cell carcinoma of the oesophagus is occasionally associated with other malignancies, particularly of the respiratory tract and the head and neck. Presentation of synchronous diffuse gastric carcinoma is rare but important to be investigated, because stomach is the main organ used for reconstruction of the alimentary tract after esophagectomies. In cases where there are synchronous gastric tumours, the colon becomes an option for transit reconstruction. Methods: A 66-year-old man, with a medical history of accidental caustic ingestion, had presented with appetite loss, dysphagia, epigastric pain and reflux symptoms for several months. Results: Oesophagogastroscopy showed an oesophageal stenosis and a mucosal edema of the gastric angle. Abdominal and thoracic CT scan with contrast showed strong and regularly thickness in the middle third of the oesophagus due to an oesophageal stenosis longer than 6 cm. The oesophagus and gastric biopsy revealed an invasive non-keratinized squamous cell carcinoma of the oesophagus (nuclear expression for p63) and a diffuse gastric carcinoma - signet-ring cell carcinoma (tumoural cells positive for pancytokeratin, AE1/AE3 and mucin stain - PAS-AA). Conclusion: During the initial study, physicians should consider the possibility of a double cancer. Therefore, reporting such cases in the future, will increase our knowledge to avoid misdiagnosis and delayed therapy for the double cancer cases. E-PS-06-048 Adenosquamous carcinoma of perianal region: an unusual site of occurence G. Sahraoui 1 , L. Bouzidi 1 , L. Charfi 1 , R. Doghri 1 , K. Mrad 1 , M. Driss 1 1 Salah Azaiez Institute, Tunisia Background & Objectives: Perianal carcinoma is rare accounting for less than 2% of all gastrointestinal malignancies. It may arise de novo or from a fistula or abscess cavity. This is an aggressive cancer often misdiagnosed clinically as benign pathology. We report a case of perianal adenosquamous carcinoma to highlight its epidemiologic, clinical and pathological features. Methods: A 53-year-old woman with no chronic history of perianal fistulas or abscesses was referred to our hospital for management of melena with alternating diarrhea and constipation. Results: Clinical examination and particularly digital rectal examination was normal. Colonoscopy did not reveal a rectal or colic tumour. The pelvic enhanced magnetic resonance imaging revealed perianal infiltrating tumour. Histopathological evaluation of abdominoperineal resection revealed an adenosquamos carcinoma arising from perianal glands. The continuity between the anal gland epithelium and the tumour was evident. Lymphovascular and perineural invasion was frequent. Surgical margins were tumourous. The absence of associated abscess or fistula was microscopically confirmed. Tumour was positive for CK7 and negative for CK20. Conclusion: Carcinoma of the perianal region is an oncologic rarity posing a diagnostic and therapeutic dilemma due to very few reported cases without definite therapeutic guidelines. E-PS-06-049 Colorectal cancer: age dynamics of tumour volume A. Filin 1 , A. Sizov 1 , V. Danilenko 1 1 Voronezh State Medical University named after N.N. Burdenko, Department of Pathological Anatomy, Voronezh, Russia Background & Objectives: Despite the improvement of early diagnosis methods, late-stage colorectal cancer is diagnosed in more than 25% of patients, and tumours of stage I–II are detected in less than half of patients. The aim of the study was to analyse the dynamics of tumour volume in patients of different age groups. Methods: 527 patients (238 men, 289 women, average age was 64,7 years old) suffering from colorectal cancer, underwent primary resection of the tumour. Based on the data obtained from the description of the removed intestinal fragments, the tumour volume was calculated. Results: Volume of the tumour varied considerably from 0,1 cm 3 to 1650 cm 3 (the average volume was 37,3 cm 3 ). The largest tumours were found in the youngest patients (up to 40 years). In all the studied age periods the incidence of different volume tumours was similar. Most often, in every 5 cases (on average 21.5%) in all age groups there are tumours with a volume of 16-32 cm 3 . Tumours with smaller volumes are less common, with approximately the same pattern. The largest and smallest tumours are less common, in 3.5% and 4.6% of cases, respectively. It can be assumed that tumours with a small volume are not common because of their rapid progression, and after reaching a certain volume (16-32 cm 3 , the diameter of such foci varies within 2.5-3.5 cm), their growth is significantly inhibited and only in a few cases the tumours grow to giant sizes. Conclusion: The change in tumour volume in colorectal cancer is nonlinear, which can explain the low rates of detection of the tumour in the early stages. E-PS-06-050 Digestive lymphomas G. Sahraoui 1 , N. Redissi 1 , R. Doghri 1 , L. Charfi 1 , K. Mrad 1 , M. Driss 1 1 Salah Azaiez Institute, Tunisia Background & Objectives: Gastrointestinal tract is the most common extra nodal site of lymphomas accounting for 5%-20% of all cases with a majority of non-Hodgkin type. The most frequent sites are the stomach followed by small intestine and ileocecal region. Almost 90% of these lymphomas are of B cell lineage. Our aim was to report clinical and histopathological features of digestive lymphomas. Methods: We identified cases of digestive lymphomas between January 1999 and December 2018. Results: Our series included 143 cases of digestive lymphomas. The sex ratio was 2.3. The average age was 55 years (3-84 years). The most frequent location was gastroduodenal (86%) followed by rectocolic location (10%). Concomitant gastric and colonic localization was found in 2% of cases. Ileal site was noted in 1% of cases and anal site in 1% of cases. Marginal-zone lymphoma was diagnosed in 56 % of cases, large cell B lymphoma in 39% of cases and Burkitt Lymphoma in 3% of cases. Two per cent of cases were difficult typing. Evolution was marked by a transformation of MALT lymphoma into large cell lymphoma in two cases and recurrence in 21 cases. Conclusion: There has been a tremendous leap in the diagnosis, staging and management of these lymphomas attributed to a better insight into molecular aspect and the knowledge about its critical signaling pathways. E-PS-06-051 Somatostatin-producing neuroendocrine tumours of the duodenum: clinical aspects, histological features and immunohistochemical profile - two case reports A. Cohn 1 , G. Terinte-Balcan 1 , M. Manuc 2 , V. Enache 3 , C. Iosif 3 , G. Becheanu 3 1 Emergency University Hospital, Bucharest, Romania, 2 Fundeni Clinical Institute, Bucharest, Romania, 3 Victor Babes National Institute of Pathology, Bucharest, Romania Background & Objectives: Somatostatinoma is a rare neuroendocrine tumour, derived from the delta-cells of the pancreas or the endocrine cells of the digestive tract. We report two cases of sporadic well-differentiated duodenal somatostatinoma, one of them with pancreatic invasion and multiple hepatic metastases, diagnosed at Victor Babes National Institute of Pathology. Methods: We present two somatostatin-producing endocrine tumours of a 42-year-old male and a 50-year-old female, which were evaluated according to location, morphology and immunohistochemical profile. Stains for synaptophysin, chromogranin, somatostatin, Ki-67 and SSTR2 were performed. Results: The female patient underwent upper endoscopy for abdominal pain, which evidentiated a duodenal ulcerated lesion with infiltrative pattern. Imagistic exams revealed a tumoural mass of 47/37/32 mm situated near the ampullary region, invading the head of the pancreas, hepatic metastases and lymph node enlargement. tumoural markers CA 125, CA 15-3 and CA 19-9 were increased. Two months later, the patient started chemotherapy. There was no evidence of neurofibromatosis type I. No clinical data were available for the male patient. Microscopically, the tumours exhibited tubular and glandular architectural pattern, with focal islets and trabeculae. One case presented psammoma bodies in glandular spaces. Tumours were positive for synaptophysin, chromogranin and somatostatin and presented a low Ki-67 index (<10%). SSTR2 reaction was negative. Conclusion: Given the low incidence of this tumour, its malignant potential and the differential diagnosis with adenocarcinoma, somatostatinoma represents a clinical and morphopathological challenge. tumoural size may predict the rate of metastasis, but a correlation between a low Ki-67 index and extensive metastases must be further investigated. E-PS-06-052 A single center experience in subepithelial oesophageal lesions (2000-2018) T. Cardoso Lima da Costa Pereira 1 , D. Pereira de Melo 1 , J. Magalhães 1 1 Centro Hospitalar Universitário de São João, Portugal Background & Objectives: Subepithelial oesophageal lesions (SELs) are frequently clinically assymptomatic and the vast majority are incidental findings. The differential diagnosis includes a number of benign and malignant nonepithelial tumours. Methods: All cases with diagnosis of SELs registered in our center, from 2000 until 2018, were collected for review, and six variables were chosen for analysis: age, gender, type of surgical specimen , type of SEL, concomitant lesion and follow-up. Results: Sixty-four cases were reviewed, fifty-eight of which were from female patients. The mean age at the time if diagnosis was 52,77 years. The majority had no concomitant lesion (n=51) and had been clinically discharged during follow-up (n=41). Leiomyoma (n=37), followed by granular cell tumour (n=10) and GIST (n=6) were the most common findings and biopsy (n=30) was the most common type of surgical specimen. Conclusion: An eighteen-year review at our center demonstrated that most SELs occurred in female patients and had no associated lesions. Leiomyoma was the most frequent lesion, wich is compatible with the data described in the literature. E-PS-06-053 The effect of pathological changes in the intestinal wall on the translocation of microorganisms in rats with strangulation intestinal obstruction M. Tusupbekova 1 , D. Amanova 1 , P. Ivachyov 1 , A. Lavrinenko 1 , Y. Turgunov 1 1 Karaganda Medical University, Kazakhstan Background & Objectives: The aim is studying the effect of histological changes in intestinal wall on the microbial translocation in strangulated intestinal obstruction (SIO). Methods: 30 male rats were divided into 3 groups: I (BT+) - 12 rats with SIO model and present bacterial translocation, II (BT-) – 12 rats with model SIO and absence of translocation, III- 6 rats of the sham group (laparotomy without model). The SIO model was created under general anesthesia by clipping the loop of small intestine and feeding mesentery for 60 min with a further reperfusion for 2 hours. Translocation detection was carried out after injection of suspension of fluorescent E. coli with further microbiological examination of homogenized organs. Morphological study of intestine and mesentery was performed by the “Leica DM 1000” microscope. The significance of differences was determined by Fisher's exact test. Results: In 10(83.3%) cases of BT+ group histologically in the intestinal wall was observed desquamation and necrosis foci in all layers of the intestine up to muscular, vascularization of mesentery, perivascular lymphocytic infiltration, in 2 (16,65%) the process is also organic with a submucosal layer with point foci of necrosis of the muscular layer. In the BT- group morphological picture in 11(91.6%) is represented by damage to the layers of intestinal wall to submucosal and intact muscular layer, edema of mesentery. Morphologically changes were not found in the sham group. Conclusion: Thus, the fact of the BT is associated with the depth of defeat of intestinal wall, the presence of muscle necrosis leads to bacterial translocation (p<0.05). Supported by Grant Ministry of Education and Science Republic of Kazakhstan E-PS-06-054 Long term survivor of ampullary undifferentiated carcinoma with osteoclast like giant cells S. Giusca 1 , I.D. Caruntu 1 , D. Ciobanu 1 , A.D. Timofte 1 , A. Rusu 1 1 "Grigore T. Popa" University of Medicine and Pharmacy Iasi, Romania Background & Objectives: Undifferentiated carcinoma with osteoclast-like giant cell (UCOGC) is a rare heterogeneous tumour defined by the presence of two populations, the mononuclear pleomorphic tumour cells and non-tumour multinucleated giant cells (MGC), with a recently accepted good prognosis. It was described in numerous organs, more frequently in pancreas; few cases located in Vater ampulla are reported. Methods: We report a case of a 45 years old male patient, admitted for jaundice in a surgical department in February 2009. Abdominal ultrasound revealed a solid mass and dilated distal common bile duct leading to periampullary tumour suspicion. Subsequently, Whipple procedure was performed by surgeons. Results: Gross examination of the pancreatoduodenectomy specimen revealed a focally ulcerated intestinal mucosa and a solid, white tumour of 2 cm diameter, involving the ampullary area, duodenal wall and adjacent pancreas. Histopathological exam showed an epithelial proliferation composed from individual pleomorphic spindle or round-ovoid cells forming trabeculae or discrete duct-like structures chaperoned by scattered MGC with benign appearance, mainly located intraampullary with limited pancreatic invasion (<0.5 cm). Immunohistochemically, the pleomorphic tumoural cells were positive for CK AE1/AE3 and Vimentin; MGC cells were positive for CD68 and Vimentin, and negative for CK AE1/AE3; immunostaining for LCA, CK7, CK20, and CDX2 was negative. The final diagnosis was ampullary UCOGC, stage III A. The patient had a good clinical course with no metastasis or local recurrence till July 2017, qualifying as a very long term survivor. Conclusion: Our case report confirms the good clinical course of ampullary UCOGC, and completes the limited data available on this entity. E-PS-06-056 Liver metastases of gastrointestinal stromal tumour (GIST): a case report and literature review V. Caamaño 1 , E. Camacho 1 , R. Ruiz 1 , B. Atares 1 , I. Saenz de Santamaria 1 , J. Aguirrre 1 , A. Perez 1 , I. Gorostiaga 1 , A. Martinez 1 , N. Barriobero 1 , L. Lorente 1 1 Araba University Hospital, Spain Background & Objectives: Gastrointestinal stromal tumour is the most frequent mesenchymal tumour in the gastrointestinal tract, accounting for 1% to 3% of all gastrointestinal neoplasms following gastric and colorectal cancer. Methods: 72 years old woman with a history of abdominal discomfort for and weight loss over the last two months. Physical exam showed abdominal pain at abdominal palpation. The resonance magnetic images (MRI) demonstrated a 13cm mass on the stomach and also 0,7cm on the liver. A fine needle aspiration biopsy of the gastric mass was performed and it was diagnosed as: Gastrointestinal stromal tumour (GIST). Results: The patient underwent surgery of the gastric and liver masses. Pathology report showed in both lesions: A proliferation of monotonous spindle cells arranged in fascicles. Immunohistochemistry showed positivity for: DOG1, CD117 and CD34 and negativity for: SMA, S100 and desmin; Ki67: 10%. The final Diagnoses was: Gastrointestinal stromal tumour of the stomach (13cm) with liver metastases. Conclusion: Approximately 40% to 50% of gastrointestinal stromal tumour (GIST) patients will have recurrence or metastases after surgical removal of the primary lesion. The most common affected sites are liver and peritoneum.Imatinib has been propose as the first line therapy for metastatic GIST, however surgery for metastases should be considered when is possible. The long –term outcome of GIST patients with liver metastases remain unknown. E-PS-06-057 High grade appendiceal mucinous neoplasm M. Chantziara 1 , X. Grammatoglou 1 , S. Pappa 2 , D. Mpouklas 1 , A. Kostopoulou 1 , E. Gettimis 3 , T. Choreftaki 1 1 Department of Surgical Pathology/General Hospital of Athens, "G.Gennimatas", Greece, 2 Department of Cytology/General Hospital of Athens, "G.Gennimatas", Greece, 3 1st Department of Surgery/General Hospital of Athens, "G.Gennimatas", Greece Background & Objectives: We present the case of a 63-year-old male patient with high grade appendiceal mucinous neoplasm. Methods: The patient presented to the emergency department complaining of severe pain on his right lower quadrate (RLQ) of the abdomen with duration of 12 hours. Standard laboratory examination showed mild leukocytosis. The radiological examinations revealed a dilated appendix. The patient underwent appendectomy. Results: Microscopic examination revealed replacement, focally, of the normal appendiceal epithelium by mucin-producing columnar epithelium with low or high grade dysplasia in a micropapillary or cricriform growth pattern, loss of lamina propria and muscularis mucosae with submucosal fibrosis and pushing invasion into the muscularis propria. Τhe remnant epithelium was ulcerative. Pools of acellular mucin were found into the muscularis propria and mesoappendix. Conclusion: High-grade appendiceal neoplasms (HAMNs) are rare tumours that resemble LAMN in lacking destructive invasion, but show high-grade cytologic features. This term has been recommended in a recent consensus publication and has been included in the AJCC 8th edition. E-PS-06-058 HER2 status in paired of gastric biopsies and resection specimens: is biobsy reliable for prediction of HER2? M.E. Kara 1 , E. Uzun 1 1 Gaziantep University Medical Faculty Hospital, Department of Pathology, Turkey Background & Objectives: In breast and stomach cancer, HER2 oncoprotein overexpression is very important for prognosis and treatment. HER2 protein overexpression is thought to increase that proliferation activity and suppress apoptosis of the malign cells. Therefore Trastuzumab/HER2 treatment is a choice for patients with advanced stage/metastatic gastric cancer. Since these patients are usually inoperable at diagnosis, it is important to accurately and reliably determine HER2 status. For HER2 analysis, sometimes the only available material can be small biopsies. The aim of this study is to determine the reliability of HER staining applied to biopsy materials for the decision of HER2 treatment in patients with gastric cancer. Methods: HER2 status in paired of 35 gastric biopsy and resection materials were examined. The HER2 stained cases were confirmed by silver in situ hybridization (SISH). The result of resection specimens was considered as a gold standard. Results: The concordance of HER2 status between biopsy and gastrectomy materials was 91%. In biopsy materials, there was no false positive case, while three cases showed false negativity. The positive predictive value of biopsy material was 100% and the negative predictive value was 91.8% in determining HER2 status. Conclusion: In determining the HER2 status, the biopsy materials provide accurate and reliable data. In discordant cases, the tumour heterogeneity is accepted as the main cause. E-PS-06-059 Prevalence of oesophageal squamous papillomas (ESPs) in Romania: a 12 year multicentric retrospective study A. Evsei 1 , C. Rosianu 1 , N. Copca 1 , C. Gheorghe 2 , M. Diculescu 2 , M. Dumbrava 2 , B. Codruta 2 , I. Bancila 2 , V. Herlea 2 , V. Enache 3 , S. Enache 3 , F. Vasilescu 3 , F. Andrei 3 , A. Birceanu 4 , C. Iosif 4 , A. Dumitru 5 , M. Sajin 5 , G. Becheanu 3 1 CESITO Center, Saint Mary Clinical Hospital, Bucharest, Romania, 2 Gastroenterology and Hepatology Center, Fundeni Clinical Institute, Bucharest, Romania, 3 Victor Babes National Institute, Bucharest, Romania, 4 Pathology Department, Saint Mary Clinical Hospital, Bucharest, Romania, 5 Pathology Department, Emergency University Hospital, Bucharest, Romania Background & Objectives: Oesophageal squamous papillomas (ESPs) are rare epithelial tumours with an uncertain etiology and a variable reported incidence. Chemical, mechanical and viral agents have been proposed as a mechanism of pathogenesis with recent reports arguing in favor of malignant transformations, but so far there is little information on a direct cause for this lesion. Methods: We reviewed all patients who underwent an upper gastrointestinal endoscopy as part of a multicentric retrospective study which comprised four clinical and research institutions. We collected a total of 123 cases of microscopically confirmed ESPs over a period of 12 years (2006-2018). Our purpose was to establish a more precise incidence of this lesion in Romania and to find evidence for a possible link to tumour progression. Results: According to our data, clinical and pathological diagnosis of ESP was highest in 2013 (18,69%) in all four centers. Female patients were more affected than male patients with a 1,3:1 sex ratio. More than 90% of lesions were under 5 mm and the age category most often affected was between 26 and 50 years old. 88% of cases were single lesions and their typical location was found in the distal third of the oesophagus (71 cases). 20,32% cases associated lesions in other locations such as Helicobacter pylori associated chronic gastritis, reactive gastritis, gastric hyperplastic polyps etc. Conclusion: ESPs are unusual, frequently benign lesion that are still under debate regarding their mechanism of pathogenesis. Despite their rarity, their potential for malignant transformation warrants an attentive approach to endoscopic, pathological and clinical management. E-PS-06-060 Multifocal small bowel adenocarcinoma which is developed in the setting of Crohn's disease: a case report C. Ozturk 1 , T.B. Ozcan 1 , H.E. Pasaoglu 1 1 Bagcilar Training and Research Hospital, Turkey Background & Objectives: Small bowell adenocarcinoma occurs very rarely in patients with Crohn’s disease (CD). Here multifocal small bowel adenocarcinoma developed in the setting of CD is presented. Methods: 62 year old male admitted to our hospital with persistent abdominal pain after an hernia operation. In clinical history the patient had intermittant abdominal pain that migt related with inflammatory bowel disease but colonoscopic examination was not performed before. Small bowell perforation was detected in emergency laparotomy. Ileum resection was performed. Macroscopically ten polypoid lesions were seen throughout the ileal mucosa. The polpys’ sizes varied between 1 cm to 3cm. The mucosal surface’ colour was brown. Ulcerated areas between the polyps and deep fissur-like ulcers were also seen. Results: Histopathologic examination of the polypoid lesions revealed poorly differentiated adenocarcinoma containing mucinous component on the background of Crohn’s disease. 8 of the polyps were high grade tubulovillous adenoma which were complicating with adenocarcinoma. Some of them were inflammatory pseudopolyps There were also deep lineer fissurs, pyloric metaplasia, cyript distortion, thickened muscularis mucosa, neuronal hyperplasia, submucosal fibrosis, linear arranged lymphoid follicules in submucosa and in subseroza in nonneoplastic bowel compatible with Crohn’s disease. Conclusion: Crohn’s disease may be presented as adenocarcinoma first. In the case of adenocarcinoma of small bowell, adjacent mucosa should evaluated for CD carefully. E-PS-06-061 Stomach: an unusual presentation of glomus tumour; a case report E. Apaydin Arikan 1 , A.N. Yildirim 1 , R.B. Girgin 1 , I.M. Leblebici 2 , O. Alimoglu 2 , G. Kir 1 1 Istanbul Medeniyet University, Department of Pathology, Turkey, 2 Istanbul Medeniyet University, Department of General Surgery, Turkey Background & Objectives: Glomus tumour is a mesenchymal tumour usually occurs in the peripheral soft tissue, especially in subungal region. Although gastric glomus tumours are extremely rare, it is important to be aware of this entity because of involving in the differential diagnosis of gastric submucosal tumours. Methods: We report a 42-year-old women presenting with anemia. Results: Endoscopy revealed a submucosal mass at the antrum, but endoscopic biopsy taken from the lesion was nondiagnostic. A computed tomography showed a well-demarcated solid mass and a gastric wedge resection was performed with the initially diagnosis of gastrointestinal stromal tumour (GIST). In macroscopic examination, underlying the normal appearing mucosa, a 2.8x2.7x2 cm mural mass was observed. Microscopically, it was composed of solid sheets and island of small, round to oval uniform cells with very suspicious for neuroendocrine tumour. Immunohistochemically, tumour cells were strongly positive with smooth muscle actin and focally positive with CD34. Neuroendocrine tumour and GIST were excluded based on the negativity of chromogranin, synaptophysin, CD117 and DOG1. S100, HMB45, melan-A, desmin and caldesmon were also negative. Conclusion: Pre-operative diagnosis of gastric submucosal lesions can be challenging and glomus tumour should be considered in the differential diagnosis. The light microscopic findings of glomus tumour may mimic neuroendocrine tumour, epithelioid GİST and leiomyoma. Combination of histological and immunophenotypic findings is crucial for proper diagnosis. E-PS-06-062 Duodenal gastrointestinal stromal tumour: clinical, histopathological and immunohistochemical features - a series of 5 cases G. Terinte-Balcan 1 , A.M. Cohn 1 , S. Enache 2 , V. Herlea 3 , G. Becheanu 3 1 Emergency University Hospital, Bucharest, Romania, 2 Victor Babes National Institute of Pathology, Romania, 3 Fundeni Clinical Institute, Bucharest, Romania Background & Objectives: The term “gastrointestinal stromal tumour” (GIST) was first used by Mazur and Clark in 1983. They represent the most common mesenchymal neoplasm of the gastrointestinal tract. They are usually found in the stomach (50-60%) and in the small intestine (30-40%). Duodenal GISTs represent less than 5% of all cases. Methods: We conducted a retrospective study of the duodenal GIST diagnosed at Victor Babes Institute of Pathology, Histopathology and Immunohistochemistry Department between 2015 - 2019 and selected 5 cases. We used the following criteria in order to evaluate them: age, sex, macroscopy, histology and presence of metastases. Furthermore, we performed a large panel of immunohistochemical markers, which included at least DOG1, CD34, CD117 and Ki67. Results: Of the 5 cases, one of them was male. The median age was 64.2 years (range 48 – 80 years). The size of the tumours varied between 1 and 9 cm, with an average size of 2.9 cm. All cases were described as a proliferation of spindle cells, organized in whorls or short intersecting fascicles. The mitotic count was less than 5/50 HPF. The tumours were positive for CD117, DOG1 and CD34, except for one case that was positive only for CD34. Conclusion: GISTs located in the duodenum represent a very rare entity and require a high level of suspicion in order to be correctly diagnosed. The prognosis of this tumour is uncertain, mainly because of the small number of cases that have been reported so far. E-PS-06-063 24 neuromas of the appendix: a study of retrospective appendectomy specimens in King Chulalongkorn Memorial Hospital D. Thirabanjasak 1 , L. Sansopha 2 1 Department of Pathology, Faculty of Medicine, Chulalongkorn University and Chulalongkorn Hospital, Thailand, 2 Department of Pathology, Chulalongkorn Hospital, Faculty of Medicine-Chulalongkorn University, Thailand Background & Objectives: Neuromas of the appendix or so-called fibrous obliteration, the common benign finding of appendectomy specimen that is not harmful but charming to the pathologist. Neuromas of the appendix is a unique pathologic lesion. The lesion is composed of proliferation of S-100 positive spindle cells, admixed with benign adipocytes and fibrous stroma. The lesion is commonly found in both appendectomy specimens and surgically removed specimens. Awareness of neuromas of the appendix should be helpful for surgery planning in eldery or related risky patients. Methods: Retrospective study for appendix specimen was examined, during 2014-2018. Archives in Department of Pathology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital found 1,641 cases of appendix. 24 cases of neuromas of the appendix, 24 cases of mucinous neoplasm of appendix, 9 cases of diverticulum of the appendix, 6 cases of neuroendocrine tumour of the appendix, 3 cases of endometriosis at the appendix, 1 Kaposi Sarcoma at the appendix, 1 lymphoma at the appendix, minority of metastatic carcinoma and the rest is about the inflammation of the appendix (both appendicitis and periappendicitis). 24 neuromas of the appendix were studied, with IHC for S-100 and NSE. Results: Patients with neuromas of the appendix is majority female (Sixteen female and eight male). The minimum age is 21 and the maximum age is 87. Mean age is 56.75. Diameter and length of the appendix were studied (Length : min 3.0 cm, max 7 cm, and mean 4.3 cm) (Diameter : min 0.3 cm, max 0.7 cm, mean 0.44 cm). The spindle cells are stained for NSE and S-100. Conclusion: Neuromas of the appendix are common and benign finding. It is one of the most common finding in the appendix that is not harmful. In case there is periappendicitis, it should be precaution for surgeon to look for any other accompanying condition that can lead to appendicitis-like pain. E-PS-06-064 Microsatellite instability in gastric cancer G. Setdikova 1 , I. Tin'kova 1 , O. Paklina 1 , D. Rotin 1,2 1 Botkin Clinical hospital, Russia, 2 Hospital Haim Sheba, Tel-ha-Shomer, Ramat Gan, Israel Background & Objectives: Gastric cancer is the most common malignant tumour. Males are affected 1.3 times more than women, and the age of patients is usually 50 years and older. MMR definition in gastric cancer plays important prognostic role. Methods: The study based on material obtained after surgery in Moscow Botkin hospital, and the group was 107 patients (age range 31-82) with surgical gastric resection during 2018, where MMR was evaluated. IHC panel of 4 antibodies was used including MLH1, MSH2, PMS2, MSH6. Results: MMR was identified in 14 out of 107 cases. Type of MMR was MLH1-/PMS2- (11/14), PMS2- (3/14). No cases was negative both proteins MSH2 and MSH6, or MSH2 or MSH6. Histologically was significant predominance of Adenocarcinoma (total -12, G1-1, G2-2, G3-9), 2 cases belonged to signet ring cell carcinoma. 11 of 14 of MMR+ tumours had pT3 stage, 1 - pT2 , 2 - pT4a stage. Conclusion: In our study of gastric cancer MMR was 13% cases. There were no cases of Lynch Syndrome or other family abnormalities. E-PS-06-066 Gastric plexiform fibromyxoma - a mimicker of GIST: a case report E. Caranfil 1,2 , D.G. Ciobanu Apostol 1,2 , D.I. Franciug 2 1 "Grigore T.Popa" University of Medicine and Pharmacy, Iasi, Romania, 2 Emergency County Hospital Spitalul Sfântul Spiridon Iași, Romania Background & Objectives: Gastric plexiform fibromyxoma is a rare and unique tumour of the stomach located mainly in the antrum. Up to date less than 100 cases have been reported. Most patients present with anemia, melena, hematemesis, abdominal pain and distension. We present a case of a 34-year old woman, admitted to the emergency department for melena and moderate anemia. Endoscopy followed by CT scan revealed an antral mass suspected to be a GIST. Gastroduodenostomy (Bilroth I) was subsequently performed. Methods: Tissue samples were routinely processed. HE stains and immunohistochemical tests were performed. Results: Grossly the gastric fragment presented a nodular intramural tumour (5,1x4,7x2,6 cm) with mucosal ulceration. Microscopically, the tumour presented multiple submucosal and intramural nodules, with plexiform growth, composed of bland spindle cells, with low mitotic activity situated in an occasionally collagenous fibromyxoid stroma, with proeminent small vessels and lymphoplasmacytic inflammatory infiltrate. The adjacent gastric mucosa presented features of chronic gastritis and incomplete intestinal metaplasia. The tumour cells were diffusely positive for SMA, H-caldesmon, focally positive for Desmin, CD10. DOG1, CD117, CD34, ALK 1 stains were negative. Conclusion: Plexiform fibromyxoma is a rare entity with good prognosis and follow-up data of cases do not report recurrence or metastases. It should be distinguished from GIST which could have an aggresive course and requires a different follow-up and treatment. E-PS-06-067 Poorly differentiated gastrooesophageal carcinoma with trilineage differentiation D. Vinha Pereira 1 , G. Y. Lauwers 2 , K. Jiang 2 1 Pathology Department, Instituto Português de Oncologia de Lisboa Francisco Gentil, Lisbon, Portugal, 2 Pathology Department, H Lee Moffitt Cancer Center, Tampa, Florida, 33612 USA Background & Objectives: Gastroesophageal junction (GEJ) is an anatomical controversial location with neither consensual definition nor universally reproducible landmarks. Neoplastic lesions of this location are particularly challenging. Regardless the precise anatomical site of origin and ethiopathogenic process, carcinomas of GEJ have similar histomorphology and behavior of the correspondent counterparts in oesophagus and stomach. Poorly differentiated carcinomas could include a variety of lineages of differentiation, with distinct prognoses. The identification of each component could be challenging (histopathologically and immunophenotypically), and rarely more than two lineages have been reported. Methods: We describe the case of a 56-year-old patient presented for second opinion regarding his recently diagnosed GEJ tumour. The outside diagnosis stated poorly-differentiated adenocarcinoma. Results: Review of the outside biopsy identified a poorly-differentiated tumour with definitive adenocarcinoma histomorphology and peculiar features suggestive of neuroendocrine differentiation; indeed, both were confirmed (positive CDX2, synaptophysin and chromogranin immunostains performed at our institute). Remarkably, P40 was also positive in foci of cells. The histomorphology and immunophenotypes are most consistent with trilineage differentiation, a rare and poorly described entity. Conclusion: To our knowledge this is the first GEJ carcinoma identified in a biopsy with unequivocal simultaneous trilineage differentiation (adenoneuroendocrine and squamous differentiation) without a collision tumour pattern. We believe that meticulous histomorphological evaluation and systemic immunohistochemistry are essential in reaching an accurate diagnosis, particularly in the setting of poorly differentiated carcinomas in this location. The impact of this subclassification on the clinical management and patient outcome awaits further investigation. E-PS-06-068 Desmoplastic tumour reaction, inflammatory infiltrate and colorectal cancer: how it works? R.I. Bermudez Cameo 1 , A. Sobrino Prados 1 , C. Hondler Argarate 1 , J.I. Franco 1 , M.J. Viso Soriano 1 , H.P. Almanzar Comas 1 , S. Bakali Badesa 1 , A. Arellano Alvarez 1 , N. Estrada Mallarino 1 , L. Ligorred Padilla 1 , V. Vazquez Alvarez 1 , M.A. Nasarre Perez 1 , A. Perez Ibañez 1 , L. Lazaro Villanua 1 , E. Del Valle 1 , A. Puertas 1 , M.A. Trigo Cebrian 1 1 Hospital Universitario Miguel Servet Zaragoza, Spain Background & Objectives: A pronounced desmoplastic tumour reaction (DTR) was associated with a reduced immune response, and has been related to be a poor prognosis indicator in colorectal cancer and cancer recurrence. However, CRC with a prominent inflammatory infiltrate, which is composed of intraepithelial (TIL) and peritumoural (PTL) lymphocytes, is predictive of a better prognosis. This study sought to investigate the relation between DTR with low rate of TIL and high rate of PTL in CRC. Methods: The study included 109 patients with CRC who had undergone surgery from 2009 to 2011 at a single institution (University Hospital ‘Miguel Servet’ of Zaragoza (Spain)). They were categorized according to: TNM protocols of the American Joint Committee on Cancer (AJCC) as pT3 N0 M0, DTR, TIL and PTL status. Adjustment was made for relate low rate of TIL and high rate of PTL with a pronounced DTR. All biopsies were examined with Hematoxylin and Eosin and TIL and PTL were controlled by CD3 and CD8 immunohistochemistry (Polyclonal Rabbit anti-human CD3- Dako Omnis; Monoclonal Mouse anti-human CD8-Dako Omnis). Results: The 51% of the patients were men (56/109) and 49% were women (53/109). Also 33% (36/109) of the total group were death by the end of this study. Low rate of TIL was present in the 61% of the patients with a DTR, in comparison with the 18% with high rate of TIL (25/41 and 7/41 respectively). Also 22% had moderate rate of TIL (9/41). About PTL, only 20% of patients with DTR and low rate of TIL were high rate of PTL. Conclusion: Low rate of TIL was more frequent in patients with desmoplastic tumour reaction, which can be explained because of the resistance wielded by the tumour reaction in the stroma. However, our sample was not big enough to conclude with a high impact result, indicating the need of further investigations. E-PS-06-070 Uncommon metastatic disease of colon carcinoma - report of two cases R. Caetano Oliveira 1 , V. Sousa 2 , î Jesus 1 , P. Teixeira 1 , R. Vieira 3 , M.J. Julião 1 , J.G. Tralhão 4 , M.A. Cipriano 1 1 Pathology Department, CHUC, Coimbra, Portugal, 2 Institute of Anatomical and Molecular Pathology, Faculty of Medicine of the University of Coimbra, Coimbra, Portugal, 3 Dermatology Department, CHUC, Coimbra, Portugal, 4 Surgery Department, CHUC, Coimbra, Portugal Background & Objectives: Signet ring cell carcinoma (SCRC) of the colon is a rare entity, sometimes in association with a mucinous component, which possesses an aggressive potential and even in cases with complete resection justify a long-term follow-up. We report two cases of a SCRC with uncommon cutaneous metastases. Methods: Two male patients, one with 70-year-old referred to the Dermatology department for suspicion of perioribitary sweat gland adenocarcinoma and other with cutaneous lesions in the lower right leg. Both were previously subjected to colectomy for PCCC of the colon 10 and 15 years ago, respectively. None had previous records of metastatic disease. Results: Both lesions exhibited a diffuse and poorly cohesive cell neoplasia, with wide fatty tissue infiltration, without microsatellite instability. After six months, both patients are alive but with disseminated cutaneous lesions and under chemotherapy. Conclusion: Cutaneous metastases of colorectal carcinoma are uncommon and usually reflect advanced disease. The SCRC have a diffuse pattern of dissemination, without boundaries respect, avoiding the usual routes of colorectal metastases – lung and liver, motivating a tight follow-up. E-PS-06-071 De novo colorectal carcinoma after renal and hepatic transplantation R. Caetano Oliveira 1 , H. Antunes 2 , A.M. Abrantes 3 , E. Tavares Silva 2 , R. Martins 4 , J.G. Tralhão 4 , E. Furtado 5 , M.F. Botelho 6 , M.A. Cipriano 1 1 Pathology Department, CHUC, Coimbra, Portugal, 2 Urology Department, CHUC, Coimbra, Portugal, 3 Biophysics Institute, FMUC, Coimbra, Portugal, 4 Surgery Department, CHUC, Coimbra, Portugal, 5 Hepatic Transplantation Unit, CHUC, COimbra, Portugal, 6 Biophysics Unit, FMUC, Coimbra, Portugal Background & Objectives: Solid organ transplantation (SOT) is effective for the treatment of certain diseases, however has some risk associated, namely development of neoplasias. Immunosuppression has been appointed as higher risk for colorectal cancer (CCR) development. Our objective is to study the incidence as well as the clinical and pathological characteristics of de novo CCR after renal and hepatic transplantation. Methods: Retrospective study of patients with CCR diagnosis at ours institution between Jan/2004 and Dec/2016, previously submitted to renal/hepatic SOT. Results: 12 patients (10M:2F), median age 60.54±13.41years, from which 9 were submitted to surgery – CCR in the right colon in 5 patients (41.7%) and in the left colon on 7 patients (58.3%), none on rectum. 5 patients were previously subjected to hepatic SOT – incidence 1:151. CCR developed after a median of 55.2±26,13months after SOT, with a median of 58±10,19years. 7 patients were submitted to renal SOT – incidence de 1:380. CCR developed after a median of 117.85±76.97months, with a median of 61.43±16.65years. After a median of 16.9±6,7months all the patients are dead. Tumours were mainly of higher stages (N=7), especially in the renal SOT cohort and revealed overexpression of cancer stem cells (CD133, CD44, ALH1). There were large areas of necrosis and low density of immune population. There was no expression for PD-L1 and through CD56 expression there were no NK cells. 4 patients were MSI and 5 were P53 mutated. Conclusion: CCR after SOT has an aggressive behavior. Selected cases may benefit from individualized therapy; however, surgery and early detection seem to be the key. E-PS-06-072 High grade appendiceal mucinous neoplasm; a new classifıcation is obligatory R.B. Girgin 1 , T. Soylemez 1 , E. Apaydin Arikan 1 , H. Seneldir 1 , G. Kir 1 1 Istanbul Medeniyet Universitesi, Department of Pathology, Turkey Background & Objectives: Epithelial tumours of appendix range in a wide spectrum and their nomenclature has been a subject of debate for many years. Here we present a case of high grade mucinous appendiceal neoplasm (HAMN) and we want to discuss this entity through this case. Methods: A 41 years old male patient was admitted to emergency service with symptoms of acute abdominal pain. Computerized tomography revealed that a dilated cystic lesion of 6 cm diameter compatible with appendiceal lesion and the radiologists mentioned that they could not rule out a tumoural process . Thus the patient underwent surgery. Results: Intraoperative examination revealed that there was no mucinous material in the abdominal cavity. Macroscopically appendix was cystically dilated, creamy white and measured 6x6x4 cm. Microscopic evaluation revealed that this cystic lesion was lined by papillary and cribriform arranged epithelium. These epithelial cells displayed loss of polarity, full thickness nuclear stratification and high grade cytologic atypia. The appendix was totally submitted and did not exhibit infiltrative invasion. Conclusion: The current WHO classification has no definition that corresponds to this entity. Whereas in the litterature, the use of the term “high grade appendiceal mucinous neoplasms” is encouraged. E-PS-06-073 Colorectal cancer screening: the center of Portugal stands up with 4,6% incidence in 10 years of experience V. Almeida 1 , A. Alarcão 1,2,3 , A.F. Ladeirinha 1,2 , M. Reis Silva 1,2,3 , T. Ferreira 1,2 , A.I. Rodrigues 1 , V. Sousa 1 , L. Carvalho 1 1 Institute of Anatomical and Molecular Pathology, Faculty of Medicine of the University of Coimbra, Coimbra, Portugal, 2 CIMAGO - Research Center for Environment, Genetics and Oncobiology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal, 3 Centre of Pulmonology, Faculty of Medicine of the University of Coimbra, Portugal Background & Objectives: In Portugal, as in other European countries, the recommended primary screening test for colorectal cancer starts with the guaiac-based Faecal Occult Blood Test (gFOBT) directed to asymptomatic population with no risk factors between 50 and 74 years-old. This strategy is followed by total colonoscopy in positive gFOBT cases. Screening implementation had a previewed raise of colorectal carcinomas diagnosed without symptoms. Screening of 10 years-period and synchronous lesions were reviewed. Methods: The registry between 2008 to 2018 corresponded to polypectomies of 1576 patients submitted to a colonoscopy following the positive gFOBT as part of the colorectal cancer screening programme. Colorectal adenocarcinomas and concomitant polyps were reviewed. Results: From the 1576 patients/cases tested, 4,63% (78) were diagnosed with adenocarcinoma, which is under the 10% recognizes by European Union Recommendation on cancer screening (2017). From those 78 cases, 51 belonged to men. The median age of affected patients was 64. The most frequent localization was the sigmoid colon. The diagnosed carcinomas were alone in 33 cases and the other 45 endoscopic examinations revelled synchronous polyps, and all were biopsied or submitted or polypectomy. The most common type was tubular adenomas followed by tubulovillous adenomas. The serreated morphology was the least prevalent. Conclusion: The screening program is not yet homogenously implanted in all territory, but the actual sampling is relevant to recognize the favourable prevention and Health Minister commitment. Data from other studies revealed that the percentage of positive CCR for work-up of a positive gFOBT is around 4%, which is in line with our results. E-PS-06-074 Sall4 expressing gastric carcinoma with high serum afp level; is it possible to rule out a burned out yolk sac tumour metastasis? R.B. Girgin 1 , T. Soylemez 1 , A.N. Yildirim 1 , E. Apaydin Arikan 1 , G. Kir 1 1 Istanbul Medeniyet University, Department of Pathology, Turkey Background & Objectives: SALL4 has been identified as a diagnostic marker of germ cell tumours. Recent studies showed that SALL4 may act as an onco-fetal or carcinoembryonic molecule İN some neoplasms of extragonadal organs. AFP-producing gastric carcinomas accounts for 2.7%-5.4% of all gastric carcinomas with some of them containing germ cell components which explains retrograde differentiation of neoplastic cells. Methods: 60 years-old male patient was investigated for abdominal pain. Endoscopic examination revealed an ulcerous lesion at the corpus-antrum junction and the serum AFP level was >20000 ng/mL. No mass was detected in testis nor a previous tumour was present. Results: Microscopic examination revealed a poorly differantiated tumour with focal trabecular areas and with clear cell areas which lacked mucin and glycogen accumulation with Alcian blue and PAS stain, respectively. Tumour cells were diffusely positive for CDX2, SALL4, Glipycan 3, AFP and EMA. No mass was detected in testis nor a previous tumour was present. PET scan was unremarkable except stomach. Conclusion: It should be kept in mind that AFP-producing gastric carcinoma and yolk sac tumour share similar morphologic and immunhistochemical features. EMA positivity support the diagnosis of gastric carcinoma based on the knowledge that germ cell tumours are negative for EMA. E-PS-06-075 Clear cell sarcoma of the digestive tract: a case report R. Narjess 1 , N. Boujelbene 2 , I. Abbes 2 , R. Doghri 2 , L. Charfi 2 , N. Kcherem 2 , K. Mrad 2 , M. Driss 2 1 Institute of carcinology Salah Azaiz Tunis, Tunisia, 2 Department of Pathology, Salah Azaiez Institute, Tunisia Background & Objectives: Clear cell sarcoma (CCS) of the gastrointestinal tract is a rare malignant neoplasm that occurs in the wall of the small bowel, stomach, or large bowel, predominantly in young adults. It is an aggressive neoplasm that frequently presents with metastatic disease and has a high mortality rate. Herein we report a case of CCS with description of the pathological and molecular features of this rare entity to make pathologists aware of this entity. Methods: A 27-year-old patient with a history of retinoblastoma consulted for dysphagia. Results: Fibroscopy shows a bulging formation of the middle 1/3 of the oesophagus. Histological examination of a biopsy shows a densely cellular tumour consisting of rounded monomorphic cells disposed in a vaguely fasciculate pattern. Tumour cells have a round or oval nucleus with a reduced eosinophilic clarified cytoplasm. The immunohistochemical study show that these cells are Pancytokeratin (-), PS100 (+), SOX10 (+), HMB45 (-), MelanA (-), Desmin (-), RB1 (+), C-kit (-), DOG1 (-), CD99 (+), SMARCB1 (+). Molecular study identified a EWSR1-ATF1 fusion transcript, which confirmed the diagnosis of a clear cell sarcoma of the digestive tract. Conclusion: The lack of familiarity of pathologists with the features of this neoplasm may have previously contributed to its under recognition, but the finding of an epithelioid or spindle cell neoplasm in or around the gastrointestinal tract with S100 protein expression should always warrant molecular assessment for EWSR1 rearrangement and for EWSR1-CREB1 and EWSR1-ATF1 fusion transcripts. E-PS-06-076 Ceacal adenocarcinoma arising from huge Traditional Serrated Adenoma located in appendix and ceacum: a case report H.E. Pasaoglu 1 , E. Erel 1 , N. Okkabaz 2 , T.B. Ozcan 1 , T. Cay 1 , N. Erdogan 1 1 Clinical Pathology, Turkey, 2 Gastrointestinal Surgery, Turkey Background & Objectives: Traditional serrated adenomas are uncommon, making –up <%1 of all colorectal polyps. They are usually found in the distal colon . Appendix and ceacum are very rare locations for TSA. The majority of TSAs are protuberant lesions smaller than 2cm. Here, we presented a case of ceacal adenocarcinoma arising from a huge, broad based traditional serrated adenoma located in appendix and ceacum. Methods: 75 year old female was admitted to clinic with abdominal pain and distention. Physical examination was normal. The patient had undergone breast conserving surgery for breast cancer four years ago. Colonoscopy revealed a 5 centimeters broad based polypoid lesion in ceacum. Intramucosal carcinoma arising from an adenoma with serrated pattern was seen in colonoscopic biopsy. Right hemicolectomy was performed. Results: Macroscopically 5,5x4 cm polypoid mass in ceacum was detected. Diameter of the appendix was 1,7 cm . Polypoid lesion was connected with the appendiceal orifice. Longitidinal section was performed from the orifice to the tip of the appendix and fingerlike projections troughout the appendix mucosa were seen. Histopathologically the lesion had a villiform growth pattern and serrated luminal surface. The cells lining the villi were tall and columnar with eosinophilic cytoplasm and pencillate nuclei. Small, abortive ectopic crypts were also seen. These features were consistent with TSA. The lesion exhibited high grade dysplasia in some areas . An adenocarcinoma containing mucinous component was detected in deep portion of the adenoma in ceacum, which was infiltrating the subseroza. Immunhistochemically MUC-2, MUC 5AC were positive, MUC-6 negative and DNA mismatch repair proteins (MLH1, MSH2, MSH6, PMS2) were diffusely expressed in nuclei in both adenoma and invasive carcinoma areas. Conclusion: The diagnosis of TSA may be difficult in small endoscopic biopsies. Furthermore, carcinoma in the deep portion of the polyp may not be detected in endoscopic biopsies . Total excision with intact surgical margin should be done. E-PS-06-077 Adenocarcinoma of anal glands with apocrine differentiation: a case report and a literature review O.B. Popescu 1 , O. Cerezo-Aranda 1 , J.M. Barria Castro 2 , L. G. Pastrián 1 , E. Palacios Lázaro 1 1 Hospital Universitario La Paz, Spain, 2 Complejo Hospitalario Dr. Arnulfo Arias Madrid, Panama Background & Objectives: Apocrine carcinoma is a rare skin appendage tumour that shows apocrine-type decapitation secretion. It occurs in the body sites where apocrine ducts are normally located. Methods: An 88-year-old male presented with a sessile polypoid lesion in the anal region. It was 2,5 cm wide, white and firm, and was surgically resected. Results: Lesion was an expansive mass of variable-sized nodules, located in lamina propria, growing in solid and cribriform patterns with eosinophilic acellular secretions. Cells had large eosinophilic cytoplasm with pleomorphic nuclei and prominent nucleoli. Numerous mitotic figures were identified. The overlying epithelium showed pagetoid spread of atypical cells, but was not intraepithelial dysplasia. Lymphovascular invasion was present and the resection margin was positive. A few mammary-type glands were seen, affected by an analogue intraductal lesion. The immunophenotype of the tumour cells was strongly and diffusely positive for CK7, GCDFP-15, androgen receptor and Her2 (3+), and negative for CK20, CK 5/6, CDX2, p63 and p40. Conclusion: Adenocarcinoma with apocrine differentiation arising from anogenital glands is uncommon and only a few cases have been published. Both genders are equally affected. Pathogenesis is unknown, but it seems to arise from apocrine hyperplasia or adenoma of anogenital mammary-like glands. Differential diagnosis includes metastatic breast cancer, benign apocrine tumours, colorectal adenocarcinoma and mucinous carcinoma. Treatment is wide excision. E-PS-06-078 PDL-1 expression is poor prognostic factor in gastric carcinomas? S. Erdamar 1 , S. Bahsi 1 , Į Yıldız 1 1 Acibadem University Medical College, Turkey, College, Turkey Background & Objectives: PDL1 expression and Microsatellite Instability (MSI) is getting more important gastric carcinoma to get benefit from immunotherapy. In this study, we aimed to investigate the MSI status and the frequency of PD-L1 expression in gastric cancer cases and the relationship between this frequency and clinicopathological features and overall survival. Methods: The patients diagnosed with gastric cancer between the years 2010-2017 at Acibadem University Hospitals were retrospectively analysed and 86 patients were included in the study. Patients were evaluated of age, sex, tumour location, tumour size, tumour histological subtype, clinical and pathological tumour stage, HER-2 staining status, preoperative treatment status, lymphovascular and perineural invasion, resection status. Tumour sections were immunostained with MMR proteins and PD-L1 (22C3 clone). Analytical statistical methods, survival analysis was performed. Factors affecting survival were determined by univariate and multivariate analysis. Results: The incidence of MSI was 11.6% (n:10), the presence of PD-L1 expression in tumour cells was 34.9% (n:30) and the presence of PD-L1 expression in immune cells with Combine tumour score (≥1%) was 57% (n:49). PD-L1 positivity was found to be statistically higher in patients with node positive, adenocarcinoma subtype, microsatellite instability, preoperative treatment, and chemotherapy response. Conclusion: In our study, the impact of MSI status on survival was not demonstrated, but PD-L1 expression positivity was associated with short survival in both tumour cells (p:0.008) and in immune cells (p:0.027). E-PS-06-079 Synchronous presence of epithelial and stromal tumours in the stomach - characterization of molecular pathways E. Kocsmar 1 , G. Papp 2 , I. Kocsmar 1 , L. Szalai 3 , I. Kovalszky 2 , G. Lotz 1 1 2nd Department of Pathology, Faculty of Medicine, Semmelweis University, Hungary, 2 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Hungary, 3 2nd Department of Pathology, Semmelweis University, Hungary Background & Objectives: Gastrointestinal stromal tumours (GISTs) are the most common tumours in the digestive tract arising from the mesenchymal components of the tissue. Small GISTs (GIST tumourlets) are usually asymptomatic and most frequently found in gastric surgical specimens incidentally. Our aim was to assess prevalence of incidental GISTs among gastrectomy specimens of gastric adenocarcinoma patients and to obtain data about molecular mechanisms of these synchronous tumours. Methods: Gastrectomy specimens obtained between 2002-2018 were selected from the institutional register of the 2 nd Department of Pathology. Incidence of incidental GISTs was also assessed separately according to the method of resection (partial or total). Patients with adenocarcinoma and synchronous GIST were selected and CD117 (c-kit), CD34 and DOG1 immunohistochemical stainings were performed on both tumours. KIT exon 9, 11, 13, 4, 17 mutations were analysed by Sanger sequencing. Results: 1,027 gastrectomy specimens were analysed in the study period, including 665 cases of patients operated due to adenocarcinoma. Synchronous incidental GIST was found in ten cases (1.5% of 665). All of the GIST tumourlets were of spindle cell variant and immunohistochemically positive with CD117, CD34 and DOG1. Positive DOG1 immunostain was detected in four adenocarcinomas as well. KIT mutation was found in four GISTs, but in none of the synchronous adenocarcinomas. Conclusion: Incidence of incidental GISTs in gastrectomy specimens was lower in our cohort than in other studies. Although a common carcinogenic effect cannot be ruled out, our data suggest that distinct mechanisms play role in the development of synchronous GISTs and gastric adenocarcinomas. This study was partly supported by New National Excellence Program of the Hungarian Ministry of Human Capacities (ÚNKP-18-3-I-SE-44), EFOP-3.6.3-VEKOP-16-2017-00009, and Semmelweis Start-up Research Grant. E-PS-06-081 Correlation between different histopathological indices and clinical parameters in children with ulcerative colitis J. Jevtic 1 , R. Jankovic 2 , S. Strizovic 2 , D. Obradovic 1 , N. Ristic 3 , N. Dragutinovic 3 , I. Milovanovic 3 , M. Radusinovic 3 1 Faculty of Medicine, University of Belgrade, Serbia, 2 Institute of Pathology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia, 3 University Children's Hospital, Serbia Background & Objectives: A diagnosis of ulcerative colitis (UC) requires multidisciplinary approach. Among wide variety of diagnostic modalities histopathology still stands as the diagnostic gold standard. Since the histological remission is the main goal in treatment of UC, assessment of disease activity during endoscopy and histopathological examination is of paramount importance. The aim of the study is to determine the correlation between different histopathological scores (Geboes and Nancy) in biopsies of the children with UC, endoscopic Mayo score (EMS) and clinical overview. Methods: Colonic biopsies of children with UC from the Institute of Pathology, Medical Faculty, University of Belgrade were retrospectively analysed, as well as clinical data and endoscopic characteristics collected from University Children’s Hospital in period of three years (2016-2018). Results: We analysed 243 endoscopic biopsies of 41 children with newly diagnosed UC as well as specimens after treatment. The average age of patients was 12.8±4.39 years. Majority of patients were male (53.66%). Twelve percent of patients had extraintestinal manifestations of the disease with the primary sclerosing cholangitis as the most common. Statistical analysis showed significant moderate correlation between histopathological scores and EMS, and significant strong correlation among histopathological scores. We found slightly stronger correlation between histopathological scores and EMS in children with newly diagnosed UC than after treatment. Conclusion: There is strong statistically significant correlation between histopathological scores (Geboes and Nancy). Therefore both of the histopathological scores can be successfully applied in estimation of disease severity. E-PS-06-083 Correlation of tumour budds, epidermal growth factor 2 and exspression of E-cadherin with overall survival of patients with advanced gastric adenocarcinoma M. Cuk 1 , R. Gajanin 2 , S. Kulic 1 , M. Vasic Milanovic 3 1 University of East Sarajevo, Faculty of Medicine Foca, Department of Pathology, Bosnia and Herzegovina, 2 University of Banja Luka, Faculty of Medicine, Department of Pathology, Bosnia and Herzegovina, 3 Public Health Hospital, Department of Pathology, Zvornik, Bosnia and Herzegovina Background & Objectives: Adenocarcinoma of the stomach is very aggressive biological behavior and has a poor prognosis in patients in an advanced stage of the disease. Testing new prognostic parameters and discovering new therapeutic targets is a long-standing challenge for pathologists and oncologists. Methods: Tumour buds were determined on the invasive edge of the tumour and defined as individual or groups of less than five tumour cells. Paraffin-embedded tumour samples were examined for E-cadherin, CK20 and HER2 using immunohistochemistry. Additionally, gene amplification was examined using fluorescent in situ hybridization (FISH) for HER2. Results: The minimum follow-up period was 6 months and a maximum follow-up period of 87 months. The survival rate of patients after 12 months was 80.2%, after 24 months 51%, after 36 months 28.5%. Budding was present in 76 of 96 cases and was associated with decreased overall survival (OS) (Log Rank=32,805, p<0.001). Reduced expression of E-cadherin was identified at the frequency of 74% and was associated with decreased overall survival (Log Rank=23,80, p<0.001). There was a significant difference in OS between HER2-positive and HER2-negative patients [median, 17.0 vs. 26.0 months; p < 0.01]. Multivariate analysis showed that high grade of tumour budding was an independent prognostic factor for overall survival [hazard ratio, 1,46 (95 % confidence interval, 1,25 – 1,69); p<0.01], but HER2 and E-cadherin did not show themselves as independent prognostic parameters. Conclusion: Tumour budding is significant and independent predictors of poor outcomes in patients with advanced gastric adenocarcinoma. Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-07 | Digestive Diseases Pathology – Liver / Pancreas Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-07 | Digestive Diseases Pathology – Liver / Pancreas E-PS-07-001 Hepatocellular adenoma like associated with vascular obstructive disease secondary to alcohol consumption A. Vera-Torres 1 , L. Barrera 2 , M. Tapias 1 , J. Alvarez-Figueroa 2 1 Transplant and Hepatobiliary Surgery Service, Hospital Universitario Fundación Santa Fe de Bogotá Colombia, 2 Department of Pathology and Laboratory Medicine, Hospital Universitario Fundación Santa Fe de Bogotá, Colombia Background & Objectives: Hepatocellular nodules are commonly observed in hepatic vascular disorders and the lesions that resemble a hepatocellular adenoma share the same characteristics as a conventional hepatocellular adenoma. We present a lesion that resembles a hepatocellular adenoma associated with a hepatic vascular disorder secondary to alcohol consumption. Methods: 64-year-old man with history of alcohol consumption, diabetes mellitus and variceal bleeding. The CT scan show liver with normal contours and diminish of size with prominence of the caudate lobe, permeable vascular structures and focal poorly defined 25 mm lesion. Results: Liver examination revealed micronodular surface and microscopically heterogeneous architecture, both severe and slight nodular areas, significant sinusoidal dilatation, hemorrhage and blood vessels destruction associated with hepatocellular lesions with cholangiolar proliferation, chronic inflammation and telangiectasia with CD34, FVIII and SAA reactivity, with low cell proliferation index and negativity for glutamine synthetase and Betacatenin. The reticular pattern was preserved without presence of malignant hepatocellular lesion. Conclusion: Obstructive vascular disease can be seen in alcoholic patients. Fibrosis after abstinence may improve and steatohepatitis characteristics would be lost. Lesions similar to hepatocellular adenoma (inflammatory/telangiectasic adenoma morphology) present with an immunophenotype similar to the observed on conventional hepatocellular adenoma. This lesion associated with hepatic vascular disorders, may increase the risk of malignant transformation compared to a conventional hepatocellular adenoma. E-PS-07-002 Adult hepatic Langerhans cell histiocytoris associated with chronic colangiopaty M. Rolon 1 , M. Romero 1 , C. Saavedra 1 , D. Cañon 1,2 , L. Barrera 1 , A. Vera-Torres 3 , M. Tapias 3 , J. Alvarez-Figueroa 1 1 Department of Pathology and Laboratory Medicine, Hospital Universitario Fundación Santa Fe de Bogotá, Bogotá, Colombia, 2 Universidad de los Andes. Bogotá, Colombia, 3 Transplant and Hepatobiliary Surgery Service, Hospital Universitario Fundación Santa Fe de Bogotá. Bogotá, Colombia Background & Objectives: Langerhans cell histiocytosis (LCH) is a rare neoplasm characterised by the presence of positive CD1a histiocytes. Predominates in the paediatric age with cutaneous lesions as the first manifestation. We present a case of an adult with hepatic involvement associated with chronic damage of the bile duct without cutaneous manifestations. Methods: 47-year-old male with history of diabetes insipidus and one year of multiple episodes of acute cholangitis associated with abdominal pain, jaundice, high bilirubin direct levels, transaminases and alkaline phosphatase. AMA negative. The cholangioresonance reveled global hepatomegaly with alteration of parenchymal intensity and stenosis of the intrahepatic bile duct. Results: Liver biopsy showed architectural distortion, portal fibrosis, portal spaces with inflammatory infiltrate composed by histiocites, lymphocites, plasma cells, foamy histiocytes and abundant eosinophils, granulomas and bile duct damage with aberrant expression of cytokeratin 7 at periportal level and ductular reaction with acute cholangiolitis. Hepatocanalicular cholestasis, xanthomatous change with periportal copper deposits. CD1a and s100 positivity in the portal histiocytes. The patient was subjected to chemotherapy and with morphologic remision pending for trasplantion. Conclusion: Although adult presentations of LCH is described in the literature this patient's age is unusual. As a morphological finding, we shown that the presence of granulomas with histiocytes and eosinophils in biopsies should be considered as a suspicious finding for LCH and Hodgkin lymphoma and Mastocytosis should, however, be consider in the differential diagnosis. E-PS-07-003 Intracranial meningeal hemangiopericytoma metastatic to the liver J. Alvarez-Figueroa 1 , L. Barrera 1 , A. Vera-Torres 2 , E. Jimenez-Hakim 3 , P. Escalante 1 1 Department of Pathology and Laboratory Medicine, Hospital Universitario Fundación Santa Fe de Bogotá. Bogotá, Colombia, Colombia, 2 Transplant and Hepatobiliary Surgery Service, Hospital Universitario Fundación Santa Fe de Bogotá, Colombia, 3 Department of Surgery, Hospital Universitario Fundación Santa Fe de Bogotá, Colombia Background & Objectives: Solitary fibrous tumour/The hemangiopericytoma is a mesenchymal central nervous system tumour of uncommon fibroblastic origin, when the phenotype corresponds to a hemangiopericytoma there is an increased risk of extracranial metastases, which usually occur several years after the initial diagnosis. We present a case of metastatic meningeal hemangiopericytoma to the liver. Methods: A 42-year-old female patient with a history of recurrent extra-axial tumour, who presented abdominal induration sensation 9 years after the initial diagnosis. Multiple solid hepatic lesions with heterogeneous cystic components and peripheral enhancement were documented on CT scan. Patient was submited to right hepatectomy and segmental resection of lesions in the left lobe. Results: Histopathological study reveladed a malignant, hypercellular mesenchymal neoplasm, consisting of cells with rounded to oval nuclei, vesicular and condensed chromatin, some cells with epithelioid appearance, arranged in a disorganized architectural pattern, thin-walled blood vessels cells and up to 8 mitosis in 10 HPF. Immunohistochemical showed diffuse and strong positivity of neoplastic cells for CD34, BCL-2, CD99 and Vimentin, with focal and weak positivity for Progesterone Receptors and negativity for EMA and Desmin. Conclusion: These findings correspond to a meningeal mesenchymal tumour of hemangiopericytic morphology, which is part of the solitary fibrous tumour/hemangiopericytoma spectrum, and it is classified as WHO 2016 grade III, metastatic to liver. These tumours should be considered as potentially malignant in all cases and hepatic metastases are rare. E-PS-07-004 Solitary fibrous tumour hepatic: case report and review of current knowledge R.M. Souza da Silva 1 , E. Moreira de Queiroga 2 , A. Rolim da Paz 3 , Á. Regina Gouveia 4 1 Federal Fluminense University, Brazil, 2 Alcides Carneiro University Hospital of the Federal University of Campina Grande, Brazil, 3 University Hospital Lauro Wanderley/EBSERH/UFPB, Brazil, 4 Faculty of Medical Sciences, Brazil Background & Objectives: Solitary fibrous tumours (SFTs) are a rare type of spindle cell neoplasm, composed of cellular and collagenous components, predominantly arise from the pleura. SFT of the liver (SFTL) are uncommon with little number of cases reported in English literature. The diagnosis is based on histological and morphological characteristics, associated with immunohistochemical markers and molecular analysis. The rarity of this tumour makes it difficult to evaluate its prognosis and natural course. Surgical resection remains the mainstay of treatment. Methods: The present study reports a new case of SFTL and has the main purpose of updating the current knowledge. Results: 42-year-old woman, with right hypochondrial discomfort and postprandial fullness. Magnetic nuclear resonance showing nodular expansive formation with well-defined contours, located in left hepatic lobe. Macroscopically, a nodular mass, white color, firm and elastic, measuring 3,2 cm x 3,0 cm.. Microscopic examination evidenced fusocellular proliferation, hypocellular and hypercellular areas (mild atypia), with predominance of a sclerotic pattern. The immunohistochemical study revealed ki-67 1%, positivity for STAT 6, CD 34 and Bcl-2. The diagnosis was of Solitary Fibrous Tumour Hepatic. Conclusion: The SFTL is rare, with only 85 cases reported in the English Literature including the present case. The clinical presentation is habitually indolent. The diagnosis is histopathological e immunohistochemical. SFTL because due to its rarity, its clinical presentation, study, treatment, and prognosis are not well known. E-PS-07-005 Chylous ascites, induced by a pancreatic carcinoma A.C. Tinca 1 , Tivadar Bara 1 , Ioan Jung 1 , Simona Gurzu 1 1 Department of Pathology, Clinical County Emergency Hospital, Tîrgu Mureș, Romania Department of Pathology, University of Medicine, Pharmacy, Sciences and Technology, Tîrgu Mureș, Romania Background & Objectives: Chylous ascites is an uncommon condition of peritoneal cavity. The aim of the paper was to describe the case of a patient with ductal adenocarcinoma of the pancreatic body that presented as acute abdomen and chylous ascites. Methods: A 76-year old previously healthy male presented with acute abdomen and suspicion of pancreatic body cancer, with associated ascites, was done. Emergent surgery consisted on splenopancreatectomy with dissection of the peripancreatic lymph nodes. The fluid from abdominal cavity had a milky aspect and was proved having lymphatic origin. Results: The 50x40x20 mm pancreatic tumour involved the pancreatic body and tail and showed direct infiltration of the spleen hilum, being diagnosed as pT3N1 ductal adenocarcinoma. Most of the lymph vessels showed tumour emboli, which induced blockage of the lymphatic flow. The patient died at three weeks after surgery. Conclusion: In patients with pancreatic cancer, chylous ascites can indicate an aggressive carcinoma with lymphatic flow blockage. This work was supported by a grant of the Romanian National Authority for Scientific Research, CNCS – UEFISCDI, project number 20 PCCF/2018, code: PN-III-P4-ID-PCCF-2016-0006. E-PS-07-006 Synchronous pancreatic stromal tumour and granulous T-cell leukemia A. Bdioui Thabet 1 , C. Pierre 2 , H. Busby 2 , N. Mhamedi 2 1 Georges Pompido Hospital Paris, France, 2 Brabois Hospital, Nancy, France Background & Objectives: Coexistence of stromal tumours with other malignancy is rarely reported, it has been described for digestive stromal tumour with adenocarcinoma, either MALT or Hodgkin lymphoma. Extra digestive stromal tumour are rare counting less than 5%, Their association with other synchronous tumours is furthermore exceptional, the case of our patient. Methods: 59-year-old man, consulting for chronic abdominal pain, radiological investigations showed a large exophytic pancreatic tumour. The patient underwent surgery, he has had caudal spleno-pancrectectomy. In gross, there was a voluminous exophytic pancreatic tumour, well limited, firm, appended to the tail; and presenting an heterogeneous cut surface. The spleen was increased in size, 20 cm of large, with homogeneous appearance. Results: Histological examination of the pancreatic mass and the immunohistochemical study concluded to a gastrointestinal stromal tumour of moderate risk of malignancy, expressing DOG 1 and CD 117.Examination of the spleen showed an infiltration by large granular T lymphocytes, with large nuclei, these cells expressed in immunohistochemistry T markers: CD2, 3, CD7 and 8 and show a loss of CD4 expression. . The molecular biology study confirms the diagnosis by showing a clonal rearrangement of the TCR gamma and betta genes. Conclusion: The association of stromal tumours with other neoplasia must search for common carcinogen or genetic predisposition, multicenter studies involving a large number of cases are necessary to confirm or refute this hypothesis. E-PS-07-007 The analysis of mortality at gallstone disease according to autopsy studies T. Vervekina 1,2 , B. Magrupov 2 1 Republican Research Center of Emergency Medicine, Uzbekistan, 2 Tashkent Institute of Postgraduate Medical Education, Uzbekistan Background & Objectives: The problem of gallstone disease in the structure of the morbidity grows steadily. Surgical activity at this pathology surpassed the number of other abdominal interventions including appendectomy. Complicated forms of the disease and combined pathology increase the level of cholelithiasis in the structure of mortality. Methods: We performed analysis of 2674 patients’ case histories with various forms of cholecystolithiasis. Fatalities were recorded in 18 patients at the age of 41-60 years, 13 of them were 51-60 years old men. Analysis of lethal outcome was carried out according to the results of autopsy studies. Results: We found that in 89% of cases an unfavorable outcome occurred at the combination of various forms of cholecystitis and choledocholithiasis. In the gallbladder were diagnosed: destructive forms of inflammation (11 cases), chronic cholecystitis (4), chronic recurrent cholecystitis (3). The third part of the lethal outcomes was in patients with a combined pathology, such as liver cirrhosis, myocardial infarction, peptic ulcer, and heart disease. The death cause in most cases was sepsis, as well as complications of combined diseases. Conclusion: The analysis showed that deaths are more often recorded in 51-60 years old men with destructive forms of cholecystitis at a lesion of the gallbladder and choledoch. Combined pathology of the digestive organs and cardiovascular systems has a significant impact on the disease outcome. E-PS-07-008 A rare case of signet-ring cell carcinoma of the gallbladder, presenting as Krukenberg tumours of the ovaries M. Kilmpasani 1 , I. Matzarakis 2 , A. Baliaka 1 , I. Dimitriadis 2 , N. Pastelli 2 , I. Karafoulidou 2 , S. Despina 2 , V. Penopoulos 2 , S. Papaemmanouil 2 1 Department of Pathology, General Hospital of Thessaloniki "G. Papanikolaou", Greece, Thessaloniki "G. Papanikolaou", Greece, 2 2nd Surgery Department, General Hospital of Thessaloniki "G. Papanikolaou", Greece Background & Objectives: Signet-ring cell carcinomas of the gallbladder are very rare and considered to have an aggressive behaviour. Krukenberg tumour of the ovary may be the first manifestation of a malignancy, and is associated with poor prognosis. We report the case of a 49-year-old woman, admitted with bilateral ovarian tumours, without any known gallbladder-related symptoms. Methods: During the surgical oophorectomy, a simultaneous cholecystectomy was performed, due to suspected metastasis to cystic duct lymph nodes. The surgical specimens were examined in FFPE sections with hematoxylin-eosin and immunohistochemical stains. Results: Two white-tan lesions of the gallbladder mucosa were observed, each measuring 1.5cm. The microscopic examination revealed a signet-ring cell carcinoma, beginning from the overlying epithelium and infiltrating the gallbladder wall. Two cystic duct lymph nodes showed metastasis from the carcinoma. Both ovaries demonstrated nodular, solid, white-tan tumours, measuring 10cm (right) and 2cm (left). The microscopic findings were similar to the aforementioned carcinoma in the gallbladder. Among others, the neoplastic cells stained positive for Ck7 and Ck19, and negative for Ck20, vimentin, CD15 and a-fetoprotein. Consequently, the ovarian tumours were diagnosed as metastases of the carcinoma of the gallbladder. Conclusion: It is a challenge to differentiate primary from metastatic carcinoma of the ovaries. Krukenberg tumours are ovarian tumours of metastatic origin, with a diffuse infiltration by signet-ring cells. A primary malignancy in the gallbladder is rarely encountered. Only few cases of primary signet-ring cell carcinoma of the gallbladder are described in the literature, and they are frequently associated with locally infiltrative behaviour and distant metastases. E-PS-07-009 Immunohistochemical study of cell proliferation in hepatocellular carcinoma R.A. Barna 1 , M. Cornianu 2 , D. Lazar 3 , N. Basa 4 , S. Taban 5,6 , A. Dobrescu 7 , F. Lazar 8,9 1 Department of Pathology, University of Medicine and Pharmacy „Victor Babes", Timisoara, Romania, 2 V. Babes University of Medicine and Pharmacy, Romania, 3 Internal Medicine Department IV, University of Medicine and Pharmacy „Victor Babes", Timisoara, Romania, 4 Internal Medicine Department I, University of Medicine and Pharmacy „Victor Babes", Timisoara, Romania, 5 Emergency Clinical County Hospital ''Pius Brinzeu'' Timisoara, Romania, 6 ''Victor Babes'' University of Medicine and Pharmacy Timisoara, Department of Pathology, Romania, 7 Surgery Department II, University of Medicine and Pharmacy „Victor Babes", Timisoara, Romania, 8 Surgery Department II, "Victor Babeş" University of Medicine and Pharmacy, Timișoara, Romania, 9 Surgery Department II, Emergency County Hospital Timișoara, Romania Background & Objectives: The aim of this study was to evaluate the proliferative activity of neoplastic and non-neoplastic hepatocytes, to identify possible correlations between histopathological features of HCC and its proliferation rate and to establish the role of Ki-67 as a prognostic factor in patients with radical surgery of HCC. Methods: Assessment of the proliferative activity was made using monoclonal Ki-67 antibody, clone MIB-1 ready-to-use. To appreciate the proliferation index of Ki-67 (PI Ki-67), it has been used the semi-automated method of counting the nuclei on digital images. The study included 32 surgically removed liver carcinomas. In order to compare results, it was included a group of non-tumour lesions obtained by liver biopsy. Results: Mean value of Ki-67 index was 0.4% ± 0.2% in normal liver, 3.52% ± 0.2% in non-tumour liver lesions and 13.4% ± 7.7% in HCC (p<0.001). Mean value was 5.2% in portal chronic hepatitis and 5.5% in active chronic hepatitis with cirrhotic evolution. 66.6% of HCC associated with HBV infection and 66.6% of HCC developed from a cirrhotic lesion had a high Ki-67 score. High proliferation rate was correlated with presence of intrahepatic metastasis (p<0.001) and with vascular invasion (p<0.001). Conclusion: Differences between the proliferation rate of HCC and non-tumour liver lesions (p<0.001) show that the uncontrolled division of tumour cells can play an important role in the development of HCC. Ki-67 expression as a prognostic factor can be used to select the right therapy for hepatocellular carcinoma and may be a future target for molecular therapy. E-PS-07-010 Epstein Barr Virus-associated smooth muscle tumour: a case report C. Fumagalli 1 , E. Chenu 1 , S. Novelli 1 , J.C. Pernas 1 , A. Mozos 1 , J. Szafranska 1 1 Hospital de la Santa Creu i Sant Pau, Spain Background & Objectives: Epstein Barr virus associated smooth muscle tumour (EBV-SMT) is an under-recognized entity that usually occurs in immunosuppressed patients. Herein, we present a case of EBV-SMT affecting a post-transplant female. Methods: The patient, an 18-year-old female with a history of T-cell lymphoproliferative disorder, was treated with bone marrow transplant in 2012. In CT scan, a well-defined mass (44 mm) was found in the liver and, due to its hypervascular pattern, a tru-cut biopsy was performed. Histological examination showed a neoplasm consisting of spindle cells arranged in small fascicles with elongated cigar-like nuclei and an eosinophilic cytoplasm. No cytological atypia was found and the mitotic activity was low (Ki67<5%). Results: Immunohistochemistry highlighted that tumoural cells expressed smooth muscle actin and caldesmon. In situ hybridization for Epstein-Barr virus (EBV) was strongly positive, while the EBV protein late membrane protein 1 (LMP1) was negative. Based on these findings, EBV-SMT was diagnosed. A conservative management was established and the patient was treated with Sirolimus. A control performed five months later showed persistence of active EBV infection and stability of the lesion. Nonetheless, due to collateral effects, immunosuppressive therapy was retrieved. Conclusion: EBV-SMT has been described in patients infected with HIV, in the posttransplant setting, and in those with congenital immunodeficiency. In the present case it affected the liver of an immunosuppressed patient. Due to its rarity, it might inadvertently be misdiagnosed as a leiomyoma. There isn’t an established treatment for this tumour, but a correct diagnosis would avoid overtreatment. E-PS-07-011 Histological features and dynamics of colorectal metastasis in the liver C. Fumagalli 1 , E. Chenu 1 , B. Martin 1 , I. Gich 1 , D. Paez 1 , J.C. Pernas 1 , V. Artigas 1 , J. Szafranska 1 1 Hospital de la Santa Creu i Sant Pau, Spain Background & Objectives: Colorectal cancer (CRC) is the third most prevalent cancer worldwide and liver is the most common site of CRC metastases (CRCLM).Hepatic resection of CRCLM remains the standard of treatment, sometimes associated with neoadjuvant chemotherapy (NC). Aim of the study was to analyse histological features within the metastases, in the tumour-liver interface (TLI) and in the non-tumoural liver parenchyma, in order to identify how the metastases modify the liver histology. Methods: The clinical history and histologic parameters were revised of 131 CRCLM resected at our institution during the period 2010-2017. The study included 95males and 48females with a median age of 67yrs and a tumour median size of 2,9cm.Among them, 82(62,6%) received NC.The histological features studied were: mucinous component, vascular-perineural-biliar invasion, growth pattern, fibrous capsule, ductular proliferation and chronic inflammation with/without lymphoid follicles in TLI and presence of portal-centrilobular-lobular inflammation, hepatocyte ballooning-acidophilic bodies, fibrosis, colestasis and rosette formation in liver parenchyma. Results: Statistical analysis was performed dividing the patients in group A (who received NC) and B (without NC).It was found that NC was associated with replacement growth pattern, absence of chronic inflammation and fibrous capsule in TLI (p <0.005),while in group B surgical hepatitis and rosette formation (p <0.005) in the no-tumoural liver parenchyma were observed. No differences in overall survival were found when comparing the growth pattern or the use of NC. Conclusion: Both CRCLM and NC could induce liver changes.In this study, it was found replacement growth pattern, absence of chronic inflammation and fibrous capsule in TLI in pts who received NC, while more prominent surgical hepatitis was curiously found in pts who didn’t receive NC. However, further research is required to understand de complex mechanisms taking place within the metastatic liver. E-PS-07-012 The conclusive utility of cell-block procedure in diagnosing rare pancreatic neoplasms through EUS-FNA approach O. Neagu 1 , M. Dumbrava 2 , B. Cotruta 2 , I. Bancila 2 , V. Herlea 2 , C. Gheorghe 2 , G. Becheanu 2,3 1 University Emergency Hospital Bucharest, Romania, 2 Fundeni Clinical Institute, Bucharest, Romania, 3 "Victor Babes" National Institute of Pathology, Bucharest, Romania Background & Objectives: EUS-FNA has become the gold standard in preoperative pancreatic masses assessment. Nevertheless, rare pancreatic neoplasms display indefinite morphology on routine cytologic smears, even for experienced cytopathologists. Adding the cell-block procedure increases the diagnosis accuracy by enabling the use of ancillary tests. Methods: We report two cases of isthmus and body pancreatic neoplasms detected during abdominal sonography in a 23-year-old and 66-year-old women, respectively. An EUS-FNA was performed and the cytologic material obtained was used for routine cytologic smears and one cell-block. Results: The rapid-HE stained smears showed loose clusters and single cells with finely granular cytoplasm and hyperchromatic nuclei with fine chromatin, resembling neuroendocrine cells, with minimal to moderate atypia, insufficient for diagnosis. The cell-block cellular material revealed a solid pattern with thin vessels throughout, scattered rosette-like or intact papillary structures with fibrovascular components. The cells were displayed in a perivascular fashion. In one case, we also identified fragments of liver tissue and gastric mucosa with normal architecture. Positive immnunohistochemistry reactions for beta-catenin, CD56, androgen-receptor, vimentin and negative reactions for E-cadherin, AE1/AE3 and chromogranin confirmed the diagnosis of a solid pseudopapillary pancreatic neoplasm (SPN). Conclusion: SPN is a rare entity, comprising less than 2.7% of all pancreatic tumours. It mainly affects young women and the common location is the tail of the pancreas. In the reported cases, presentation and cytology appearance weren’t conclusive for this pathology. The aid of a cell-block procedure lead to the correct diagnosis, giving the possibility of immunohistochemistry tests and haematoxylin-eosin staining equivalent to histological slides. E-PS-07-013 A rare case of primary inferior vena cava leiomyosarcoma mimicking hepatocellular carcinoma presentation O. Neagu 1 , M. Grasu 2 , M. Dumbrava 2 , R. Cerban 2 , V. Herlea 2 , G. Becheanu 2,3 1 University Emergency Hospital Bucharest, Romania, 2 Fundeni Clinical Institute Bucharest, Romania, 3 "Victor Babes" National Institute of Pathology, Bucharest, Romania Background & Objectives: Primary leiomyosarcoma of the inferior vena cava (IVC) is a rare malignant tumour, with less than 400 cases reported so far. It has a slow progression and becomes symptomatic at an advanced stage, justifying its poor prognosis once detected. Clinical presentation depends on tumour location along the IVC, divided into three segments by Kulaylat. Methods: We report a case of a 61-year-old male, diagnosed 6 months prior with an IVC thrombosis, who was admitted for a liver tumour evaluation. CT examination revealed a 65/50 mm tumour, involving the VI-VII segments, the IVC and the abutting right atrial wall. Another similar small lesions were also noted in the right lobe, highly suggesting a hepatocellular carcinoma. Results: The liver biopsy showed a spindle cell proliferation with eosinophilic fibrillary cytoplasm and large pleomorphic nuclei with scattered atypical mitoses. Ancillary immunohistochemistry tests showed positive tumour cells reactions for smooth muscle markers (SMA, desmin, H-caldesmon) and negative reaction for CD117, DOG1 and CD34, advocating for a leiomyosarcoma. Thoroughly systemic investigation didn’t find any other conceivable primary site for the liver tumour. Considering the aforementioned findings, the conclusive diagnosis was a leiomyosarcoma of the third segment of the IVC with extra- and intraluminal growth. Conclusion: Although IVC leiomyosarcoma is more common among women and usually affects the first two segments, the presentation herein was distinctive. The mainstay treatment is complete surgical resection with a customized approach. Given the tumour extension in our reported case, a palliative chemotherapy scheme is currently administered, with no tumour progression so far. E-PS-07-014 Solid and pseudopapillary neoplasm of the pancreas: pathological characteristics of 5 cases with Imaging correlation A. Bdioui Thabet 1 , A. Fourati 2 , N. Mhammedi 3 , S. Benkhlifa 3 , M. Mokni 3 1 Georges Pompido Hospital Paris, France, 2 Sahloul Hospital of Sousse, Tunisia, 3 Farhat Hached Hospital of Sousse, Tunisia Background & Objectives: Solid pseudopapillary neoplasm of the pancreas is a rare tumour often detected initially on imaging. Of uncertain histogenesis, it has a low-grade malignant potential with excellent post-surgical curative rates and rare metastasis. Pathological evaluation remains the gold standard in reaching a definitive diagnosis. On morphology alone, other primary pancreatic tumours pose a diagnostic challenge. Recent advances in immunohistochemical characterization have made the histopathologic diagnosis more specific and, shed light on the likely histogenesis of this rare tumour. Results: 5 patients included 4 females and 1 male, with a median age of 48.5 years. CT scan was performed showed a pancreatic well limited mass measuring between 4 and 17 cm. A peripheral capsule was seen and some calcifications were detected and none of the patients was found to have hepatic and lymph nodes metastases. In one case an hemorrhagic content was noticed. Microscopic examination and the immunohistochemestry study confirmed the diagnosis of solid pseudopapillary neoplasm in all cases. E-PS-07-015 Hepatocellular adenomas in a cirrhotic liver: report of an unusual case C. Araújo 1 , J. Cristóvão 2 , A. Figueiredo 3 , A. Carvalho 4 1 Centro Hospitalar Universitário Lisboa Central, Portugal, 2 NOVA Medical School, Lisboa, Portugal, 3 Serviço de Anatomia Patológica - Hospital Curry Cabral, Centro Hospitalar e Universitário de Lisboa Central, E.P.E., Portugal, 4 Hospital Curry Cabral, Centro Hospitalar Universitário Lisboa Central, Portugal Background & Objectives: Hepatocellular adenoma (HCA) is a liver tumour usually presenting in young females undergoing oral contraception. HCA occurs mostly against the background of healthy and disease free liver. Herein, we report a case of a 73-year-old male patient with multiple HCA-like lesions in the setting of a cirrhotic liver. Methods: A 73-year-old male with a past history of arterial hypertension, dyslipidemia, type 2 diabetes mellitus and oesophageal varices was investigated for anemia and cholestasis and performed a computed tomography that revealed four nodules in the IV and V hepatic segments, the largest one with 4cm. Results: The liver biopsy showed a cirrhotic liver, but the definite diagnosis of the hepatic nodules was not possible. The patient was submitted to a hepatic bissegmentectomy. Histology revealed nodules of hepatocellular proliferation with preserved reticulin framework, normal thickness of the trabeculae, unaccompanied arteries and absence of portal tracts. CD34 expression was patchy, glutamine synthetase confined to perivenular hepatocytes and no nuclear expression of beta-catenine , p53 or HSP70. The final diagnosis was compatible with hepatocellular adenoma-like nodules in a background of cirrhosis with features of steatohepatitis. A close follow-up of the patient was recommended. Conclusion: Nodules that deviate in appearance, size and behavior from the conventional spectrum of large regenerative nodules, dysplastic nodules and hepatocellular carcinoma in cirrhotic livers are very rare and only a handful of cases of HCA in the background of cirrhosis have been described. Despite this, this possibility needs to be considered, in order to avoid the risk of misdiagnosing and subjecting patients to incorrect treatments. Extensive sampling and immunohistochemistry are fundamental to achieve a correct diagnosis. E-PS-07-016 Foregut origin ciliated cyst of the gallbladder H. Dincer 1 , E. Yarıkkaya 1 , N. Dursun 2 1 University of Health Sciences, Department of Pathology, Turkey, 2 University of Health Sciences, Istanbul Health Practice and Research Hospital, Department of Pathology, Turkey Background & Objectives: Foregut origin ciliated cysts of the gallbladder are very rare, benign, cystic lesions. They are usually located above the diaphragm but they can also arise in relation to the liver, gallbladder and pancreas. Methods: A 62-year-old women was referred to our hospital’s surgery clinic with symptoms of chronic abdominal pain. On abdominal ultrasonography and computed tomography, multiple calculi was found. The gallbladder was resected through laparoscopic cholecystectomy. Results: Grossly, the cystic lesion, measuring 0,6x0,6x0,3 cm, was located in the neck of the gallbladder. The cyst had no communication with the lumen. Microscopically the histopatology showed that the cyst was lined by pseudostratified ciliated columnar epithelium. These findings led us to diagnosis of ciliated foregut cyst. Conclusion: Ciliated foregut cysts are rare anomalies due to aberrant embryological development. Characteristically, most of the cases are middle-aged females and unilocular lesions. Ultrasound is an efficient method of imaging for hepatobiliary masses. There are a few reports of squamous cell carcinoma arising in the ciliated foregut cyst, however there is no reports in the gallbladder. Foregut cysts requires surgical removal because of the frequent occurrence of squamous metaplasia and possibility of squamous cell carcinoma. E-PS-07-017 Inflammatory myofibroblastic tumour of the pancreas - case report R. Gajanin 1 , V. Gajanin 1 , I. Sladojević 1 , M. Cuk 2 1 University of Banja Luka, Faculty of Medicine, Bosnia and Herzegovina, 2 University of East Sarajevo, Faculty of Medicine, Bosnia and Herzegovina Background & Objectives: Inflammatory myofibroblastic tumours (IMT) are rare mesenchymal proliferative lesions, built of myofibroblasts and inflammatory cell infiltrate in the stroma, of unknown etiology and prognosis. They can be found in all anatomical regions, most commonly in the lungs, and very rarely in the pancreas. Methods: We report a case of a 51 years old woman with IMT localized in the pancreatic head. Clinical manifestations included abdominal pain, nausea, yellowing of the skin and mucous membranes, and newly diagnosed diabetes. Using MRCP, we saw a dilatation of the intrahepatic and extrahepatic bile ducts and a soft tissue change with unclear boundaries, localized in the pancreatic head, 9 cm in diameter. The surgical treatment included pancreatectomy and splenectomy. Results: Macroscopically, the tumour change was located in the pancreatic head, had a yellow-whitish color, sized 9.5 x 4.5cm. Morphologically, it was built by spindle cells with storiform and fascicular arrangements and mixed stromal inflammatory infiltrate. Immunohistochemical analysis showed positive staining for SMA, Calponin, Desmin, and ALK, and negative for Myogenin, S-100, H Caldesmon, and CD117. The diagnosis of IMT in the pancreas with peripancreatic extension in the connective tissue was established, with negative resection margins. The patient is 18 months without recurrence of the disease. Conclusion: IMT is rare in the pancreas. So far, 32 cases were published in the English language literature. Presurgical differentiation from other neoplastic lesions is difficult and usually requires resection and histological analysis. Morphologically, it is necessary to differentiate IMT from fibrosarcoma, adenocarcinoma, lymphoma and chronic pancreatitis. E-PS-07-018 Mixed adenocarcinoma and neuroendocrine carcinoma of the gallbladder: next generation sequencing suggests a monoclonal origin F.M. Sta. Ines 1 , A.L. Anceno 1 , R.A. Salamat 1 , N. Navarro Jr. 1 , G.L. Pua 1 , J.J. Andal 1 , D. Ang 1 1 St. Luke's Medical Center, Philippines Background & Objectives: Mixed adenoneuroendocrine carcinoma (MANEC) of the gallbladder is a rare tumour that is defined by the presence of a neuroendocrine carcinoma or neuroendocrine tumour, admixed with an adenocarcinoma, each component constituting at least 30% of the neoplasm. MANEC's histogenic classification remains unclear. We present a case of a 74 year-old Filipino woman who presented with right upper abdominal pain and fever. Whole abdominal CT scan demonstrated a distended multiseptate gallbladder and a 1.1 cm. non-enhancing faintly hyperdense ovoid focus ( suggestive of cholelithiasis versus sludgeball ) within the body. She subsequently underwent open cholecystectomy. Methods: Histopathologic examination of the cholecystectomy specimen revealed two morphologic and immunophenotypic components: a mixed well-differentiated adenocarcinoma (30%) and a poorly differentiated large cell neuroendocrine carcinoma (70%). The adenocarcinoma and neuroendocrine tumour components were carefully microdissected separately, and next-generation analysis was performed on both components, using Illumina Trusight 15 Tumour (TST) kit and sequenced on Illumina MiSeq. Results: The tumour showed a high mitotic rate of 83 mitosis per 10 high power fields and extensive necrosis. Immunohistochemical studies showed the neuroendocrine component to be reactive to synaptophysin and chromogranin. Mutational analysis of selected targeted regions of 15 cancer associated genes identified a TP53 missense mutation that leads to a stop codon (c.273G>A, p.Trp91Ter) in both components. Conclusion: The molecular genetic similarities of the two morphologically different components of the tumour supports the hypothesis that MANEC arises from a common precursor stem cell capable of divergent phenotypic differentiation. E-PS-07-019 Splenic vein leiomyosarcoma: a case report F. Filipello 1 , G. Fiorentini 2 , C. Doglioni 3,1 , M. Schiavo Lena 3 1 Vita-Salute San Raffaele University, Milan, Italy, 2 Pancreatic Surgery Division, IRCCS San Raffaele Hospital, Milan, Italy, 3 Pathology Unit, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, Milan, Italy Background & Objectives: Leiomyosarcoma (LMS) is an aggressive mesenchymal tumour originating from smooth muscle. Primary pancreatic LMS has been reported in the literature, nevertheless it is a rare entity. Venous origin for LMS is an extremely uncommon site of origin of LMS, mostly affecting the inferior vena cava and only five cases arising from the splenic vein have been described. We present a case of primary splenic vein LMS. Methods: We report the case of a 51 year-old women who presented to San Raffaele Scientific Institute with non-specific abdominal pain. Abdominal computed tomography showed a 27x15 mm solid tumour in the body of the pancreas, in proximity to the splenic vein. Afterward, the patient underwent ecoendoscopy with cytological examination that indicated the mesenchymal nature of the lesion. Distal pancreatectomy and splenectomy were performed and subsequent histopathological examination. Results: Morphological and immunohistochemical investigations showed a moderately differentiated LMS originating from the splenic vein, infiltrating the pancreatic parenchyma with three lymph nodes involved by contiguity. Conclusion: Venous splenic LMS is a rare entity, nevertheless it can be a difficult differential diagnosis from other pancreatic mesenchymal tumours. In order to make a correct diagnosis, care must be taken for the anatomical localization of the tumour from early diagnostic steps. Careful macroscopic evaluation and exhaustive sampling are fundamental to identify the structure of origin, to be confirmed microscopically. E-PS-07-020 Acinar cell cystadenoma of the pancreas G. Setdikova 1 , O. Paklina 1 , A. Karpov 1 , M. Tavobilov 1 1 Botkin Clinical Hospital, Russia Background & Objectives: Acinar cell cystadenoma is a rare, benign cystic lesion of the pancreas that can affect almost any age group. First described in 2000 by Klöppel using the term acinar cell cystic transformation, the term acinar cell cystadenoma was first proposed by Albores-Saavedra, as the lesion was postulated to be the benign precursor of acinar cell cystadenocarcinoma. Methods: We present a case of acinar cell cystadenoma in a 67-th men. Results: A 67-year-old man was admitted to our hospital complaining of abdominal distension. He had no history of alcohol intake, acute pancreatitis, or trauma. Serum carbohydrate antigen (CA) 19.9 and carcinoembryonic antigen (CEA) was normal. Computed tomography (CT) showed a cystic mass with an irregularly thickened wall of up to 43 mm. No pancreatic duct dilatation or peripancreatic inammatory changes were identied. Enucleation was remarkable for a 40 mm pussy uid-lled, thin-walled, unilocular cyst. The cyst was lined by a single layer of cuboidal to columnar cells, with uniform, round nuclei with occasional small nucleoli and eosinophilic, granular cytoplasm, which formed small acinar structure with eosinophilic PAS-positive cytoplasmic granules. The cyst wall was collagenous with no evidence of ovarian-type stroma. Immunohistochemical stains showed the cyst-lining cells were trypsin and chymotrypsin, Muc6 positive. These findings confirmed the cytological diagnosis of an acinar cell cystadenoma. Conclusion: We report an unusual case of a cystic lesion of the pancreas lined by acinar cells with mucinous metaplasia, consistent with the diagnosis of acinar cell cystadenoma. Acinar cell carcinoma is an uncommon malignant tumour accounting for 1% to 2% of all exocrine pancreatic neoplasms. This lesion can be added to the list of unilocular cystic neoplasms of the pancreas. E-PS-07-021 Cystic neuroendocrine tumour of the pancreas: a misleading variant D. Chiba 1 , S. Chaieb 2 , S. Mestiri 2 , O. Belkacem 2 , S. Yacoub 2 , N. Abdessayed 2 , B. Sriha 2 , M. Mokni 2 1 Department of Pathology Farhat Hached Hospital, Tunisia, 2 Farhat Hached Hospital, Tunisia Background & Objectives: Pancreatic neuroendocrine tumours (PanNETs) are rare neoplasms that comprise up to 5% of pancreatic malignancies. Cystic PanNETs are a distinctive subgroup with unique clinical and pathological features. Because of their cystic nature, preoperative radiological diagnosis of this entity continues to be a challenge to differentiate them from others pancreatic lesions like cystic neoplasms. The clinical and histopathologic characteristics of cystic PanNETs are poorly defined which motivated us to present this case report. Methods: We present a 54-year-old man with no significant history in whom we found incidentally a tumour in the tail of the pancreas, by abdominal ultrasonography. Computed tomography revealed a well-defined cystic lesion in the tail of pancreas measuring 45 mm of diameter. A mucinous cystic lesion was suspected and considering the malignat potential of this tumour, the patient had a distal pancreatectomy without prior cytological diagnosis. Results: Macroscopically, the surgical specimen was constituted of a distal pancreatectomy measuring 10 X 6cm, containing on cut section a multilocular cystic mass with a hemorrhagic content. A definite diagnosis of neuroendocrine neoplasm was confirmed by microscopic and immunohistochemical findings using synaptophysin , chromogranin. Grading of the tumour was based on mitotic index and ki67, and the tumour was classified according to the ENETS2010/OMS 2017, as G1 well differentiated neuroendocrine tumour with cystic component. Conclusion: Cystic PanNETs are a distinctive subgroup of PanNETs with unique clinical and pathologic features. Because of their cystic nature, these neoplasms often present a radiologic preoperative diagnostic dilemma. Recently, endoscopic ultrasonography guided fine needle aspiration (EUS-FNA) was reported to be useful for preoperative definitive diagnosis. But until now; the definitive diagnosis remains only histological reinforced by immunohistochemistry. E-PS-07-022 Intestinal immunophenotype in pancreatic cancer: true or fall? G. Setdikova 1 , O. Paklina 1 1 Botkin Clinical hospital, Russia Background & Objectives: To study the immunophenotype ducts of the pancreas in embryogenesis and taking into account the data obtained to analyse the immunophenotype of pancreatic ductal adenocarcinoma. Methods: We examined the expression of MUC1, 2,5AC, CK8, CK7, CK20, CDX2 by immunohistochemical analyses in pancreas ducts at different weeks of gestations (fron 6 to 21 weeks). Results: At 3-7 weeks in pancreas the expression of PanCK, CK7, CK20, CDX2 and MUC1,2,5АС types was negative. We found only expression CK8 in foregut epithelium. At 13-14 weeks we found expression CK20 in goblet cells and epithelial cells of the foregut epithelium. At 20-21 weeks for the first time, we found the cytoplasmic expression with CK7 and MUC1 in the epithelium of the pancreatic ducts, which may indicate the onset of specialization. Expression of CK 20 was found not only in the goblet cells, but throughout the entire foregut epithelium. Conclusion: Pancreatobiliary type of epithelium is more specialized. Substrate for the development of the pancreas is the foregut epithelium , which at the embryogenesis, differentiates into specialized organs and tissues; Based on this statement and comparing the available morphological data in PDA with intestinal immunophenotype, we found only incomplete intestinal metaplasia of the epithelium can be asserted, leading to further development of cancer, but not the appearance of true intestinal differentiation of the tumour. E-PS-07-023 Comparison of the results of the calculation of the liver volume of cadavers on the basis of linear dimensions obtained with sonography and measurements ex vivo I. Stepanyan 1 , V. Izranov 2 , S. Stepanyan 2 , K. Abdujabborov 2 , M. Shushval 2 , V. Gordova 2 1 Baltic Federal University; Infectious Diseases Hospital of the Kaliningrad region, Russia, 2 Baltic Federal University, Russia Background & Objectives: We set a goal to find out whether the three linear liver sizes used in formula J.T.Childs are sufficient to get an objective parameter of an organ volume before and after its dissection from the abdominal cavity. Methods: Liver sonography was performed before an autopsy with measurements of the anteroposterior (AP) of the left and right lobes and oblique vertical size (OVS) of the right lobe. The left lobe was measured without view of the inferior vena cavae, the right lobe from the anterior axillary line (AAL) and the midclavicular line (MCL). The similar to sonography sizes of both lobes were measured by a ruler on the dissected liver. The linear dimensions obtained from sonography and dissection results were substituted into the J.T. Childs formula. Results: After dissection the liver from the abdominal cavity, the average linear dimensions significantly change: AP size of the left lobe decreases 2.27 times, AP size of the right lobe decrease 1.9 times, OVS of the right lobe increases 1.15 times. Due to changes in linear dimensions, the volume is according to the formula J.T.Childs after liver dissection from cadavers, decreases 2.2-2.3 times (p≤ 0.05). Conclusion: With a direct dependence of the volume of the liver on the above dimensions, they are not enough to obtain an objective parameter. It is required either to add additional linear dimensins to the formula or to introduce a non-linear correlation coefficient of these linear dimensions. E-PS-07-024 The dependence of the results of the calculation of the volume of the liver according to the formula J.T.Childs on the choice of access points and depth of breathing I. Stepanyan 1 , V. Izranov 2 , V. Gordova 2 , M. Beleckaya 2 , S. Stepanyan 2 1 Baltic Federal University; Infectious Diseases Hospital of the Kaliningrad Region, Russia, 2 Baltic Federal University, Russia Background & Objectives: We noticed that the linear dimensions of the liver depend on the access points and the depth of breathing. Study objective is to determine the effect of these parameters in an ultrasound study on the volume of the liver, calculated according to the formula J.T. Childs. Methods: The measurements of the left and right lobe carried out by two ultrasound diagnostics doctors on 26 healthy volunteers with quiet breathing and with a breath hold on a deep breath, for the left lobe with and without an inferior vena cava (IVC) in sight, for the right lobe from access via the anterior axillary line (AAL) and midclavicular line (MCL). The volume of the liver was calculated by the formula J.T.Childs: 343.71+0.84*(oblique vertical size (OVS)*anterior-posterior (AP) of the right lobe*anterior-posterior(AP) of the left lobe) / 1000. Results: The maximum sizes of the volumes of the liver are obtained with quiet breathing without capture in the field of view of the IVC for left lobe, and at the level of AAL and MCL for the right liver lobe, the average values are comparable (p ≤ 0.05). Conclusion: To obtain objective resultes of possible calculations of the liver volume by different specialists, we recommended measuring the linear dimensions of the liver with quiet breathing, when measuring the left lobe without IVC in view, when measuring the right lobe of AAL of MCL. E-PS-07-025 Hepatitis C: the importance of non-invasive diagnostic methods in the development of liver fibrosis I. Stepanyan 1 , V. Izranov 2 , S. Stepanyan 2 , I. Ashtarkhanova 2 , V. Gordova 2 , I. Ivanov 1 , E. Konopleva 2 1 Baltic Federal University; Infectious Diseases Hospital of the Kaliningrad Region, Russia, 2 Baltic Federal University, Russia Background & Objectives: Liver fibrosis is the inevitable outcome of hepatitis C and detecting it in the early stages makes it possible to adjust the therapy in such a way as to improve the quality and increase the life expectancy of the patient. It is important to understand how much the changes in elastometry and blood tests of patients are proportional to the stages of development of fibrosis. Methods: The results of liver 2D SWE (shear wave) elastometry on the Aixplorer (France) and the results of blood tests (indices Aspartate aminotransferase to platelete ratio (APRI) and Fibrosis-4 (FIB-4)), were compared in 56 patients with hepatitis C. Results: The results of the liver 2D SWE elastometry with the assessment of the stage of fibrosis according to the conventional Metavir scale showed that 25 patients had 0-1 fibrosis stage; 11 patients had stage 1-2; 7 patients had stage 2-3; and 13 patients had stage 3-4, respectively. At the same time, with fibrosis of the 0-1 and 1-2 stages, no changes in blood parametes (APRI and FIB-4) were observed. Conclusion: Comparison of the results of 2D SWE elastometry with the results of laboratory blood tests show that elastometry reveals fibrosis with 0-1 stage, and methods APRI and FIB-4 starting from 2-3 stages. Therefore, 2D SWE elastometry is a more sensitive method for diagnosing fibrosis in its early stages than APRI and FIB-4 in hepatitis C. E-PS-07-026 Detection of human polyomavirus 6 and 7 in the human cholangiocarcinoma tissues F. Klufah 1 , E. Chteinberg 2 , G. Mobaraki 1 , R.A. Alharbi 3 , A.K. Kurz 4 , V. Winnepenninckx 2 , E. Speel 2 , A. zur Hausen 2 1 Department of Pathology, Maastricht University Medical Center, The Netherlands, 2 Maastricht University Medical Centre+, The Netherlands, 3 Faculty of Applied Medical Sciences, Albaha University, Saudi Arabia, 4 University Hospital RWTH Aachen, Germany Background & Objectives: Cholangiocarcinoma (CCA) is a rare biliary duct neoplasm with poor prognosis. Recently, the presence of HPyV6 has been reported in the bile hepatobiliary diseases including the bile of CCA patients. Here, we investigated the prevalence of HPyV 6 and 7 in CCA by using diverse molecular techniques to assess their possible role in neoplastic hepatobiliary diseases. Methods: We tested 61 FFPE tissues of 21 CCA patients. PCR screening for HPyVs were conducted using a pair of degenerated HPyV primers. Specific-PCRs for HPyV6 and 7 and MCPyV were performed. All PCR products were sequenced. FISH, RNA(ISH) and immunohistochemistry (IHC) were used to assess the presence of HPyV6 and 7 on the DNA, transcriptional and transitional level. Results: Degenerated primers revealed the presence of HPyV7 in 4 out of 21 CCAs (19%) and HPyV6 in 2 CCAs (9.5%). The presence of HPyV7 and 6 DNA was confirmed by specific FISH. RNA-ISH confirmed the presence HPyV6 and 7 on the single cell level. IHC using monoclonal antibodies (HPyV7 2T10 and HPyV6 1T1, both kindly supplied by Dr. C. Buck, NCI, Bethesda, USA) revealed the specific nuclear expression of viral proteins within these tissues. Conclusion: HPyV6 and 7 are hepatotropic and can be specifically found in peritumoural non-neoplastic hepatocytes and to a lesser extent in neoplastic CCA cells. In our patient cohort, HPyV7 was found to be more prevalent than HPyV6. Based on our results, HPyV6 and 7 are yet unlikely to play an important role in the etiopathogenesis of CCA. E-PS-07-027 Solid-pseudopapillary neoplasm of the pancreas: a (not so) rare diagnosis C. Alves-Vale 1 , R. Brodbeck Ilgenfritz 1 , P. Borralho 1 1 CUF Descobertas Hospital, Department of Pathology, Lisbon, Portugal Background & Objectives: Solid-pseudopapillary neoplasm (SPN) is an extremely rare entity, corresponding to 0.9-2.7% of all exocrine pancreatic tumours, mostly affecting young women. We aimed to review the clinical and histopathological features of the SPNs diagnosed in our department. Methods: This retrospective analysis collected all cases of SPN diagnosed between January 2009 and March 2019. Clinicopathological data was analysed. Results: The diagnosis of SPN was made in four patients: one after fine-needle aspiration and three after surgery, corresponding to 5.1% (3/59) of all surgically resected pancreatic neoplasms in our institution. The group includes one male and three female patients, with a mean age of 36.5 years (SD±14.7). The three patients undergoing surgery in our hospital presented with a single mass located in the pancreatic tail, with a mean size of 105.0 mm (SD±20.0). The lesion was associated with nausea in one patient and it was incidentally found in imaging studies in the remaining two cases. Gross examination revealed an encapsulated lesion, with both solid and/or cystic components. Microscopic analysis showed solid areas and pseudopapillae covered by epithelial cells positive for beta-catenin, CD56, CD10 and vimentin. Complete excision of the lesion was achieved in all cases. No evidence of relapse has been detected (follow-up period: 3 months-6 years). Conclusion: A correct morphological analysis supported by ancillary studies allows the diagnosis of SPN. Our series adds to the list of this singular entity while reminding us of its possibility in male patients. E-PS-07-028 Mature cystic teratoma of the liver: a case report M. Varela dos Santos 1 , A. Figueiredo 2 1 Serviço de Anatomia Patológica - Centro Hospitalar e Universitário de Lisboa Central, E.P.E., Portugal, 2 Serviço de Anatomia Patológica - Hospital Curry Cabral, Centro Hospitalar e Universitário de Lisboa Central, E.P.E., Portugal Background & Objectives: Teratomas are germ cells tumours, which must contain more than one of the three germ layers: ectoderm, endoderm and mesoderm. They are usually located on the ovaries and testis. Liver teratomas are extremely rare and comprise less than 1% of all teratomas. Pathological diagnosis is crucial to confirm radiological suspicion along with the assessment of immature component, which has implications in further management of these patients. Methods: The present study is a case report of a liver teratoma in an adult, diagnosed and treated in 2019. A 27-year-old woman, with no relevant prior medical history, was admitted in our Medical Centre in March 2019 after the incidental discovery of a hepatic lesion on a CT-scan: there were distinctive imaging characteristics suggesting liver teratoma, and based on this information the patient was electively submitted to a mesohepatectomy for the centrally located hepatic lesion. Results: Gross pathological examination showed a cystic tumour with 21cm: cut section revealed multiple cystic areas with sebaceous material, hair and calcifications. Microscopic examination showed a mixture of various tissues, including skin and appendages, bone, adipose tissue and respiratory epithelium: the final diagnosis was Mature Liver Teratoma, fully resected. The patient had a gradual post-operative recovery phase without major complications and was discharged after 9 days of hospitalisation. 2- and 4-weeks follow-up confirmed absence of symptoms and a full recovery. Conclusion: Liver Teratomas are extremely rare, even more in adults, with only a small number of cases described in the literature. Albeit they harbour some extremely distinctive imagiological features, pathological examination is vital to the correct diagnosis and characterization of teratomas. Complete resection of the lesion remains, to this day, the best treatment option. E-PS-07-029 Unique cystic neoplasm of liver in child-undifferentiated embryonal sarcoma Z. Yusifli 1 , M. Kazimi 1 , K. Beydullayev 1 1 Central Customs Hospital, Azerbaijan Background & Objectives: Undifferentiated embryonal sarcoma of the liver (UESL) is a unique and rare malignant mesenchymal neoplasm. We report a case of UESL observed in a 14 year old boy. The patient underwent liver resection for cyst hydatid. The intraoperative frozen section technique was used during operation and was reported as fibrinous tissue, no malignancy. Grossly 14 x 11cm encapsulated mass were seen in liver parenchyma. The cut surface was soft with necrosis and haemorrhage areas. Methods: Specimens were fixed in 10% formalin solution and embedded in paraffin. Sections were stained with Haematoxylin eosin and special immunohistochemical stains. Staining was considered positive when >10% of cells showed positive staining with appropriate pattern. Results: Microscopic examination showed tumour with hypocellular and myxoid stroma. In some areas tumour was highly cellular with marked pleomorphism. Bizarre hyperchromatic giant cells, cytoplasmic hyaline eosinophilic globules and entrapped benign bile ducts were present. Immunohistochemical staining showed positivity for CD56, desmin, SMA, CD68 and were negative for pan-cytokeratin, Heppar-1. The MIB - 1 proliferation index was 20-25% in neoplastic cells. Based on these findings, a diagnosis of UESL was confirmed. Conclusion: UESL is a rare and aggressive mesenchymal neoplasm which occurs almost exclusively in children and adolescents. Intraoperative frozen sections technique is not usefull, because cysts, necrosis and haemorrage areas may occupy up to 80-90% of the cut surface. Early correct diagnosis and complete resection are necessary for a favorable outcome. This entity should keep in mind in all cystic liver masses in children. E-PS-07-030 Cystic lymphangioma in pancreas M. Chantziara 1 , D. Mpouklas 1 , G. Theodoropoulou 1 , S. Roditis 2 , X. Grammatoglou 1 , A. Kostopoulou 1 , I. Margaris 3 , T. Choreftaki 1 1 Department of Surgical Pathology/General Hospital of Athens, "G.Gennimatas", Greece, 2 3rd Department of Surgery/General Hospital of Athens "G. Gennimatas", Greece, 3 2nd Department of Surgery/General Hospital of Athens "G. Gennimatas", Greece Background & Objectives: We present the case of a 50-year-old male patient with cystic lymphangioma in pancreas. Methods: The patient presented to the surgery department complaining of atypical abdominal pain the last six months. An abdominal computerized tomography (CT) scan was performed and a cystic neoplasm with a maximum diameter of 18.6 cm was seen at the pancreatic body and tail. The mass had not invaded any adjacent organs. The lesion was aspirated using the EUS-FNA needle. Cytology felt to be consistent with the diagnosis of pancreatic serous cystadenoma. The patient underwent peripheral pancreatectomy and spleenectomy. Results: On gross sectioning, the cystic neoplasm had a honeycomb appearance with single space filled with haemorrhagic yellowish fluid. Microscopic examination revealed cystic lesions of variable size, separated by fibroconnective septa, containing irregular smooth muscle fascicles, adipocytes and mature lymphocytes. These cystic spaces were lined by flattened and slightly elevated endothelial cells. No cell atypia was found. Immunohistochemistry (IHC) labeling for endothelial markers, factor VIII-R antigen and CD 31 was positive while CD 34 was focally weakly positive. Furthermore, immunohistochemistry for Inhibin-a, EMA, CK19, CKAE1/AE3, MUC-1 was negative. So, the diagnosis of pancreatic lymphangioma was made. Conclusion: Cystic lymphangioma of the pancreas is extremely rare, accounting for less than 1% of pancreatic tumours but should be taken into consideration as a differential diagnosis of a pancreatic cystic lesion. E-PS-07-031 Adenosquamous carcinoma of the ampulla of Vater: report of two cases M.E. Kara 1 , E. Uzun 1 1 Gaziantep University Medical Faculty Hospital, Department of Pathology, Turkey Background & Objectives: Primary adenosquamous carcinoma of the ampulla of Vater is rare. There are few reports about its clinicopathological features. Here, we report two adenosquamous carcinomas of the ampulla of Vater. Methods: CASE 1 A 62 years-old male presented with abdominal pain and jaundice. The laboratory examination revealed alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), amylase and total bilirubin levels elevated. CA 19-9 level was 242 U/mL. Computed tomography (CT) revealed a solid mass in the periampullary region. Pancreatoduodenectomy was performed to the patient. Grossly infiltrative, solid mass, measuring 4.2x3x3 cm, was detected in the ampulla of Vater. Histopathologically; the tumour was comprised both of adenocarcinoma and squamous cell carcinoma elements. The retroperitoneal margin was involved, pancreas invasion and lymph node metastasis were present. The patient has received chemoradiotherapy and had no tumour recurrence or metastasis until 48 months after surgery. Results: CASE 2 A 49 years-old female patient presented with abdominal pain and jaundice. The laboratory examination revealed ALT, AST, LDH, gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), amylase and total bilirubin levels elevated. CA 19-9 level was 560 U/mL. Computed tomography revealed a solid mass in the periampullary region. Whipple procedure was performed. Grossly; solid mass, measuring 2.5x1.5 cm, was observed in the ampulla of Vater. Duodenum wall was involved by tumour. Microscopic examination revealed that the tumour comprised both adenocarcinoma and squamous cell carcinoma components. The patient has received chemoradiotherapy and had no tumour recurrence or metastasis until 25 months after surgery. Conclusion: Adenosquamous carcinoma is defined as a tumour which has both adenocarcinoma and squamous cell carcinoma components. Its histogenesis is not clear. While it has been reported in the oesophagus, stomach, small intestine and colorectum, rare in the ampulla of Vater. E-PS-07-032 Ductal adenocarcinoma of the pancreas with extensive hyaline globules: a case report M.E. Kara 1 , E. Uzun 1 1 Gaziantep University Medical Faculty Hospital, Department of Pathology, Turkey Background & Objectives: Ductal adenocarcinoma is the most common type of pancreatic cancer (constitutes %90 of all pancreas cancers) and it is a type of exocrine pancreatic cancer. In the world; ductal adenocarcinoma of the pancreas is the fourth most common cause of death from cancer in both men and women. Early recognition of these precursor lesions is important to improve the treatment and prognosis of PDAC. Methods: Case report: A 58 years old female patient was presented with weight loss and fever. Laboratory examination revealed that alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT) and amylase levels were elevated. CA19-9 level was 896 U/mL. Contrast-enhanced computed tomography (CT) revealed a solid mass in the head of the pancreas, measuring 25x20 mm. Pancreatoduodenectomy was performed. Grossly; the infiltrative, solid tumour was detected in the head of the pancreas which was infiltrating duodenal wall. Results: Histologically; tumour had ductal adenocarcinoma morphology with extensive hyaline globules. Immunohistochemically; the tumour was positive with CK7, CK19, MUC1, MUC5, and Maspin. Lymph node metastasis, lymphovascular and perineural invasion were present. Margins were uninvolved. After surgery patient is receiving chemoradiotherapy for 2 months. Conclusion: Hyaline globules in the pancreas are usually seen in solid pseudopapillary carcinomas. While Neuroendocrine carcinomas can also have hyaline globules focally, it is uncommon in ductal adenocarcinomas. Because of its rarity; there is no data about the meaning of hyaline globules in pancreatic ductal adenocarcinomas. E-PS-07-033 Unusual localisations of hydatid cyst and its clinicopathological features M.E. Kara 1 , E. Uzun 1 1 Gaziantep University Medical Faculty Hospital, Department of Pathology, Turkey Background & Objectives: Hydatid cyst is a zoonotic parasitic disease caused by Echinococcus granulosus larva. It is endemic in Turkey and is a big health problem in farming areas. The hydatic cyst is mostly seen in the liver and lung, it can rarely occur in atypical localizations. Methods: In this study 550 hydatid cysts which were diagnosed in Gaziantep University Medical Faculty Hospital between 2012-2019, were evaluated based on criteria such as sex, age, cyst localization, liver or lung involvement for atypical localized cysts, Echinococcus granulosus indirect hemagglutination antigen (IHA) test status. Results: 232 of (%42.2) 550 cyst hydatids were localized in lung, while 231 (%42) were in liver. 87 of 550 cyst hydatids were localized outside of liver and lung. 16 of these cysts were in the kidney, 13 were intraabdominal, 13 were in the spleen, 9 were in the heart, 7 were in the brain, 2 were in the ovary, 1 was in the pancreas, 1 was in diapraghm, 1 was in the gallbladder and 23 were in the musculoskeletal system. 24 of (%27,5) 87 unusually localized cyst hydatids showed lung or liver involvement. Right lower lobe and left upper lobe were most involved lobes by cyst hydatid at 39% and 25%, respectively. Conclusion: Although its typical localizations are liver and lung, hydatid cyst can be seen in unexpected organs/tissues. It should be evaluated in differential diagnosis because of its tumour mimicry in imaging studies. E-PS-07-034 Pancreatic mixed neuroendocrine- nonneuroendocrine neoplasm: a case report S. Batur 1 , î Kutlu 1 , K. Ozcan 1 , G. Ozcan 1 , N. Kepil 1 , T. Ozturk 1 1 Istanbul University Cerrahpasa-Cerrahpasa Medical Faculty Department of Pathology, Turkey Background & Objectives: The WHO classification of the tumours of endocrine organs, published 2017, has introduced significant changes in the classification of pancreatic neuroendocrine tumours. The previous term mixed adeno-neuroendocrine carcinoma (MANEC) is substituted by the term mixed neuroendocrine-non neuroendocrine neoplasm (MiNEN). MiNEN are neoplasms with two distinct neuroendocrine and non-neuroendocrine cell populations. Pancreatic MiNEN represent 0.5% of all pancreatic adenocarcinomas and 5% of all pancreatic NEN. Methods: A 63-year-old man presented with jaundice and was referred to our hospital for further examination. Abdominal contrast-enhanced computed tomography revealed a mass of 4,3 cm in size in the pancreas head with portal vein narrowing. Pancreatoduodenectomy and regional lymph node dissection were performed. Macroscopically, the ill defined infiltrative tumour was identified at the head of the pancreas. The tumour was 7x3,8x2,5cm in diameter. Results: Histological examination revealed that the tumour consisted of two cell populations.: well differentiated ductal adenocarcinoma (%60), and neuroendocrine tumour cells arranged in a nest, with round nuclei, abundant cytoplasm, and coarse chromatin. Immunohistochemically, the adenocarcinoma cells were positive for MUC1 and MUC5AC, while the neuroendocrine tumour cells were positive for chromograninA, synaptophysin and CD56. Based on the findings, a diagnosis of MiNEN of the pancreas was made. Metastasis of the two components of the tumour was observed in the lymph nodes. Conclusion: We reported an extremely rare case of a MiNEN derived from the pancreas. The clinical features and effective treatment of such tumours have not been well-described due to their rarity. Therefore, more reports of cases of pancreatic MiNEN are necessary for a complete analysis. E-PS-07-035 Incidental IgG4-related autoimmune pancreatitis in a middle-aged patient with suspected pancreatic neoplasia - a case report of an uncommon entity N.J. Lamas 1 , M. Oliveira 1 , L. Ferreira 1 , C. Fleming 1 , R. Amorim 2 , B. Fernandes 2 , J.R. Brandão 2 , F.E. Costa 1 , J.R. Vizcaíno 1 1 Anatomical Pathology Service, Department of Pathology, Hospital and University Center of Porto, Porto, Portugal, 2 Centro Hospitalar do Porto, Portugal Background & Objectives: IgG4-related disease (IgG4-RD) is a fibroinflammatory pathology with either synchronous or metachronous multi-organ involvement. Patients develop focal or diffuse organ enlargement with mass-forming or nodular lesions containing abundant infiltration by IgG4-positive plasmocytes and fibrosis. In pancreas, these lesions frequently mimic neoplasia on imaging studies. Methods: We report the case of a 66-year-old male with a computed tomography scan showing dilated intra-hepatic biliary tree and common bile duct thickening in a 30mm extension in its final portion. A pancreatic head neoplasia was suspected, and the patient underwent cephalic duodenopancreatectomy. Results: A surgical specimen comprising a 7,5x5,5x2,5cm pancreatic head, a 7cm stomach piece and an 11cm duodenal segment was received. Upon section, centered on the pancreatic duct, there was a firm and whitish area, with ill-defined limits, measuring 6x4x4cm. The histological analysis showed a pancreatic parenchyma extensively involved by an intense interlobular fibro-inflammatory process, containing an abundant inflammatory infiltrate rich in plasmocytes, lymphocytes and eosinophils. This process extended to the peri-pancreatic adipose tissue and was close to the mesenteric vein bed. Multiple lesions of obliterative venulitis and phlebitis (highlighted using the Van Gieson elastin staining) were present. The immunohistochemistry study confirmed the presence of numerous CD38+/CD138+/IgG+ plasmocytes and more than 75% were IgG4-positive plasmocytes (beyond 100 IgG4-positive plasmocytes per high-power field). A diagnosis of IgG4-related type 1 autoimmune pancreatitis was made. The ensuing immunological study revealed serum IgG4 levels (1240 mg/dL) nearly 14 times above normal. Conclusion: This case reports an incidental presentation of a pathology less frequent than pancreatic cancer, but which can mimic it on imaging studies. The IgG4-related autoimmune pancreatitis is treated with corticosteroids for at least 3 months, or rituximab in patients with steroid intolerance. A better correlation between serum IgG4 levels, imaging features and biopsy findings could help to avoid pointless surgical approaches and complications. E-PS-07-036 Acinar cell cystadenoma of the pancreas: report of a case and a comprehensive review of the literature C. Vestrup Rift 1 , J. Preuss Hasselby 1 , C. Palnæs Hansen 2 , B. Federspiel 1 1 Department of Pathology Copenhagen University Hospital Rigshospitalet, Denmark, 2 Department of Surgery Copenhagen University Hospital Rigshospitalet, Denmark Background & Objectives: Acinar cell cystadenoma (ACC) is a rare cystic lesion of the pancreas. We hereby present a case of ACC and a review of the literature to characterise the patient population. Methods: A systematic review was performed using PubMed and the keywords “acinar cell cystadenoma” and “acinar cystadenoma”, yielding a total of 24 publications. Results: A total of 75 cases including our case report has previously been described in the literature. The patients are primarily female with presenting symptoms of abdominal pain. The cysts are located in the head of the pancreas, and are often multilocular on cross section with a mean size of 53,2 mm. Microscopically the cysts are lined by a PAS positive acinar epithelium, often with abortive acinar formations. The cells are immunohistochemically positive in stains for trypsin, chymotrypsin and CK7. The Ki67-index is reported low, 1-2%. No malignant transformation has been reported, and the mean follow up time is 37,4 months. Conclusion: ACC is a rare cystic lesion with no malignant potential, primarily affecting women. The indication for surgical intervention should be based on the symptoms of the patients, as no risk of malignancy has been reported. Supported by the Research foundation of Copenhagen University Hospital Rigshospitalet. E-PS-07-037 Acinar cell carcinomas of the pancreas: report of 4 cases E. Ben Hadj Khalifa 1 , A. Bdioui 1 , z. Nfikha 1 , A. Baccouche 1 , T. Zahmoul 2 , B. Sriha 1 , M. Mokni 1 1 Cytology and Pathology Department CHU Farhat Hached, Sousse- Tunisia, 2 Cancer Registry of the Tunisian Center, Tunisia Background & Objectives: Acinar cell carcinoma is a rare malignant tumour of the pancreas, accounting for only 1 to 2% of pancreatic tumours. The diagnosis is based on the pathological examination and immunohistochemistry study. The main differential diagnosis is the neuroendocrine tumours. The treatment is based on surgical resection and chemotherapy. The prognosis is reserved and the average survival does not exceed 18 months.The purpose of this work is to report, from 4 clinical cases and a review of the literature, the clinico-pathological, therapeutic and progressive features of pancreatic acinar cell carcinoma. Methods: Our study was retrospective, descriptive, dealing with 4 cases of acinar cell carcinoma, collected in the laboratory of pathological anatomy and cytology of Sousse, during a period of 10 years. Results: The mean age of the patients was 60 years, with extremes of 50 to 65 years, the sex ratio was 1. The most common clinical sign was abdominal pain. Morphological examinations revealed a pancreatic tumour, which was cephalic in 2 cases and caudal in 2 cases; the size varied from 3 to 15 cm with a solid-cystic aspect, well circumscribed, with presence of foci of necrosis, in the most voluminous tumours. On histological examination, the tumour cells were cubo-cylindrical, with strongly nucleated monomorphic nuclei, organized into small glands and spans. The mitotic activity was variable and the stroma was fibrous. Foci of necrosis were observed. The IHC study showed diffuse expression of trypsin and pancytokeratin (CK). Anti-CK7, CK20, CD10 and C-KIT antibodies were negative. The treatment was surgical corresponding to a spleno-pancreatectomy in one case, and a double diversion with cholecystectomy in another. The other two patients had palliative treatment. The decline ranged from 3 months to 7 years. The evolution was marked by the appearance of hepatic metastases in 2 patients, one with an adrenal metastasis. Conclusion: Pancreatic acinar cell carcinoma is a rare tumour, diagnosed at a late stage, given its clinical latency. Due to the rarity of this neoplasm, its therapeutic approach is still not codified. Surgical treatment with carcinologic resection seems to be the standard treatment. E-PS-07-038 Rare pancreatic tumours: about four cases B. Laabidi 1,2 , R. Hedhli 3 , R. Yaich 1,2 , N. Mansouri 4 , F. Gargouri 4 , A. Saidi 4 , A. Bouziani 4 , I. Msakni 4 1 Tunis El Manar University, Medicine School of Tunis, Tunisia, 2 Military Hospital of Tunis, Department of Pathology, Tunisia, 3 Tunis El Manar University, Medicine School of Tunis Military Hospital of Tunis, Department of Pathology, Tunisia, 4 Pathology Department; Military Hospital for Instruction of Tunis, Tunisia Background & Objectives: The pancreas harbors a wide array of diseases. It involves many uncommon non-neoplastic and neoplastic conditions. As for the rare pancreatic tumours, they can vary from solid to cystic features, ranging from benign to low-grade malignant ones.We report here four cases of three rare histological types of tumours that occur in the pancreas. Methods: The first case is of a 45-year-old female who presented with abdominal pain. The second case concerned a 25-year-old female who was diagnosed with a painful cystic mass of the pancreatic tail. The third case is of a 41-year-old man who presented with a solid epigastric mass. The fourth case reported a 69-year-old male who was diagnosed with a pancreatic tail tumour. Results: In the first and second case, histopathological examination and immunohistochemistry on biopsy led to the diagnosis of solid pseudopapillary pancreatic tumour. Both patients underwent respectively pancreatoduodonectomy and distal pancreatectomy. In the third case, the diagnosis of Solitary fibrous tumour was concluded on histological and immunohistochemical findings on biopsy. The patient was treated surgically. The operative follow-up was marked by a diffuse hemorrhagic syndrome leading to the patient’s death on the 3rd post-operative day. In the last case, microscopic features on lumpectomy confirmed the diagnosis of pancreatic lymphangioma. Conclusion: The pancreas may be involved with a large variety of unfrequent solid or cystic neoplasms. Therefore, operative exploration is the treatment of choice of these rare lesions to provide the correct diagnosis based on histological examination and initiate adequate surgical therapy. E-PS-07-039 Latent pancreatic metastasis, 13 years after renal cell carcinoma - a case report M. Danciu 1 , C.E. Andriescu 2 1 Grigore T. Popa UMF Iasi, Romania, 2 Sf. Spiridon Emergency County Hospital Iasi, Romania Background & Objectives: Pancreatic metastasis represent less than 4% of all pancreatic tumours, about 1-4% originating from renal cell carcinomas (RCC). We present the case of a solitary pancreatic metastasis occurring 13 years after nephrectomy, in a 69-year-old female patient. Methods: The surgical resection specimen was submitted for intraoperative consultation (frozen sections). HE staining and immunohistochemical tests were performed after routine processing of the whole sample. Results: Gross examination revealed a well circumscribed yellow 2.2 cm nodule, in the pancreatic isthmus. On frozen section examination, the tumoural nodule consisted of isles and trabeculae of large round cells with central hyperchromatic nuclei surrounded by finely vacuolar cytoplasm. Lacking the relevant clinical information regarding patient history, a diagnosis of malignancy was provided. The histological examination of the paraffin embedded tissue yielded new morphological details of the tumour population: polygonal cells with clear cytoplasm and moderate pleomorphism, inconspicuous mitotic activity, sparse vascular stroma, peripheral fibrosis. The suspicion of pancreatic metastasis of RCC was advanced based on tumour morphology and patient’s history of nephrectomy (provided upon request). Immunohistochemical tests (positive for RCC, CK7, CD10; negative for CK20) confirmed the diagnosis. Conclusion: In absence of the oncological history of the patient, a solitary pancreatic nodule may raise difficulties on frozen section examination in differentiating a primary pancreatic tumour from a metastasis. As about 70% of pancreatic metastasis originates from RCC, one should always consider this scenario, even if the RCC was resected more than one decade ago, as in our patient. E-PS-07-040 A rare case of pancreatic carcinosarcoma with unique histological pattern I.A. Spiridon 1 , S. Lunca 1,2 , D. Ferariu 3 1 "Grigore T. Popa" University of Medicine and Pharmacy Iasi, Romania, 2 Second Clinic of Surgery, Regional Institute of Oncology, Iasi, Romania, 3 Department of Pathology, Regional Institute of Oncology, Iasi, Romania Background & Objectives: Carcinosarcoma is a rare biphasic tumour with epithelial and mesenchymal features, most commonly arising in the uterus. The pancreatic location of this neoplasm is an extremely rare finding, with few cases recorded in literature. We report the occurrence of a pancreatic carcinosarcoma in a 63-year-old male patient. Methods: Multiple samples from the complex surgical resection specimen were routinely processed. HE staining and immunohistochemical tests were performed. Results: On gross evaluation, the resection specimen revealed a tumoural mass apparently originating in the pancreas and engulfing several other organs (duodenum, colon, left kidney, spleen). The histological examination identified two distinct areas, a tumoural population of epithelial origin, forming microlobular to trabecular aggregates, with abundant eosinophilic cytoplasm and marked nuclear pleomorphism, in collision with a highly cellular proliferation of spindled cells, with sarcomatous morphology and notable pleomorphism, often with bizarre, multinucleated cells. Mitotic activity was increased in both of the tumoural populations, with an associated Ki-67 index of over 90%. Immunohistochemistry confirmed the epithelial component as neuroendocrine carcinoma (positive CKAE1/AE3, Chromogranin, Synaptophysin), while the spindled area was classified as undifferentiated pleomorphic sarcoma, with negativity for CKAE1/AE3, EMA, CK7, CD117, CD34, SMA, Desmin and positivity for Vimentin. Conclusion: This is, to our knowledge, the first reported case of a pancreatic carcinosarcoma associating a malignant neuroendocrine component with an undifferentiated pleomorphic sarcoma component. While with recent studies argue for the monoclonal origin of this tumour, its prognosis remains dismal, with otherwise limited consensus regarding surgical management and postoperative treatment. E-PS-07-041 Glycogenic hepatopathy - an underrecognised clinicopathological entity A. Baltan 1 , I. Simionov 1 , A. Constantinescu 1 , G. Becheanu 1 1 Fundeni Clinical Institute, Romania Background & Objectives: We present the case of a 21-year-old male with type 1 diabetes mellitus, who complained of weight loss and fatigue, having elevated transaminase, gamma glutamyl transferase and glucose blood levels. Abdominal ultrasound showed hepatomegaly and diffuse liver hyperecogenicity, which was considered to represent mild steatosis. Autoimmune hepatitis was suspected and serologic tests showed slightly increased anti-nuclear antibodies levels and absence of a viral liver infection. Methods: The sampled liver tissue was immediately immersed and fixed in 10% neutral buffered formalin solution, 3 μm thick sections were obtained and H&E, Perls and van Gieson stains were performed. Results: The liver biopsy had a total length of 10 mm. The lobular architecture was preserved and the portal spaces were unremarkable. The hepatocytes were diffusely enlarged, with abundant clear cytoplasm and visible cytoplasmic margins. Rare steatotic macrovesicles and relatively frequent megamitochondria were present. The hepatocyte nuclei varied slightly in size and some of them were glycogenated. No inflammation was noted, except for a few intralobular neutrophils, and fibrosis was not identified. The histopathological diagnosis was glycogenic hepatopathy. The pacient received a adequate insulin regimen and is currently on follow-up, with clinical improvement. Conclusion: Glycogenic hepatopathy is a rarely reported entity, with an unspecific clinical pattern. It should be suspected in diabetic patients, particularily with type 1 diabetes mellitus, and liver abnormalities. Liver biopsy exammination is needed for a definitive diagnosis. E-PS-07-042 Alpha-smooth muscle actin and vimentin expression in primary liver carcinomas may relate with epithelial-mesenchymal transition carcinogenesis L. Carvalho 1 , A.F. Ladeirinha 1,2 , A. Alarcão 1,2,3 , L. Neves 1 , R. Santos 4 , J. Espírito Santo 5 1 Institute of Anatomical and Molecular Pathology, Faculty of Medicine of the University of Coimbra, Coimbra, Portugal, 2 CIMAGO - Research Center for Environment, Genetics and Oncobiology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal, 3 Centre of Pulmonology, Faculty of Medicine of the University of Coimbra, Portugal, 4 Internal Medicine Department A, Coimbra Hospital and Universitary Centre, Portugal, 5 Adult and Paediatric Liver Transplantation Unit, Coimbra Hospital and Universitary Centre, Portugal Background & Objectives: Hepatocellular carcinoma (HCC) represents 85-90% and intrahepatic cholangiocarcinoma (iCC) 10-25% of all primary liver carcinomas (PLC), where epithelial-mesenchymal transition (EMT) may play a key role in hepatocarcinogenesis. Thought to be associated with the acquisition of aggressive traits by tumour cells, alpha-smooth muscle actin (αSMA) and vimentin may be specific markers of epithelial - mesenchymal origin. αSMA and vimentin expression was evaluated in HCC and iCC. Methods: One-hundred and thirteen epithelial malignant liver lesions were studied, from 52 consecutive patients undergoing resection or liver transplantation. Pathological review was performed and tumours were classified according to World Health Organization 2010. αSMA actin and vimentin expression was considered positive when single tumour cells or tumour cell clusters showed immunoreactivity, whereas negative expression was defined as no detectable expression. Results: From the 18 early HCC studied, 6 (33,3%) had αSMA expression and 10 (55,6%) were vimentin-positive, 12 (66,7%) showed perinodular αSMA positive hepatocytes and 12 (66,7%) perinodular vimentin positive hepatocytes; of the 56 advanced HCC, 19 (33,9%) expressed αSMA and 30 (53,6%) had vimentin positive cells, 26 (46,4%) presented perinodular αSMA in hepatocytes and 26 (46,4%) perinodular vimentin positive hepatocytes; none from the 6 iCC expressed αSMA and 4 (66,7%) had vimentin expression, perinodular hepatocytes expressed αSMA in 4 (66,7%) iCC and perinodular hepatocytes expressed vimentin in 5 (83,3%). Conclusion: αSMA and vimentin expression either in tumour cells of HCC and iCC may correlate with EMT. Dedifferentiation of liver epithelial benign/malignant cells reflects the importance of tumour microenvironment in PLC development, which may retain clinical specificities. E-PS-07-043 An unusual case of metastatic liver melanoma in a patient with chronic lymphocytic leukemia A. Sykaras 1 , A. Paraskevas 1 , D. Sampaziotis 1 , K. Pavlou 1 , K. Roidou 1 , C. Kouvidou 1 1 Department of Pathology, Evangelismos General Hospital, Athens, Greece Background & Objectives: The major hematologic conditions in patients with multiple malignancy are multiple myeloma, myelodysplastic syndromes, non-Hodgkin’s lymphoma (NHL) and chronic lymphocytic (CLL) or myelogenous leukemia. Specifically, patients with a history of CLL or NHL have a higher incidence of melanoma. If they are synchronous the patient’s prognosis may be adversely affected. Methods: We present a 69 years old man with a history of CLL treated with chemotherapy three years ago. The patient presented to haematology department with fever, weight loss and anorexia. The CT scan revealed multiple foci in the liver and a needle biopsy was performed. Results: The needle biopsy showed two distinct neoplastic populations. The first consisted of small to medium size lymphocytes with immunophenotype CD20+, Pax-5+, CD5+, CD23+ and LEF-1+ suggesting liver infiltration from CLL cells. A second population of epithelioid cells with visible nucleoli and immunophenotype Melan-A+, HMB45+, S100+, MITF-1+, BRAF V600E- established the diagnosis of malignant melanoma. Our patient has not a known melanoma in skin or gastrointestinal tract. Conclusion: The coexistence of CLL with melanoma has been reported in lymph nodes but not in the liver, to our knowledge. It has been suggested that in CLL the dysfunctional lymphocytes are unable to elicit an antitumour response, thereby contributing to the increased incidence of carcinomas and melanomas in these patients. Moreover, the immunosuppressive effect of chemotherapeutic agents and irradiation used to treat NHL increase the risk of cancer in these patients. E-PS-07-044 A rare case of granular cell tumour in the biliary tract A. Sykaras 1 , S. Pantelakos 1 , D. Sampaziotis 1 , K. Botsakis 2 , C. Stamou 1 , N. Stavrinou 1 , C. Kouvidou 1 1 Department of Pathology, Evangelismos General Hospital, Athens, Greece, 2 Department of Surgery, Evangelismos General Hospital, Athens, Greece Background & Objectives: Granular cell tumours (GCT) are rare usually benign neoplasms although some of them may be focally aggressive and <2% are malignant. GCTs may be found in the tongue, skin, gastrointestinal tract, lung, urinary bladder, breast and thyroid. Biliary GCTs represent <1% of all the GCTs and are rarely diagnosed preoperatively, <90 cases have been reported in the literature and no cases of malignant GCT has been published. Methods: A 57 years old woman was presented to surgical department with jaundice, mild pruritus and abdominal pain. Ultrasound imaging, CT scan and MRI revealed excessive dilation of the endohepatic and extrahepatic biliary tree and an ovoid solid mass of 13mm located in the common bile duct. The endoscopic needle biopsy were not performed due to the location of the tumour and a whipple procedure was performed due to the suspicion of cholangiocarcinoma. Results: The gross examination revealed a yellow solid tumour 1mm causing thickness of the wall and partly obstruction of the duct. The histopathological features and the immunohistochemistry (S100+, CD68+, inhibin a +, actin-, desmin-, CD117-) were consistent with a benign granular cell tumour. No necrosis, no atypia, no increased mitosis were seen. Radiation or chemotherapy were not recommended. 16 months postsurgically the patient showed no signs of disease. Conclusion: GCTs of biliary tree are commonly found in the common bile duct (58-49%) and in common hepatic duct (23%). Myoblasts, histiocytes, fibroblasts, undifferentiated mesenchymal cells and schwann cells have been implicated but the histogenesis still remains unknown. E-PS-07-045 Correlation between radiologic diagnosis and pathological results in resectable pancreatic neoplasms G.M. Parini 1 , M.T. Rodrigo Calvo 1 , M. González Farrè 1 , C.V. Martinez Stocker 2 , F.F. Díaz Rojas 2 , M. Pumar Perez 2 , G. Aguilar Sanchez 2 , X. Duran 3 , A. Radosevic 2 , B. Lloveras Rubio 1,4,3 , M. Iglesias Coma 1,4,3 1 Pathology Department. Hospital del Mar, Barcelona, Spain, 2 Radiodiagnostic Department. Hospital del Mar, Barcelona, Spain, 3 Institut Hospital del Mar d'Investigacions Mèdiques, Spain, 4 Universidad Autónoma de Barcelona, Spain Background & Objectives: Diagnostic imaging is important to evaluate pancreatic neoplasms. Accurate detection and staging are essential for ensuring appropriate treatment. The radiologic diagnosis includes the macroscopic appearance, neoplastic type, staging and atrophy, among others. Pathological reports include also these variables. We want to establish the correlation between the pre-surgical radiologic diagnosis and the final pathological report. Methods: We reviewed the radiological and pathological report of 120 surgical pancreatic lesions (2014-2018, Hospital del Mar). The variables collected were: location, macroscopy, diagnosis, staging, lymph nodes and atrophy. We use the Cohen's kappa coefficient statistical test to find the correlation. Results: The correlation between radiological and pathological diagnose is 71,43% (k of 0,58). The differences in diagnosis are mostly related to neoadjuvant treatment, malignant cystic lesions without cystic component in surgical specimens and NET-like in radiology consistent with clear cell renal carcinoma metastasis. There is 97,17% in agreement in location and 60,5% in macroscopy. The correlation drops in relation with affected lymph nodes (58,47%) and with atrophy (50%). Conclusion: We found an optimal correlation between radiological and pathological diagnoses, which is important in order to establish a possible surgical treatment and behaviour, and also with location. In addition, we are able to explain the cause of the discrepancy in the majority of un-correlated cases. E-PS-07-049 Solid-pseudopapillary neoplasm of the pancreas: an institution's experience and literature review G. Gerardo 1 , R. Veiga 1 , A. Catarino 1 1 Hospital da Luz Lisboa, Portugal Background & Objectives: The rare solid-pseudopapillary neoplasm of the pancreas (SPNP) occurs predominantly in young females; after complete surgical resection, about 85-95% of patients are cured. Long disease-free periods have been recorded even in patients with local spread or metastasis. We present a patient with an unusual clinical picture of SPNP, and a review of the literature. Methods: A 27-year-old female with complaints of abdominal pain and nausea had a CT-scan that depicted a mass of possible pancreatic origin in her left flank. Multiple nodules were reported in the abdominal and pelvic cavities. A core biopsy was performed and the lesion was classified as SPNP. Results: The tumour was excised and the diagnosis of SPNP was confirmed, based on the morphological pattern and immunocytochemistry studies. A CTNNB1 mutation was found. Regarding the seven cases of SPNP we retrieved from our files, between 2011 and 2018, the male: female ratio was 1:6 and the age ranged between 18-68. This case was the only one showing disseminated disease at the time of diagnosis. A follow-up was available in 5 cases (from 1-8 years) and all the patients are well and asymptomatic. Conclusion: SPNP can display abdominal widespread disease in a minute number of cases, with no apparent prognostic implications. This clinical picture does not seem to correlate with a particular histological pattern. Our patient has a follow up time (12 months) free of symptoms and with minimal residual disease at second look MRI. Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-08 | Endocrine Pathology Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-08 | Endocrine Pathology E-PS-08-001 Alveolar echinococcosis of the adrenal, accidental discovery Z. Merad 1 1 CHU Sidi Bel Abbes, Algeria Background & Objectives: We repport a case of alveolar echinococcosis confirmed histologically discovered in bilan of extension at a woman presented a cancer of the endometrium and discuss the differential diagnosis. Methods: 75-year-old woman, followed in gynaecology for a cancer of the endometrium to whom the realized abdominal ultrasound found a mass in the right adrenal heterogeneous of 6 cms on 4 cms of size. The biological examinations were normal (17 ketostéroïd, 17 hydroxycortisone, metanephrine and acid vanillyl-mandelic). The abdominal CT objectified an adrenal mass heterogeneous right of 6 cms on 4 cms. This mass adrenal is not functional who raised a problem of natural diagnosis. Results: A coelioscopy explorer was practised with an extemporaneous examination which showed a fibrous fabric reshaped by the necrosis and the beaches microphone - abscess which did not end in a diagnosis of certainty. A right adrenalectomy was practised. The histologically adrenal gland was completely erased by alveolar architecture, of many cavities of variable sizes which contained fragments of cuticle with presence in their lights of proto scolex. The evolution after operating were simple and patient went out one week later. Conclusion: Alveolar hydatid disease of the adrenal is an exceptional pathology it will raise with any cystic tumour of the adrenal, especially in endemic countries. However, the definitive diagnosis remains the prerogative of the pathological examination, especially as prevention is difficult given the parasitosis cycle takes place in nature. E-PS-08-003 Case report: co-existance of papillary thyroid carcinoma and follicular carcinoma as a rare collision tumour M. Shariati 1 1 Surgical Pathology Laboratory, Iran Background & Objectives: The simultaneous occurrence of different types of thyroid carcinoma in a single patient is a rare event.Synchronization of PCT and follicular thyroid carcinoma (FCT) is very rare.So far a few cases (less than 5 cases) of the simultaneous occurrence of the papillary thyroid carcinoma and follicular thyroid carcinoma have been reported.This article introduces a rare thyroid malignant case in the world that shows bilateral collision tumour of Papillary thyroid carcinoma and Follicular thyroid carcinoma in a 66 year-old iranian female. Methods: In macroscopic examination, total thyroid weight was 30 g and measured(right: 4.5 * 3.0 * 2.0 centimetres and 1.2 cm 3.0 * 2.2 * 1.5 centimetres).Also, the gross evaluation of specimen showed encapsulated thyroid without macroscopic capsular invasion.Serial cutaways revealed several nodules with different size and calcification which were filled the whole right thyroid lobe.The largest one was 3.5 cm in dimension.One the other side,there were two nodule without calcification in the left lobe( the great dimension was 3.0 cm). Results: Microscopic histopathological examination of right nodule confirmed papillary thyroid carcinoma with complex branching papillae, fibrovascular cores and characteristic nuclear features: nuclei show overlapping, optically clear chromatin, nuclear longitudinal grooves and eosinophilic intra-nuclear inclusions.And left nodule slides revealed encapsulated follicular carcinoma with capsular invasion. Solid pattern of small and normal size follicles without nuclear features of papillary thyroid carcinoma.ΩCapsular invasion were noted in two sites. One site: full thickness penetration through the capsule and the other: mushroom-like invasion through the capsule. Conclusion: Our presentation expresses the presence of two distinct types of thyroid carcinoma (papillary and follicular carcinoma) in two different lobes, which in turn is very rare in the world. We discussed some hypothesis for explaining the simultaneous occurrence of thyroid carcinomas in this case report article. E-PS-08-005 Concomitant pheochromocytoma and adrenal adenoma in the same adrenal gland T.M. Costa 1 , C. Albuquerque 1 , R. Sampaio 1 1 Centro Hospitalar Lisboa Ocidental, Portugal Background & Objectives: Both adrenal adenoma and pheochromocytoma in the same adrenal gland concomitantly is a rare pathology, to our knowledge with only 6 reported cases until now. Methods: A 61-year-old female, presented with primary hyperaldosteronism and a left adrenal gland mass on the CT scan which was consistent with adrenocortical adenoma. Her past medical history was resistant arterial hypertension, type 2 Diabetes Mellitus and hypercholesterolemia. The biochemical tests showed hyperaldosteronism, strongly suggesting the diagnosis of adrenal gland adenoma, and so she underwent surgical removal. The pathological gross examination of the suprarenalectomy specimen revealed two separate tumours: one yellow cortical nodule 1x0.9x0.7cm and a greyish medullary one with 0.6x0.6x0.5cm. Results: On microscopic examination we identified an adrenocortical adenoma and a pheochomocytoma. There has been reported cases associating essential hypertension and pheochromocytomas to cause adrenal hyperplasia and consequent adrenal adenoma formation. In fact the incidence of adrenal adenomas in patients with essential hypertension is increased. So there is a chance that our adrenal adenoma could be resultant of an undetected pheochromocytoma. Conclusion: We think that this case is noteworthy in highlighting the importance of biochemical tests studying an adrenal mass to rule out pheochromocytoma prior to surgery, especially due to possible dangerous intra-operative hemodynamic consequences, as well to understand the hypertension ethiology. E-PS-08-006 Familial paraganglioma and morphologic criteria importance T.M. Costa 1 , C. Albuquerque 1 , R. Sampaio 1 1 Centro Hospitalar Lisboa Ocidental, Portugal Background & Objectives: Paraganglioma is a rare neuroendocrine tumour that arise from neural crest cells. Despite of great importance, there is still no consensual morphologic prognostic criteria for these tumours. Methods: A 46-year-old woman presented to our emergency department due to tension headache followed by nausea, sweating and syncope associated with extreme arterial hypertension. After exclusion of neurological and cardiogenic causes it was found an intra-abdominal mass; Adherent to left renal vein, limited superiorly by the spleen, laterally by the left kidney and adrenal gland, and posteriorly adherent to the thoracic vertebra. The laboratory workup showed elevation of methanephrines, and with high suspicion of a paraganglioma she underwent surgical removal. Results: On gross examination was a nodule with 39g and 6,5x4,5x3cm, in section yellow with central cystic area of hematic content. Histologically was a paraganglioma, with large and irregular cell nests, moderate cellularity, pseudorosettes, vascular invasion, Ki67 3-5% and capsular infiltration. According to Grading System of the Adrenal Phaeochromocytoma and Paraganglioma (GAPP) the tumour was classified as moderately differentiated. Conclusion: The immediate follow-up was benign; however, 3 months later, the patient is having symptomatology recurrence. Genetic testing disclosed a familial paraganglioma, with a germline mutation in succinate dehydrogenase-subunit B gene, which has worse prognosis. The pathological report in this case was crucial to identify an uncommon paraganglioma and alert the clinicians for patient vigilance, genetic testing and evaluation of relatives. E-PS-08-007 Morphological features of the parathyroid glands in rats under heavy metal salts influence O. Tymakova 1 , N. Hryntsova 1 , O. Romaniuk 1 , Y. Kuzenko 2 , A. Korobchanska 3 , I. Kravtsova 1 , A. Romaniuk 1 1 Sumy State University, Ukraine, 2 Sumy State University, Department of Pathology, Ukraine, 3 Kharkiv National Medical University, Kharkiv, Ukraine Background & Objectives: The aim of this study was to explore the morphological features of the parathyroid glands in the experimental animals under the heavy metal salts influence. Methods: The experiment was conducted on 18 mature male albino rats, which were divided into 3 groups. The first group (C) was the intact animals. During 30 days the rats of the second group (HMS 30), as well as the animals of the third group (HMS 90) during 90 days got the water solution of heavy metal salts mixture (Zn,Cu,Fe,Mn,Pb,Cr). The functional activity of the parenchymatous glands structures was immunohistochemically assessed, the expression of the chromogranin in cells was determined. Results: On the 90th day the capsule thickness was nearly twice thicker, the connective-tissue layers in the parenchyma were increased in 3.8 times. The hypertrophy, as well as cytoplasm vacuolization were observed in the parathyrocytes. The parathyrocytes area in experimental animals was twice increased, on the 90th day – in 1.9 times. The cell nucleus area increased in 2.3 times on the 90th day. The immunohistochemical study revealed the suppression of the chromogranine expression in the parathyrocytes. Conclusion: The toxic action of heavy metal salts was the most significantly expressed on the 90th day by the proliferation of the connective-tissue capsule. The increased area of parathyrocytes and cell nucleus area was observed. The most significant increase in the cell nucleus was observed on 90th day. The chromogranine expression decreased under the heavy metal salts influence. E-PS-08-008 Clinical presentation of medullary thyroid carcinoma as "triple negative" breast cancer: case report and literature review M. Mchedlishvili 1 , N. Kekelidze 2 , K. Khachapuridze 2 , E. Imerlishvili 2 1 A. Natishvili Institute of Morphology, TSU, Georgia, 2 TSU, Georgia Background & Objectives: Medullary Thyroid Carcinoma is a malignant tumour of C-cells, which can be manifested in different organs as a metastatic disease. The most common metastatic sites are - bones (45%), lungs (33%), brain (1-5%) skin and rarely in breast. According to the literature only 25 cases of medullary thyroid cancer metastasis in breast are described. None of them was primarily manifested in breast involving axillary lymph nodes as well. Methods: The article describes clinical cases of two patients with medullary thyroid carcinoma.The first case describes 71 years old man with medullary thyroid carcinoma in breast, lesion localization - in the upper-lateral quadrant of the breast, tumour size was 3.2 x 2.0 x 1.8 cm (the first patient). The second patient was 13 year-old boy with thyroid medullar-microcarcinoma. The both patients were examined by immunohistocemistry. Examination was done with surgical samples of tissue. Results: The first patient - negative expression of ER,PR,HER-2. Expression of proliferation marker Ki67 was very low. S100 (+) – expressed in tumour cells; Calretinin - strongly positive; Post surgical thyroid ultrasound examination revealed 1.7 cm tumour in the left lobe. Calcitonin level in blood was 1037. 4pg/ml. The multiple metastasis caused patient death within three years. The second patient - following our recommendation patient’s grand-child examined and 0.4 cm thyroid medullary carcinoma of the left lobe was diagnosed. Conclusion: There are extremely rare cases of Medullary Thyroid Carcinoma with clinical manifestation in breast as a “classical” breast cancer. “Triple negative”malignant lesions of breast need carefully examination to exclude tumour metastasis in breast. In order to verify malignancy at an earlier stage, screening of patient’s family members is very important. E-PS-08-009 Value of Cytokeratin 7 expression to determine the origin of metastases of neuroendocrine tumours L. Gurevich 1 , V. Ashevskaya 1 , E. Bondarenko 1 , I. Voronkova 1 , M. Byakhova 1 1 The State Budgetary Healthcare Institution of Moscow Area Moscows Regional Research Clinical Institute n.a. M.F. Vladimirskiy, Moscow, Russia Background & Objectives: Recently, the problem of determining the localization of a primary neuroendocrine tumour (NET) on the material of diagnostic biopsies of metastases of NET of unknown origin has become increasingly urgent. Methods: The expression of cytokeratin 7 (CK7) was analysed 271 NETs of various localization: 14 NET pancreas, 36 stomach (22 G1, G2; 8 G3: 4 small cells neuroendocrine carcinomas(SCNEC), 4 large cells(LCNEC)), 6 NET duodenum, 214 - lungs (100 typical (TC) and atypical carcinoids(ATC); 85 SCNEC, 19 LCNEC), 6 - mediastinum, 14 - medullary thyroid cancers(MTC), 8 - breast, 4 – kidneys, 2 - tracheas, 2 - nasopharynx. Results: The expression of CK7 was detected in 100% of MTC, breast, trachea, and was completely absent in all NETs of the pancreas, duodenum, Merkel carcinomas, nasopharyngeal carcinoids and kidney. Expression of CK7 was detected in 22.7 (5/22) gastric carcinoids G1, G2, and in 75% (6/8) and NEC G3, in 17% (9/53) TC and 54.4% (27/47) ATC of lung, in 51.6% (49/95) of SCNEC and 68.4% (13/19) of LCNEC of lung, 16.7% (1/6) of mediastinal carcinoids. Conclusion: Expression of CK7 in diagnostic biopsies of NET metastases of unknown origin allows to exclude the localization of primary tumours in the pancreas, intestines, skin, nasopharynx, kidney; suggests their origin from the thyroid gland, breast, trachea and for CK7-positive SCNEC and LCNEC the probability of their localization in the lung and stomach is very high. E-PS-08-011 Thyroid angiosarcoma in a non-alpine country. A case report and review of the literature P. Ravazoula 1 , D. Koumoundourou 1 , E. Mpota 1 1 University Hospital of Patras, Greece Background & Objectives: Thyroid angiosarcoma is a malignant neoplasm which is reported in Alpine region countries of central Europe. It is manifested as a ‘cold nodule” most often in eldery female patients. We present a case of thyroid angiosarcoma in a non-alpine country. Methods: A 69 years old woman presented with a right lobe thyroid nodule measuring 2,2cm. in greatest diameter. Ten years ago she had underwent a total mastectomy and had recieved radiotherapy. Fine needle aspiration cytology revealed “epithelioed malignant cells”. Histological examination showed a malignant neoplasm with areas of necrosis and anastomosing channels lined by medium size cells with abundant eosinophilic cytoplasm, large nucleus with prominent nucleoli and numerous typical and atypical mitoses. There was invasion of sternoyoid muscle. Results: Immunocistochemically tumos cells were positive for CD31, CD34 and Vimentin, focally positive for low molecular weight keratins and S-100 protein and negative for thyroglobulin, calcitonin, galectin, TTF-1, Melan A, HMB45, ER, PR, CEA. The diagnosis was that of an angiosarcoma. Conclusion: We described a case of thyroid angiosarcoma in a patient living in a non-alpine region with a history of radiation therapy. Thyroid angiosarcomas are rare malignant tumours mainly with poor prognosis and most patients die in less than six months. Differential diagnosis includes anaplastic thyroid carcinoma with angiomatoid feature. E-PS-08-012 Primary paraganglioma of thyroid gland: a rare case report with clinicopathologic and immunohistochemical analysis R.A. Barna 1 , M. Cornianu 2 , A. Faur 3 , G. Oprisan 1 , A. Dobrescu 4 , F. Lazar 4,5 1 Department of Pathology, University of Medicine and Pharmacy „Victor Babes", Timisoara, Romania, 2 V. Babes University of Medicine and Pharmacy, Romania, 3 Anatomy and Embryology Department, University of Medicine and Pharmacy „Victor Babes", Timisoar, Romania, 4 Surgery Department II, University of Medicine and Pharmacy „Victor Babes", Timisoara, Romania, 5 Surgery Department II, Emergency County Hospital Timișoara, Romania Background & Objectives: Primary thyroid paraganglioma (PTPG) is a rare and unusual neuroendocrine tumour, most of the times it can be mistaken for other thyroid neoplasms. This study reports a case of PTPG accompanied with euthyroidism, which mimics medullary thyroid carcinoma, from a 44-year-old woman who presented with dyspnea and dysphonia caused by an anterior cervical lesion. Methods: Physical examination revealed a painless, well-circumscribed thyroid nodule of 3 cm within the left lobe, with normal mobility and without palpable cervical lymphadenopathy. Ultrasonography (US) of the thyroid gland showed a nodule in the left lobe measuring 30 mm, hypoechoic, with increased intranodular vascular flow. The laboratory examination results were in normal range. US and computed tomography had no diagnostic value. Later, the patient underwent surgical resection of the left thyroid lobe. Results: PTPG diagnosis was determined by histopathological features and confirmed by immunohistochemical staining. The specimen showed positivity for chromogranin A (CgA), synaptophysin (Syn), neuron-specific enolase (NSE) and CD56, whereas it was negative for TTF-1, calcitonin and carcinoembryonic antigen (CEAm); S-100 protein was positive in sustentacular cells located at the periphery of the tumour cell nests. After performing surgical resection as a curative approach, at 36 months of follow up there is no local recurrence or metastasis. Conclusion: Becoming aware of the existence of PTPG and recognizing its histological characteristics is essential for the diagnosis and treatment of the lesion. Even though it is hard to diagnose, PTPG seems to have a favourable prognosis and preferred treatment option is total thyroidectomy with long-term follow-up. E-PS-08-013 Neuroendocrine tumours: an observational study V. Tudorache 1 1 Universitatea de Medicina si Farmacie Targu Mures, Romania Background & Objectives: Neuroendocrine tumours (NETs) predominantly affects the gastrointestinal tract but other organs can also be involved. The aim of the paper was to perform a retrospective evaluation of NETs diagnosed in our department in the last years. Methods: Consecutive cases of NETs diagnosed during 2009-2017 in Department of Pathology of University of Medicine, Pharmacy, Sciences and Pathology, were retrospectively evaluated. Results: There were 175 cases diagnosed in 9 years, with a median number of 19.44±5.27 cases per year (range 11-28) and a M:F ratio of 1.18:1. The median age of patients was 59.09±15.75 years (range 8-92 years). The predominant locations were appendix (34%), stomach (17%) and pancreas (16%), followed by tumours of colorectal segments (9%), small intestine (7%), lung (7%) and adrenal glands (3%). The other cases (7%) were diagnosed in genital organs, head and neck area, and gallbladder. Most of the tumours (n=132) were carcinomas (36 out of 132 cases showed lymph node metastases), the other 43 tumours being diagnosed as G1- (n=33), G2- (n=5) or G3-NETs (n=5). Conclusion: Most of the NETs are localized in the gastro-entero-pancreatic area and show a malignant behavior. This work was supported by a grant of the Romanian National Authority for Scientific Research, CNCS – UEFISCDI, project number 20 PCCF/2018, code: PN-III-P4-ID-PCCF-2016-0006. E-PS-08-015 Multiple solid cell nests accompanying amyloid goiter: a rare case report Î Kaya 1 , S. Ekmekci 2 , Į Sert 3 , Î Küçük 1 1 Izmir Tepecik Education and Research Hospital, Department of Pathology, Turkey, 2 Izmir Tepecik Training and Research Hospital, Department of Pathology, Turkey, 3 Izmir Tepecik Education and Research Hospital Department of General Surgery, Turkey Background & Objectives: Amyloid goiter is a disease that results in diffuse growth of the gland due to the accumulation of amyloid protein in the thyroid gland. In systemic amyloidosis, all the organs as well as thyroid glands can be infiltrated with amyloid.This report presents a new case of amyloid goiter with diffuse fat deposition which may be confused with other pathological conditions of the thyroid gland. Methods: A 32-year-old male patient, had undergone renal transplantation 5 years ago due to chronic renal failure, was admitted to our endocrinology department with a rapidly increasing mass localized in front of his neck and hypothyroidism findings. In the macroscopic examination of the patient who underwent total thyroidectomy, thyroid gland was lobule, solid appearance. Microscopic examination of the thyroid revealed diffuse infiltration of the parenchyma by mature fat tissue and atrophic thyroid follicles. An eosinophilic amorphous material consistent with amyloid substance infiltrated these fat tissue. This material stained intensely with Congo red and was apple green in color under polarized light. Most of the areas of the thyroid gland consisted of solid cell nests between these fat tissue. Results: Amyloidosis is results from the deposition of insoluble, fibrous amyloid proteins, nearly always in the extracellular spaces of organs and tissues. Amyloid deposition in the thyroid parenchyma is rare and usually accompanies medullary carcinomas. Conclusion: The origin of adipose tissue accompanying amyloid goiter is unknown.Diffuse accumulation of metaplastic fat tissue should be differentiated from diffuse thyrolipomatosis of thyroid gland. Amyloid stains can be helped us for the differential diagnosis. E-PS-08-016 Neuroendocrine cells relevant to endocrine mammary and cutaneous carcinomas: nature and significance T. Kawasaki 1,2 , T. Kubota 2 , R. Katoh 3,4 , T. Kondo 3 , S. Ichihara 2 , K. Horibe 2 , H. Nagai 2 , M. Takahashi 5 1 Saitama Medical University International Medical Center, Japan, 2 National Hospital Organization Nagoya Medical Center, Japan, 3 University of Yamanashi, Japan, 4 Ito Hospital, Japan, 5 Nagoya University, Japan Background & Objectives: The developmental mechanisms of neuroendocrine carcinomas (NECs) of the breast and the skin have not been sufficiently analysed and are not well understood. The aim of this study was to investigate neuroendocrine (NE) cells in the background tissues surrounding mammary and cutaneous NECs. Methods: Four Japanese cases (four breasts and one eyelid) having solid papillary NECs accompanied by many NE cells were identified. These patients were, respectively, 28-, 31- and 38-year-old women (breasts) and 51-year-old man (eyelid) with no familial history of NE tumour. The totally resected breasts and excised skin of the eyelid were serially studied by immunohistochemistry for specific NE markers and the morphologies and/or localization of NE cells were investigated. Results: Immunohistochemical examination showed extensively-distributed NE cells in the background terminal duct-lobular units or sweat ducts of NECs. These NE cells reactive for chromogranin A and/or synaptophysin were classifiable into three emerging patterns: isolated/scattered, clustered and circumferential. NE cells were morphologically polygonal, oval or columnar with sometimes eosinophilic and/or fine-granular cytoplasm and round-to-ovoid nuclei lacking atypia. Some cells were located between epithelial and myoepithelial cells. Apical snouts were occasionally observed in NE cells forming luminal structures. Conclusion: Benign-looking NE cells in the parenchyma of a skin as well as a breast with NEC could be regarded as hyperplastic from their emerging patterns and distribution; this “NE cell hyperplasia” may be associated with the histogenesis of NEC as a precancerous condition. These observations might raise questions about the treatment for NEC. ( J Clin Pathol , 2012 & Pathology , 2018). Grants-in-Aid for Scientific Research (16K08654 & 16H00668) from the Japanese Ministry of Education, Culture, Sports, Science and Technology and National Hospital Organization (NHO) Grant (H29-NHO-01). E-PS-08-017 Bone metastases of unknown primary in a patient with bilateral ovarian tumour and thyrotoxicosis - an unusual case of highly differentiated follicular carcinoma of ovarian origin (HDFCO) [malignant struma ovarii] O. Stanowska 1 , O. Kuczkiewicz-Siemion 1 , J. Gałczyński 2 , E. Bakuła-Zalewska 3 1 Maria Sklodowska-Curie Institute - Oncology Center, Department of Pathology and Laboratory Medicine, Poland, 2 Department of Oncological Endocrinology and Nuclear Medicine, Maria Sklodowska-Curie Institute - Oncology Center, Warsaw, Poland, 3 Department of Pathology and Laboratory Diagnostics, Maria Sklodowska-Curie Institute - Oncology Center, Warsaw, Poland Background & Objectives: Struma ovarii (SO) is a monodermal teratoma with preponderance of thyroid tissue. Rarely, it undergoes malignant transformation, most often to papillary or follicular thyroid-type carcinoma. SO may present as HDFCO, which histologically resembles normal thyroid tissue or follicular adenoma but displays malignant behavior. We present a case of HDFCO with bone metastasis. Methods: 68-year old woman with thyrotoxicosis and hypertension presented with pelvic mass palpated per rectum during evaluation for constipation. Radiology tests demonstrated bilateral bulky ovarian tumours with multiple bone metastases. The patient underwent total hysterectomy and adnexectomy with histopathological examination that was not conclusive for metastases’ site of origin. Subsequent spine biopsy was prompted which resulted in detection of metastatic thyroid tissue. Total thyroidectomy was required. Results: Histopathological assessment of bilateral oophorectomy specimens revealed strumal carcinoid in mature teratoma of the left ovary (SC) and giant SO in the right ovary. Entirely submitted thyroid gland demonstrated only papillary microcarcinoma (PMC). Reevaluation of the bone biopsy excluded papillary carcinoma metastasis. Diagnosis of HDFCO was made based on microscopic appearance of bone metastasis [degenerative thyroid tissue, Thyroglobulin (+), TTF-1(+)] coexisting with struma ovarii, without presence of eutopic follicular carcinoma. PMC of the thyroid gland and SC were recognized as incidental findings. The patient remains stable under adjuvant radioactive iodine therapy with antithyroid treatment. Conclusion: Our case supports the previous reports of malignant potential of histologically benign SO and confirms that tumour with size >10 cm, thyroid tissue >80%, adhesions, peritoneal fluid and ovarian serosal rent should be evaluated as HDFCO. E-PS-08-020 Composite phaeochromocytoma with a differentiating neuroblastic component in a 71-year-old man C. Masaoutis 1 , A. Sykaras 2 , F. Dolkiras 1 , K. Stefanaki 3 , I. Provatas 1 , T. Choreftaki 4 , A. Angelousi 5 , G. Kyriakopoulos 6 1 Evaggelismos General Hospital of Athens, Greece, 2 Department of Pathology, Evangelismos General Hospital, Athens, Greece, 3 Aghia Sofia Children's Hospital, Greece, 4 Department of Pathology, General Hospital of Athens "G. Gennimatas", Athens, Greece, 5 1st Department of Internal Medicine, Laiko University Hospital, National and Kapodistrian University of Athens Medical School, Athens, Greece, 6 Department of Biological Chemistry, Medical School, National and Kapodistrian University of Athens, Athens, Greece Background & Objectives: A 71-year-old man was subjected to right adrenalectomy due to an asymptomatic adrenal tumour measuring 3,7 cm in greatest diameter. Methods: Light microscopy and immunohistochemistry. Results: Microscopy revealed a biphasic tumour, resembling a typical phaeochromocytoma to the greater extent (~80%) and a neurogenic tumour to a lesser extent (~20%). The neurogenic component consisted of centrally located nodules of ample neuropil with rare (<10%) foci of schwannian stroma and dispersed neuroblastic elements, mostly ganglion cells and neuroblasts of intermediate differentiation. Immunohistochemically, the schwannian stroma was highlighted with S100 and neuropil with synaptophysin; the neuroblastic elements stained consistently with PHOX2B, mostly with VIP, and variably with S100, synaptophysin, chromogranin and CD56; the phaeochromocytoma was positive for synaptophysin, chromogranin, CD56 and PHOX2B. Ki67/MIB-1 was detected in 1% of the nuclei of both components. Conclusion: These features are diagnostic of composite phaeochromocytoma with a differentiating neuroblastic component. The neurogenic component is usually a ganglioneuroma or a ganglioneuroblastoma; a neuroblastic component is very rare, mostly undifferentiated. The (ganglio)neuroblastic component is usually identified reliably on morphological grounds. Immunohistochemically, PHOX2B is considered the best marker for the peripheral autonomic nervous system. VIP highlights neuronal elements and its expression may be associated with functional manifestations. Surgery is curative in most cases, even with an extensive neuroblastic component. E-PS-08-021 Molecular profiling of follicular-patterned thyroid tumours in a Romanian population highlights distinct clinical, pathological and follow-up features between BRAFV600E versus RAS positive genotypes A. Nechifor-Boila 1 , A. Cota 1 , C. Banescu 2 , V. Moldovan 2 , F. Descotes 3 , M. Decaussin-Petrucci 4 , D. Piciu 5 , A. Borda 1 1 Department of Histology, UMFST Targu-Mures, Romania, 2 Department of Genetics, Center for Advanced Medical and Pharmaceutical Research, UMFST Targu-Mures, Romania, 3 Department of Biochemistry, Molecular Biology, Centre Hospitalier Lyon Sud, Hospices Civils de Lyon, Pierre Benite, France, 4 Department of Pathology, Centre Hospitalier Lyon Sud, Hospices Civils de Lyon, Universite Lyon 1, Pierre Benite, France, 5 Department of Nuclear Medicine "Ion Chiricuta" Institute of Oncology, Cluj-Napoca, Romania Background & Objectives: The aim of our study was to assess in a Romanian population the prevalence of BRAF V600E and RAS mutations in follicular-patterned thyroid tumours, and to correlate the molecular results to the clinico-pathological and follow-up data. Methods: All cases of papillary (PTC) and follicular (FTC) thyroid carcinomas registered at the Targu-Mures Pathology Department between 2008-2015, with available follow-up data were reviewed by two pathologists and re-classified into one of the following categories: conventional PTC (CPTC), follicular variant PTC (FVPTC), other variants PTC, FTC and NIFTP (non-invasive follicular thyroid neoplasm with papillary-like nuclear features). All cases were subjected to RT-PCR amplification targeting the BRAF V600E and RAS (KRAS, NRAS, HRAS) somatic mutations. Results: Our study included 165 cases: 80(48.5%) CPTCs, 14(8.5%) FVPTCs, 20(12.1%) PTC other variants, 5(3%) FTCs and 46(27.9%) NIFTPs. Among these cases, 55(33.3%) were BRAF V600E and 31(18.8%) RAS positive. The majority of BRAF V600E positive cases (92.7%) were CPTCs. Any NIFTP case was associated with BRAF V600E mutation. Compared to RAS , BRAF V600E positive tumours revealed a higher rate of multifocality (p=0.023), extrathyroidal extension (p=0.002) and lymph node involvement (p=0.001). All patients with RAS positive tumours were disease free at the last clinical assessment, compared to BRAF V600E positive patients (only 85.5%, p=0.026). Conclusion: In our study BRAF V600E and RAS positive tumours revealed distinct clinical, histo-pathological and follow-up features. Assessment of tumours’ molecular profile could play a role in a better risk-stratification of the patients in need for additional post-surgery treatment. This work was supported by the University of Medicine and Pharmacy of Targu-Mures Research Grant No. 275/1/11.01.2017. E-PS-08-022 Angioinvasive, poorly differentiated thyroid carcinoma developed on an oncocytic follicular carcinoma: report of a challenging case A. Nechifor-Boila 1 , S. Cristina 2 , R. Catana 1 , C. Carasca 3 and A. Borda 1 1 Department of Histology, UMFST Targu-Mures, Romania, 2 Department of Pathology, Targu-Mures Emergency County Hospital, Romania, 3 Department of Forensic Medicine, UMFST Targu-Mures, Romania Background & Objectives: Poorly differentiated thyroid carcinoma (PDTC) is a rare, but clinically significant entity because it accounts for most fatalities from non-anaplastic follicular cell-derived thyroid cancer. Methods: We report the case of a 68-years-old male admitted to the hospital for a large, compressive thyroid goiter. Total thyroidectomy was performed and the specimen was sent to the Pathology Department. Results: On gross examination, the left thyroid lobe was almost entirely replaced by a gray- whitish nodule of 105-mm with extensive necrosis. On microscopy, the nodule was surrounded by a thick capsule, with capsular and extensive vascular invasion. The architectural pattern was solid or trabecular, with large tumour sheets or tumour cords/ribbons, separated by thin, fibro-vascular septa. Extensive foci of endocrine-type necrosis were present in the centre of the tumour sheets. The tumour was composed entirely of oncocytic cells, with abundat eosinophilic cytoplasm and small, slightly irregular, centrally placed nuclei, with prominent nucleoli. The mitotic index was 6 mitosis/10HPF. A minor component of well-differentiated oncocytic follicular carcinoma was also observed. Immunoreactivity for Thyroglobulin was restricted to isolated tumour cells (mainly in a perinuclear dot-like pattern) or in few residual microfollicles. Immunostainning for CEA, Chromogranin and Synaptophisin were negative. A final diagnosis of angioinvasive PDTC developed on an oncocytic follicular carcinoma was set. Conclusion: The diagnosis of PDTC can be challenging, especially in oncocytic tumours. The presence of a co-existent well-differentiated component is an important morphological aid that helps and must be searched for the correct assessment of the final diagnosis. E-PS-08-023 Karyometric analysis of thyroid gland tumours D. Mihailovic 1 , Ů Mijović 1 1 Institute of Pathology, Medical Faculty, University of Nis, Serbia Background & Objectives: Papillary carcinoma is the most commonly diagnosed malignant tumour of the thyroid gland and makes 85% of all tumours of the thyroid gland. The aim of this study was karyometric analysis of papillary carcinomas and follicular adenomas of the thyroid gland. Methods: This study includes 23 tumours, 13 follicular adenomas, and 10 papillary carcinomas. The material was obtained by thyroidectomy in the Clinical Center of Niš from 2000-2017. All thyroid tumours were analysed immunohistochemically using monoclonal MIB-1 antibodies for Ki-67 antigen, and “ImageJ" software was used for karyometric analysis. After manual editing of binary images, seven nuclear parameters were estimated: nuclear area, optical density, perimeter, circularity, Feret’s diameter, integrated optical density (IOD) and Ki-67 index. For statistical analysis of the data MANOVA and t-test were used. The probability of less than 0.05 was considered statistically significant (p<0.05). Results: Nuclear size (area, perimeter, and Feret’s diameter) and IOD were significantly lower in papillary carcinoma than in follicular adenoma (p0.05). Conclusion: Our results indicate that nuclear size and IOD can be useful parameters in diagnostic pathology of thyroid tumours. E-PS-08-024 Hobnail variant of papillary thyroid carcinoma J. dos Santos 1 , R. Machado-Neves 1 , T. Amaro 1 , M. Honavar 2 1 Pathology Department - Hospital Pedro Hispano, Portugal, 2 Unidade Local de Saúde de Matosinhos - Portugal Background & Objectives: Hobnail variant of papillary thyroid carcinoma (HVPTC) is a rare and aggressive tumour defined as a papillary carcinoma (PTC) with > 30% of tumour cells with hobnail features. We report a case of HVPTC. Methods: Clinical history, macroscopic and histological features have been reviewed. Results: A 72-year-old woman with 40 mm nodule in the right thyroid lobe was submitted to fine needle aspiration: the result was papillary carcinoma. She underwent thyroidectomy: in the right lobe was a 45 mm encapsulated nodule with cystic and solid areas, yellowish and friable. Histologically, the lesion had a complex papillary and micropapillary architecture with prominent vascular cores (sometimes with foamy histiocytes) and areas with cellular discohesiveness. These papillary structures were lines by cuboidal/columnar cells with eosinophilic cytoplasm and high N/C ratio. Nuclei were apically placed, sometimes with grooves and pseudoinclusions, producing a surface bulge. These hobnail/micropapillary features were present in approximately 75% of the lesion. Microcalcification was observed. Vascular invasion was identified; there was no capsule invasion. Necrosis was absent and mitosis was scant. Immunohistochemically: TTF-1 and p53 (focal) positive. Patient was diagnosed with HVPTC pT3a Nx R0; no distant metastasis was identified. BRAF, NRAS and TERTp mutations were negative. Patient was treated with radioiodine; she is well and under clinical surveillance (10 months follow-up). Conclusion: HVPTC is a particularly aggressive and invasive tumour. Patients with this diagnosis should be observed closely for recurrent disease. E-PS-08-025 Hobnail variant of papillary thyroid carcinoma associated with a tall cell component: report of an unusual, rare case A. Borda 1 , B. Nagy 2 , E. Szasz 1 , R. Catana 1 , A. Cota 1 , A. Nechifor-Boila 1 1 Department of Histology, UMFST Targu-Mures, Romania, 2 Department of Pathology, Targu-Mures Emergency County Hospital, Romania Background & Objectives: The hobnailvariant of papillary thyroid carcinoma (HVPTC) is recognised as a new variant of PTC in the fourth edition of the WHO 2017 Classification Tumours of Endocrine Organs. Methods: We report the case of a 65-years-old female admitted to the hospital for suspicion of a thyroid malignant neoplasm. Total thyroidectomy with lymph node dissection was performed and the specimen was sent to the Pathology Department. Results: On gross examination, both the right and left lobe of the thyroid were entirely replaced by a gray-whitish tumour mass. On microscopy, the tumour exhibited complex papillary structures, lined by cells with abundant, eosinophilic cytoplasm, apically located nuclei with proeminant nucleoli and loss of cellular cohesion. This distinctive hobnail feature was associated with a “tall-cell” component: elongated, ribbon-like structures, lined by cells with abundant, eosinophilic cytoplasm, three times as tall as wide and having typical nuclear features of PTC. The tumour cells stained positive for Thyroglobulin and TTF1, which confirmed the primary origin of the tumour in the thyroid. A diagnosis of HVPTC associated with a tall-cell component was set. Extensive extrathyroid extension into strap muscles was documented. Multiple lymph node metastases, some with extra capsular extension revealing both hobnail and tall-cell-like PTC features were described. Conclusion: Although rare, HVPTC is histologically unique and important to be recognised due to its very aggressive behaviour. It can be found isolated, but more frequently associated with other aggressive histologic types of thyroid cancers, like tall-cell variant as in this case. E-PS-08-026 Testicule feminisation: a case report B. Laabidi 1,2 , R. Hedhli 3 , R. Yaich 1,2 , N. Mansouri 1,2 , F. Gargouri 4 , A. Saidi 1,2 , A. Bouziani 4 , I. Msakni 4 1 Tunis El Manar University, Medicine School of Tunis, Tunisia, 2 Military Hospital of Tunis, Department of Pathology, Tunisia, 3 Tunis El Manar University, Medicine School of Tunis Military Hospital of Tunis, Department of Pathology, Tunisia, 4 Pathology Department; Military Hospital for Instruction of Tunis, Tunisia Background & Objectives: Testicule feminisation is an X-linked disease characterised by variable defects in virilization of 46,XY individuals due to resistance to the actions of the androgen hormones, which in turn stops the forming of the male genitalia and gives a female phenotype. It occurs in one out of 20,000 births. We report the clinical and pathlogic findings in a rare case of testicular feminization. Methods: A 32-year-old woman presented with primary amenorrhea and infertility. Results: The clinical examination showed a female phenotype with normally developed breasts, normal vulva and a short vagina. Ultrasonography of pelvis showed absent uterus and hypo-echoic structure with internal vascularity in bilateral inguinal region. Testosterone was 6ng/ml. Laparoscopy showed absent uterus and presence of two pelvic masses reminiscent of ovarian structures. Bilateral gonadectomy was performed. Histologic examination of the nodules revealed two testes, with atrophy of the seminiferous tubules, insufficient development of the germinal cells with hyperplasia of the Leydig cells. No signs of testicular cancer and neither ovarian tissue were identified. Karyotyping was 46 XY. Estrogen replacement therapy was introduced. Conclusion: Testicular feminization is a rare disease that must be diagnosed and treated through collaborative interaction between gynecologists, geneticians and pathologists. Role of pathologists is to confirm the presence of atrophic tests and absence of malignancy. E-PS-08-027 Elastic fibers in papillary thyroid carcinoma microenvironment S. Rjabceva 1 , M. Derevyanko 1 , I. Siamionik 1 , M. Vorobel 1 1 Institute of Physiology of National Academy of Sciences of Belarus, Belarus Background & Objectives: The tumour microenvironment, composed of non-cancer cells and their stroma, was recognized as a one of major factor of cancer growth. The aim of this study is to estimate the changes of stromal elastic fibers in papillary thyroid carcinoma (PTC). Methods: Review of hematoxylin-eosin slides of 44 cases PTC followed by stratification into groups based on tumour size. Histochemical studies for Russell-Movat pentachrome stain was done. Results: According to tumour size all patients distributed as follows two groups: with tumour size 1.0 cm (2nd group, 18/52.9%). Thickened elastic fibers in capsule of thyroid glands was found in 13/85.3% patients of the first group and in 11/61.1% – of the 2nd group (Manna-Whitney test, p>0.05). Thickened elastic fibers around vessels was found in 6/37.5% cases of the first group and in 3/16.7% – of the 2nd (Manna-Whitney test, p>0.05). Thickened elastic fibers in tumour microenvironment were detected in 7/47.8% patients of the first group and in 2/11.1 % – of the 2nd group (Manna-Whitney test, p=0,036). Gamma`s correlation analysis revealed the associations between an increasing of thickness of elastic fibers and tumour size (r=-0.37, p <0.05). Conclusion: This study showed that the change in the thickness of the elastic fibers in PTC microenvironment is related to tumour size. Papillary thyroid microcarcinoma characterised by formed of thickened elastic fibers in tumour stroma often than PTC with more tumour size. E-PS-08-028 Searching for Hodgkin - discovering a carcinoma ex pleomorphic adenoma C. Dahlstedt-Ferreira 1 , J. Nogueira 1 , A. Galzerano 1 , J. Oliveira 1 1 Hospital Garcia de Orta, EPE, Portugal Background & Objectives: Carcinoma ex pleomorphic adenoma (Ca ex PA) is an entity arising from a benign pleomorphic adenoma, either primary or recurrent. It is a rare tumour, comprising 3,6% of all salivary gland neoplasms, more predominant in women in the sixth to eighth decades of life, affecting more often the major salivary glands. Methods: A 42 year-old male, with known classical Hodgkin lymphoma (HL) diagnosis, presented with a mobile and painless mass on his right parotid gland, which had been growing for 5 years, previously to the HL diagnosis. The subject underwent computerized tomograph, which described an intraparotideal adenomegaly, with necrosis. He was submitted to aspiration cytology and total parotidectomy. Results: Grossly, the mass measured 4x2x3cm and appeared solid, with white and yellow colour, with expansive growth. Microscopically, it presented as a biphasic tumour, having myoepithelial cells and epithelial cells with squamous differentiation and keratinization, within a condroid stroma. It had intraglandular extension and was minimally invasive, although the surgical margins were not involved by the lesion. Conclusion: Pleomorphic adenoma in the parotid gland is a benign and common entity. However, in rare cases, it can undergo malignant transformation, having an aggressive behavior, with potential to metastize in 70% of cases. However, if it is intracapsular or minimally invasive, it has a more favourable outcome, hence the importance of surgical resection of a pleomorphic adenoma before it undergoes malignant transformation. E-PS-08-029 Mixed medullary and follicular thyroid carcinoma: a rare and challenging case I. Fridrihsone 1,2 , I. Briede 1,2 , A. Abolins 1,2 , I. Strumfa 1,2 , G. Bahs 1,3 1 Riga Stradins University, Latvia, 2 Department of Pathology, Latvia, 3 Department of Internal Diseases, Latvia Background & Objectives: Mixed medullary and follicular carcinoma is a rare thyroid malignancy. To set the diagnosis, tumour must show both follicular/thyroid and medullary/C-cell differentiation by morphological features and immunophenotype. In addition, mixed pattern should be retained in metastases. Methods: Medical documentation, pathology slides and radiologic investigations were reviewed in the context of up-to-dated scientific literature. Results: A case of mixed medullary and follicular thyroid carcinoma in a 42-year-old-female is reported. TI-RADS 5 lesion by ultrasonography was suspected. Total thyroidectomy with right-sided lateral lymphadenectomy was performed. At grossing, white, firm, ill-defined lesion involved right lobe and isthmus. By histology, polygonal cells with round nuclei, coarse chromatin and amphophilic cytoplasm as well as amyloid deposits in stroma were observed. Cells were growing in nests; pseudopapillary architecture was evident focally. Both entrapped and neoplastic follicles were present, showing markedly different nuclear features. Immunohistochemically, neoplastic cells were reactive to calcitonin, CEA and synaptophysin. Expression of TTF-1 was heterogeneous by intensity, correlating with follicular morphology. Metastases in lymph nodes (12/33) showed mixed medullary and follicular morphology with marked TTF-1 expression in follicular component and positive calcitonin, CEA and low level of TTF-1 in medullary component, hence leading to diagnosis of mixed medullary and follicular thyroid carcinoma. Conclusion: Mixed medullary and follicular thyroid carcinoma is a rare thyroid tumour; thus it can be challenging, especially for young pathologist. To reach the diagnosis, awareness of the entity is important. Morphology, tumour heterogeneity and immunohistochemical findings must be considered by integrated approach, looking for correlations between morphology and immunophenotype. E-PS-08-030 Prevalence of atypical adenomas in an Algerian series of pituitary tumours F. Terkmani 1 , S. Bakhti 2 , Z.C. Amir 3 , S. Mimouni 4 1 Hospitalo University Center Mustapha, Algeria, 2 EPH Ait Idir, Algeria, 3 CHU Mustapha, Algeria, 4 CPMC, Algeria Background & Objectives: Pituitary adenomas (PA) are defined as a group of slow-growing tumours. They are most often benign controlled by surgical resection and / or specific medical treatment, nevertheless the aggressive pituitary adenoma which is characterised by an extension to adjacent structures and pituitary adenomas recurrent or resistant to medical treatment is a problem major care in current practice. The pathological classification (OMS 2017) of pituitary adenomas distinguishes the "typical" pituitary adenomas; pituitary carcinomas whereas the term of atypical adenoma is no longer recommended nevertheless it remains important to identify them with some criteria including a Ki67 □ 3% and a strong nuclear positivity for p53. Methods: The aim of this study is to evaluate the histopronotic value of Ki67 and P53 nuclear staining performed on a series of 42 atypical PA. Results: According to our results, we noted a female predominance (80%). The age of the patients in our series varies between 16 to 77 years old. The most affected age group is between 25 to 40 years old. According to the size we note a predominance of macroadenoma (64%). In our series Ki-67 revealed a degree of proliferation ≥3% in 26% of cases with a positive p53 in 20% control. Conclusion: The WHO classification (2017) took into account the "risk" presented by a pituitary adenoma with regard to recurrence or aggressiveness by integrating at the same time the size, the phenotype and the histological and / or molecular markers essential to a better stratification of this type of adenoma. E-PS-08-031 Rectal neuroendocrine tumour G2 with multiple metastatic lesions (case report) B. Güçlüer 1 , G. Kir 1 , T. Soylemez 1 1 Istanbul Medeniyet University, Department of Pathology, Turkey Background & Objectives: Primary neuroendocrine tumours (NETs) are common and neuroendocrine carcinomas (NECs) are rarely seen in the rectum. It is reported that Rectum NETs exhibit different histopathological features and clinical behaviour than other GIS NETs. A case of NET with a bland morphology showing aggressive clinical behaviour was reviewed with current data. A 71-year-old man without medical/surgical history presented with lower urinary system symptoms and rectal bleeding. Rectal examination and prostate needle biopsy was unremerkable. Colonoscopic examination revealed a 15 mm, polypoid mass in rectum. Colonoscopic biopsy was performed. Results: The tumour composed of uniform cells, arranged in alveolar pattern and with a ribbon-like pattern on microscopy. Tumour cells have round nuclei and stippled chromatin. The mitotic count was low and Ki-67 proliferation index was 3%. Necrosis was absent. The differential diagnosis inclues prostatic adenocarcinoma and NETs. The immunoprofile of this tumour showed diffuse strong positive staining for Synaptofisin, CD56, PSAP and negative staining for PSA, NKX3.1, CK7, CK20, CDX2, TTF-1, chromogranin A, calcitonin. These morphological findings and immunohistochemistry results supported a diagnosis of well differentiated NET. Metastatic foci were found in the liver, adrenal gland and iliac lymph nodes. Conclusion: In many organ systems, NETs are graded as G1, G2, or G3 based on mitotic count and/or Ki-67 labeling index, NECs are considered high grade by definition. This conceptual approach can form the basis for the next generation of NEN classifications and will allow more consistent taxonomy to understand how neoplasms from different organ systems inter-relate clinically and genetically. E-PS-08-032 Adrenocortical adenomas with concurrent adrenal myelolipomas: a single unit experience D. Di Nanni 1 , A. De Leo 2 , F. Ambrosi 3 , G. Di Dalmazi 4 , G. Zavatta 4 , V. Vicennati 4 , S. Selva 4 , C. Ceccarelli 5 , D. Santini 1 1 Pathology Unit, S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy, 2 1)Pathology Unit, Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, S. Orsola-Malpighi Hospital, Italy, 3 Pathology Unit, Sant'Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy, 4 Department of Medical and Surgical Sciences, S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy, 5 Department of Experimental, Diagnostic and Specialty Medicine, S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy Background & Objectives: The aim of the study was to analyse the clinico-pathological characteristics of the adrenocortical adenomas combined with myelolipomas. Methods: We identified 10 cases over 222 adrenalectomies collected between 2015 and 2019. For each case we reported: clinical data, macroscopic and histological features including Weiss score. Results: Among 10 cases collected, 7 were women; the patients’ age ranged from 47 to 69 years (on mean of 62 years). About clinical symptoms, 9 cases were functional adenomas (with hyperproduction of glucocorticoids in 6 cases and aldosterone in 2, mixed secretion in 1). At gross examination, the median size of the nodules was 3.8 cm (from 1.5 to 10 cm). Almost all nodules were yellowish, mostly with cystic or hemorrhagic changes. Microscopically, the tumours were composed of cords and nests of clear and / or eosinophilic cells which included adipose tissue with scattered islands of myelopoietic elements. The Weiss Score range was from 1 to 4 (median of 1.5). The median value of Ki-67 was 4.6 (from 2.5 to 5.6). Conclusion: In summary, the combination of adrenocortical adenoma with myelolipoma is not so rare as reported in literature. In the present study, it occurred mainly in adult females with clinical presentation of cortisol excess. Moreover, considering the separate embryologic origin of the adrenal cortex and medulla, these lesions could represent a form of collision tumour. E-PS-08-033 Medullary thyroid carcinoma - giant cell type S. Loxha 1 , R. Limani 2 , O. Blatnik 3 , B. Gazic 4 , I. Loxhaj 5 1 Institute of Pathology Kosovo, Kosovo, 2 Institute of Pathology Kosovo, Albania, 3 Institute of Oncology Ljubljana, Slovenia, 4 Institute of Oncology Ljubljana, Slovenia, 5 Institute of Pathology Kosovo, Kosovo Background & Objectives: Medullary thyroid carcinoma is a rare agressive tumour of the neuroendocrine origine, that arises from parafollicular C-cell. Methods: Case report Results: A 61-year-old woman with surgical spicemen of total thyroidectomy and clinical diagnosis tumour glandulae thyroidae. FNAC of the patient was malignant. Histopathology confirmed encapsulated nodular tumour 7x6.5x3.5cm, showed nests and sheets of cells with moderate to abundant cytoplasm, round and oval nuclei, large giant cells with bizarre nuclei surrounded by dense hyalinized stroma. Mitotic activity, necrosis, vascular invasion and calcificts presents. The tumour was limited to thyroid capsule. Imunichemistry examination: Calcitonin positive, CEA, Chromogranin i TTF1 positive. Conclusion: Medullary thyroid carcinoma is a rare and aggressive tumour, but morbidity and mortality remain high if untreated. It was difficult to diagnose only with H&E examination, but the appearance of imunochistochemical biomarkers Calcitonin positive, CEA positive and Chromogranin positive ,has helped us in the final diagnosis. Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-09 | Gynaecological Pathology Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-09 | Gynaecological Pathology E-PS-09-001 Malignant mixed sex cord stromal cell tumour with unusual histological appearance: a case report R. Shi 1 , C.Y. Chow 1,2 , M.A. Gudi 2 , S.H. Chew 2 , Y.C. Yeo 2 1 Singapore General Hospital, Singapore, 2 KK Women's and Children's Hospital, Singapore Background & Objectives: Sex cord-stromal tumours (SCST) are uncommon primary ovarian neoplasms. Occasionally a sex cord-stromal tumour lacks definitive characteristics of any specific tumour type and may be classified as “SCST, NOS (Not Otherwise Specified)”. Here, we report a malignant SCST, NOS, with unusual histological features. Molecular tests on recently discovered gene profiles for SCST were performed. Methods: A 68-year-old lady presented with pressure symptoms. Ultrasound showed a large hypoechoic abdominopelvic mass with lobulated appearance, coarse calcification and cystic areas measuring 14.3 x 11.1 x 7.9cm. Differential diagnoses included pedunculated fibroid and ovarian tumour. Results: Microscopically, the ovarian tumour showed a heterogeneous morphology. Focally, areas of fibroma were admixed with areas comprising fascicles of markedly atypical malignant spindle cells with brisk mitotic activity and necrosis resembling fibrosarcoma. Other areas show fibromatous background with clusters and sheets of cells showing nuclear grooves resembling fibromatous AGCT. FOXL2, TERT and DICER2 gene mutations were not demonstrated. The differential diagnoses were between sarcomatous transformation of an adult granulosa cell tumour and a malignant SCST, NOS. Conclusion: High grade malignant sex cord-stromal tumours are rare and challenging to classify. Recently, several gene mutations have been identified which may help in classification. However, in our case, these mutations were not detected. This may reflect the complex molecular pathogenesis of these tumours, especially when they undergo malignant transformation. E-PS-09-002 Intermediate vascular tumours of the female genital tract O. Oluwole 1 1 University of Abuja, Nigeria Background & Objectives: Vascular tumours of intermediate malignancy encompass a broad range of histologic entities. They are characterised clinically by having a high risk of local recurrence and limited risk of regional or distant metastasis. Vascular tumours of intermediate malignancy frequently presented in the skin often with diagnostic difficulty and are very rare in the female genital tract. Objective was to analyse the distribution of intermediate vascular tumours the female genital tract. Methods: Materials are derived from private pathology consultations and review of the literature. Results: Three patients aged (27, 33 and 35) years respectively. The sites of the tumour were two in the ovaries (right and left) and one in the cervix. The tumour was diagnosed based on routine Haematoxylin and Eosin stain as immunohistochemistry facility is not available in our center at the time of diagnosis. All the patients had surgical treatment and there was no recurrence after a year of follow-up by the attending surgeon. Conclusion: Intermediate vascular tumours in the female genital tract can present with symptoms similar to any gynaecological tumours and can lead to radical surgery. Histopathological examination is obligatory in all such cases to exclude aggressive high-grade sarcoma. E-PS-09-003 Microcystic stromal tumour of the ovary: a report of 2 cases C.Y. Chow 1 , G. Mihir 2 , S.H. Chew 2 , Y.C. Yeo 2 1 Singapore General Hospital, Singapore, 2 KK Women's and Children's Hospital, Singapore Background & Objectives: Ovarian microcystic stromal tumour is an uncommon neoplasm which was classified in the 2014 WHO Classification as a pure stromal tumour within the category of ovarian sex cord-stromal tumours. This entity was originally described as an ovarian neoplasm exhibiting a distinctive triad of histologic features with microcysts, solid cellular regions and hyalinized fibrous stroma. This neoplasm presents as a non-functioning pelvic mass. In this study, we report two cases of microcystic stromal tumour of the ovary. Methods: The first case is of a 49-year-old lady who presented with acute abdominal pain and CT scan revealed a torted right ovarian tumour. She underwent emergency right salpingo-oophorectomy. Macroscopic examination showed a 14.5cm solid-cystic tumour with large areas of haemorrhagic infarction. The second case is of a 66-year-old lady who presented with postmenopausal bleed, incidentally found to have a right ovarian complex mass on ultrasound. A 12cm solid-cystic right ovarian tumour was resected in the subsequent operation. Results: On microscopy, both tumours showed a multinodular pattern, comprising a monotonous population of tumour cells arranged in microcystic architecture. The tumour cells had bland cytologic features and stained for CD10, WT1 and β catenin, but were negative for common sex cord markers such as inhibin and calretinin. Mutational analysis of both cases revealed a missense point mutation in exon 3 of CTNNB1, as reported in the literature. There was no recurrence at the last follow up date for both cases. Conclusion: Ovarian microcystic stromal tumours are challenging to recognize due to their rarity and microcystic appearance that may raise a broad differential diagnosis. The characteristic immunophenotype and CTNNB1 mutation could serve as useful ancillary tests. It is important to be cognizant of this entity, as most of the cases are reported to have a benign clinical course to date. E-PS-09-005 Low grade endometrial stromal sarcoma - case report A. Mărcuță 1 , M. Aschie 2,1 , G.C. Cozaru 1,2 , A. Mitroi 2,1 , C. Brinzan 2,1 , T.S. Nitu 1 , R.D. Sora 1 1 Pathology Department, Emergency County Clinical Hospital of Constanta, Romania, 2 CEDMOG, "Ovidius" University of Constanta, Romania Background & Objectives: Endometrial stromal sarcomas (ESS) are rare malignant tumours accounting for about 0.2% of all genital tract malignancies, so the majority of information available in literature is based on small series or case reports. The origin and biology of stromal sarcomas are poorly understood and immunohistochemistry will help in the detection of tumour markers specific for ESS. We report a case of low-grade ESS in a 32-year-old woman who presented with a four-month history of excessive bleeding per vagina. Methods: The histopathological examination of the endometrial curettage and cervical biopsy and immunohistochemistry markers (asdesmin, h-caldesmon, oxytocin receptors, CD10, and inhibin which were useful in distinguishing cellular leiomyoma) showed an endometrial stromal sarcoma. The sample were cytogenetically analysed and the result showed an abnormal karyotype: 46,XX,t(10;17)(q22;p13)[18]/46,XX[5]. Total abdominal hysterectomy, with bilateral salpingo-oophorectomy, omentectomy and elective pelvic lymphadenectomy were then performed as a second radical surgical approach. Results: Endometrial stromal sarcomas are uncommon and their differential diagnosis from typical submucosal uterine myomas or benign endometrial polyps could be difficult. Our patient presented at 32 years, which is a rarity in itself. The hysteroscopic features of uterine sarcomas are often similar to those of endometrial polyps or submucosal myomas. It is a diagnosis that should only be made after excluding other high-grade tumours with a sarcomatous component. Conclusion: Total abdominal hysterectomy, bilateral salpingo-oopherectomy with pelvic lymphadenectomy is the optimal treatment in cases of endometrial stromal sarcomas. Research supported by CEDMOG, Ovidius University of Constanta, POS CCE 2.21. Project, (ID 1844, SMIS 48750). E-PS-09-006 Ovarian Leydig cell hyperplasia - a rare cause of virilisation T.M. Costa 1 , C. Albuquerque 1 , R. Sampaio 1 1 Centro Hospitalar Lisboa Ocidental, Portugal Background & Objectives: There are two main causes of female hyperandrogenism: ovarian or adrenal pathology. We aim to report a rare case of ovarian Leydig cell hyperplasia causing hyperandrogenism and consequent virilization of a postmenopausal woman. To the best of our knowledge there are 18 reported cases of this entity, and apart from one, all associated with masculinization symptoms. Methods: A 60-year-old woman presented increasing hirsutism and androgynous alopecia. Her past medical history included breast carcinoma at age 39, for which she underwent surgery, chemo, radio and hormonotherapy, with consequent premature menopause at age of 42. The laboratory work-up showed hyperandrogenism with total serum testosterone 85 ng/dL (normal range 2.9- 40.8 ng/dL). After exclusion of adrenal causes, a virilizing ovarian tumour was assumed and the patient underwent laparoscopic bilateral oophorectomy. Results: On gross pathological examination without particular findings. Histologically in both ovaries at the hilar region we observed ill-defined scattered small nodules of cells. These had a granular eosinophilic cytoplasm, round uniform nucleus and distinct nucleolus, consistent with Leydig cell hyperplasia. The distinction between Leydig cell hyperplasia and tumour is based on the pattern and size of the nodules. Two months postoperatively, the serum testosterone was undetectable (<2.5 ng/dL), and there was a clinical improvement. Conclusion: Besides alerting for other causes of virilization, we aim to emphasize the importance of differential diagnosis between two rare entities: Leydig Cell hyperplasia that is curative with oophorectomy, and Leydig Cell tumour that may be associated with DICER1 syndrome, and its clinical behavior is highly correlated with the histologic grade. E-PS-09-007 Endometrial stromal tumours: a clinicopathological and immunohistochemical review of three cases in a resource poor setting K. Adoke 1 , Y. Iliyasu 2 , A. Umar Adoke 3 1 Federal Medical centre Birnin Kebbi, Nigeria, 2 Ahmadu Bello University Zaria Nigeria, Nigeria, 3 Usmanu Danfodio University Teaching Hospital, Nigeria Background & Objectives: Endometrial stromal tumours (EST) were first described by Norris and taylor as a distinct group of mesenchymal neoplasms of the uterus with morphological resemblance to endometrial stroma. The current WHO classification acknowledges four categories within the endometrial stromal family of tumours namely, endometrial stromal nodule, low grade endometrial stromal sarcoma (LG-ESS), high grade endometrial stromal sarcoma (HG-ESS) and undifferentiated uterine sarcoma (UUS). We review three cases of endometrial stromal tumours. Methods: Three cases of endometrial stromal tumour diagnosed over a 1-year period (2017-2018) were retrieved from departmental archives. Blocks were stained with H&E. Immunohistochemistry was performed with three antibodies used namely CD 10, ER and PR. Results: The patient’s ages were 48, 50 and 65 years. Diagnoses was endometrial stromal nodule in the 48-year-old, LG-ESS in the 50 years old and HG-ESS in the 65 year old patient. Endometrial stromal nodule shows a circumscribe lesion composed of uniform oval small cells with scanty cytoplasm whorl around arteries. LG-ESS shows areas of myometrial invasion and mitosis was less than 3. HG-ESS showed ares of necrosis, lymphovascular invasion. All were positive for CD10, PR and ER stains. Conclusion: Endometrial stromal tumours are rare in our society. More studies need to be done to fully understand the mutations and biologic behaviour of these tumours. E-PS-09-008 Classical gonadoblastoma presenting as huge unilateral ovarian mass: an unusual presentation of a germ cell- sex cord-stromal tumour K. Adoke 1 , A. Umar Adoke 2 1 Federal Medical centre Birnin Kebbi, Nigeria, 2 Usmanu Danfodio University Teaching Hospital, Nigeria Background & Objectives: Gonadoblastoma was first described by Scully in 1953 is a mixture of germ cell tumour and sex-cord stromal tumour. It usually occurs in individuals with abnormal sexual development, indeterminate gonads with 80% been phenotypically normal women and 20% phenotypical men with undescended testicles. About 40% are bilateral. It is believed to be a precursor of germinoma. We present a rare case of gonadoblastoma in a phenotypically normal female who presented with large unilateral right ovarian mass. Methods: A 20-year-old female who was not yet married presented to the gynaecology clinic with abdominal swelling for 10 years. She was accused by her parents of having been impregnated by her boyfriend when they noticed sudden increase in the abdominal swelling in the last five months. Ultrasound reveal unilateral ovarian cyst measuring 37x32x17cm. Cyst was excised and sent for histology. Results: Gross examination shows a huge cystic specimen measuring 35x30x15cm, it contains 10 liters of clear fluid, the cyst lining showing coarse granular pale surface. Histology shows islands of germ cells admixed with sex cord stromal elements surrounded by hyalinized basement material and few calcifications. No germinoma focus was seen. Conclusion: Classical gonadoblastoma can present as a cystic ovarian mass, careful follow up of patients is necessary as the germ cell component may overgrow the stromal component resulting in dysgerminoma. E-PS-09-009 Synchronous mature teratoma and Sertoli-Leydig cell tumour in the same ovary S. Aviel-Ronen 1 , R. Barenboym 2 , B. Czernobilsky 3 1 Department of Pathology, Sheba Medical Center, Tel-Hashomer, Israel, 2 Gynaecology Department, Galilee Medical Center, Nahariya, Israel, 3 Patho-Lab Diagnostics, Ness Ziona, Israel Background & Objectives: Sertoli-Leydig cell tumour (SLCT) is a rare ovarian tumour, comprising less than 0.5% of ovarian neoplasms. Mature teratoma accounts for 20% of ovarian tumours. Both tumours have a wide age distribution but usually appear in the reproductive years. Their synchronous coexistence has been reported in less than a handful case reports. Here we describe a rare case of ovary containing both mature teratoma and Sertoli-Leydig cell tumour (SLCT). Methods: The medical records, imaging tests and pathological findings of a 77 years old patient have been studied and are presented. The patient was under ultrasonographic follow-up for about a year due to a small right ovarian cyst, 4 cm in largest dimension. Her blood levels of CA125, CA15.3, CA19.9 and CEA were within normal limit. Both her ovaries were removed laparoscopically. Results: The right ovary contained a sebaceous material filled cyst with some solid areas, representing a typical mature cystic teratoma. A separate, 1.2 cm sized well circumscribed lesion, was attached. The lesion contained closely packed tubules, surrounded by stroma. The tubule columnar cells had bland nuclei, Sertoli cells morphology and were CK and NSE positive while ER and PAX8 negative. Inhibin and calretinin stains enhanced the stromal Leydig cells surrounding the tubules. Well differentiated SLCT was diagnosed. Conclusion: Theoretically, well differentiated Sertoli-Leydig cell tissue associated with mature teratoma can reflect differentiation of the teratoma into testicular tissue. Although this possibility cannot be excluded, since the Sertoli-Leydig cell tissue was attached to the teratoma and not within it, we favor the interpretation of a rare synchronous occurrence of mature cystic teratoma and SLCT in the same ovary. E-PS-09-010 A voluminous well differentiated neuroendocrine neoplasm of the right ovary, with uncertain biological behaviour. E. Koniaris 1 , E. Moula 1 , K. Tsiardis 1 , C. Gkogkou 1 , G. Kafiri 1 1 "Hippokratio" General Hospital of Athens, Greece Background & Objectives: Ggynaecological neuroendocrine tumours (NET) are exceptionally rare lesions, with only very few reported cases in the international literature, accounting for approximately less than 0,1% of all ovarian tumours. They are a heterogenous group of separate entities, which all of them share a common feature, the expression of endocrine differentiation potential. NETs can occur in pure forms or maybe associated with other tumours and cases arising in mature cystic teratomas, have been described. Methods: A 51-year-old patient referred to our hospital with a mass in the right ovary. She underwent hysterectomy and bilateral oophorectomy. We received uterus measuring 11X8,5X6cm, left ovary m.d.: 3,2cm and right ovary measuring 14X12,5X11cm, with was completely infiltrated by whitish in hue, solid mass, with multiple cysts, mainly in central location. Immunohistochemistry: CD56 (+), Chromogranin (+), NSE (+), Synaptophysin (+/-), AE1 (+). PLAP (-), Inhibin (-), S100 (-), Calcitonin (-), SMA (-), Desmin (-), c-kit (-), ki67 (<3%). Results: Histologicaly, the tumour cells had a monotonous appearance with round nuclei, without nucleoli and an eosinophilic cytoplasm, without atypia and sparse mitosis. The neoplastic cells were arranged in bands, islands, trabecules and at places in microrossettes, as well as with few cystic spaces. Although hemorrhagic infiltrations were found, necrosis was not observed. The presence of perivascular infiltration, the vascular emboli, the cystic degeneration and the size of the tumour, suggest a degree of uncertain biological behavior related to the tumour. Conclusion: NETs are rare germ cell tumours, and many scientists classify them as teratomas with a predominance of neuroendocrine features, mainly in peri- or postmenopausal women, incidentally, found usually unilaterally, slow growing and diagnosed in early stages. Four distinct histological subtypes have been described: insular (most common), trabecular, mucinous and strumal. A third of the patients might experience carcinoid syndrome symptoms. E-PS-09-011 Endometriosis in the abdomen and pelvis A. Ilic 1,2 , M. Panjkovic 1 , T. Lakic 1,2 , M. Zivojinov 1,2 , Z. Vrekic 2 , J. Ilic Sabo 1,2 1 University of Novi Sad, Faculty of Medicine, Serbia, 2 Clinical Center of Vojvodina, Novi Sad, Center for Pathology and Histology, Serbia, Background & Objectives: Endometriosis is the condition characterised by the presence of endometrial tissue outside the uterine cavity. It is predominantly found in ovaries, uterosacral and big ligament, Fallopian tubes and intestinal tract. Intestinal endometriosis prevails in rectosigmoid junction and small bowel, usually affecting subserosa and serosa. We analysed available data of patohistological verified endometriosis in intestinal tract (age, location, clinical and patohistological diagnosis, other diseases and conditions) and compared results with results from other scientific works. Methods: Retrospective study contained 16 patient with confirmed patohistological diagnosis of endometriosis in 5 years. Data were presented in table and charts. Patohistological samples were photographed and microphotos were described and enclosed with charts. Results: The highest incidence of endometriosis (56%) is among the patients between age 31-40, followed by group of patients between age 41-50 with percentage frequency of 25% . When it comes to the most common sites of endometriosis, we talk about anterior abdominal wall (33%) and ovaries (28%), while the intestinal tract is affected in less than 5% of cases. In most cases clinical diagnosis does not match patohistological and endometriosis is not followed by additional diseases or conditions. Conclusion: Our results concerning age are in line with previous research. On the other hand, there is discrepancy in regard with localization. According to our data, endometriosis predominantly occurs in fibrous and fatty tissue in the front abdominal wall. E-PS-09-012 Glassy cell carcinoma spreading on a prolapsed leiomyoma with marked lymphatic invasion: case report S. Nagase 1 , K. Ogura 1 , K. Ashizawa 1 , M. Fukunaga 2 , T. Matsumoto 1 1 Juntendo University Nerima Hospital, Department of Diagnostic Pathology, Japan, 2 Department of Pathology, Shin-yurigaoka General Hospital, Japan Background & Objectives: Glassy cell carcinoma is a rare variant of poorly differentiated adenosquamous carcinoma and is considered to have poor prognosis. We report a case of 62-year-old nulliparous Japanese woman who presented with 73mm vaginal mass and abnormal vaginal bleeding. The mass was considered as a prolapsed leiomyoma, but since a few clusters of adenocarcinoma with serous-like morphology was shown in cytology and biopsy specimens, total hysterectomy, bilateral salpingo-oophorectomy, and pelvic lymph node dissection were performed. Methods: We recognized a poorly differentiated carcinoma spreading on the surface of a pedunculated leiomyoma evolving from the uterine isthmus. The tumour cells had enlarged nuclei and nucleoli with glassy eosinophilic cytoplasm reminiscent of glassy cell carcinoma. Moreover, carcinoma displayed prominent lymphatic invasion inside the leiomyoma although metastasis was not detected in the dissected lymph nodes. Based on the pathological findings, she underwent postoperative adjuvant chemotherapy. Results: Six-months after the operation, she was admitted to our hospital due to bowel obstruction and malignant pleural effusion. Despite the treatment, her status deteriorated and died one month after the admission. An autopsy revealed that her death was due to peritonitis carcinomatosa of glassy cell carcinoma and subsequent septic shock. Conclusion: This case exhibits an unusual infiltrating pattern of glassy cell carcinoma spreading on a prolapsed leiomyoma with marked lymphatic invasion, and as far as we know, this is the first case to be reported. E-PS-09-013 Immunohistochemical phenotype of decidual cells during ectopic pregnancy J. Krylova 1,2 , A. Drobintseva 1 , I. Kvetnoy 1 , V. Polyakova 1 , V. Korsak 3 1 D.O. Ott. Research Institute of Obstetrics, Gynaecology and Reproductology, Russia, 2 Pavlov First Saint Petersburg State Medical University, Russia, 3 International Centre for Reproductive Medicine, ICRM, Russia Background & Objectives: The process of decidualization occurs as a result of the reaction of fibroblasts of connective tissue to the action of hormones, prostaglandins, cytokines and various growth factors. Since fibroblasts are essential components of any stroma, it can be assumed that a decidual reaction in case of fertilization can take place in any organ. Aim of the study: to determine the clinical and morphological features of deciduous cells in ectopic pregnancy. Methods: Material was divided in two groups: I-decidual tissue revealed by pathohistological examination of ectopic pregnancies (6-8 weeks of gestation), II-decidual endometrial tissue of abortive material of the same gestation period. Methods . Staining with hematoxylin and eosin was carried out to determine the timing of gestation and assess inflammatory changes. Immunohistochemical reactions were performed with antibodies to Vimentin (DAKO, Denmark), LIF (Abcam, UK), PR (DAKO, Denmark) Results: Microscopic analysis of the I group in the omentum and in the ovarian cortex determined the foci of decidual transformation as an enlarged polygonal cells with eosinophilic, vacuolated cytoplasm and insignificant infiltration of lymphocytes. Immunohistochemical study revealed a positive staining of the foci of decidualization of the omentum with Vimentin, PR, LIF. The level of expression of all markers, when compared with the decidual endometrium, differed insignificantly, and was expressed mainly in the focal response to LIF. Conclusion: The omentum cells are positive to PR and can be transformed under influence of progesterone into decidia, with increasing concentration LIF, but not all cells with a decadal transformation were positive for this cytokine. What makes it possible to think about the different directions of differentiation of these cells and their functions. E-PS-09-014 Primary ovarian haemangioma - a relatively common entity incidentally discovered in an extremely unusual site A. Dumitru 1 , T. Georgescu 1,2 , C. Gavan 3 , O. Munteanu 4 , M. Sajin 5,6,7 1 Department of Pathology, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania, 2 Department of Pathology, Emergency University Hospital Bucharest, Romania, 3 4th Department of General Surgery, Emergency University Hospital Bucharest, Romania, 4 Obstetrics-Gynaecology Department of the University Emergency Hospital Bucharest, Romania, 5 SUUB, Romania, 6 UMF Carol Davila, Romania, 7 European Society of Pathology, Romania Background & Objectives: Ovarian hemangiomas are very rare benign tumours of the female genital tract with less than 60 reported cases in the scientific literature, the majority being described as isolated case reports of unusual clinical presentations or particular morphologic findings. These neoplasms occur in both adults and children with the age ranging from infancy to 81 years. Methods: We report the case of a 31-year-old woman admitted at the Emergency University Hospital in Bucharest due to severe abdominal pain. Ultrasound evaluation revealed a large uterine mass with 17 cm in its longest axis and a synchronous 2 cm cystic lesion of the left ovary. Serum tumour markers were normal. The patient underwent a total hysterectomy with left salpingo-oophorectomy. Results: Gross examination of the surgically resected specimen revealed a well-defined, intramural mass with myxoid changes and focal hemorrhagic areas located on the posterior wall of the uterine corpus. The ovarian mass was highly suggestive for endometrioma. Microscopic examination revealed an incidental mixed capillary-cavernous hemangioma. Immunohistochemical staining showed strong immunoreactivity for CD31 and CD34. Thus, the final diagnosis of primary ovarian hemangioma was established. The uterine mass was represented by a leiomyoma with myxoid changes. Conclusion: Although an uncommon entity, awareness of ovarian hemangioma's particular and diverse clinical presentation as well as its potential to imitate more common lesions such as endometriosis and other ovarian neoplasms is extremely important. Surgical removal of the involved areas and a careful clinical examination is advised because it is known that these lesions may occur in a syndromic context. E-PS-09-015 Intravascular leiomyomatosis: a case report M. Mrcela 1 , D. Milojkovic 2 , I. Stefanac 3 1 Medicinski fakultet Osijek, Croatia, 2 KBC Osijek, Croatia, 3 Primary Health Care Center Osijek, Croatia Background & Objectives: Intravenous leiomyomatosis is a rare occurrence of histologically benign smooth muscle proliferation venous spaces. Methods: A 46-year-old patient underwent hysterectomy with bilateral adnexectomy due to clinical suspicion of ovarian tumour. Tumour masses were located in the area of the parametrium, they looked solid and cystic, the solid parts were nodular, whorled appearance on the cut surface, with a longer diameter of 7 and 4,5 cm. Results: Worm-like smooth muscle proliferations were found in vascular spaces lined with vascular endothelium positive for CD31 and CD34 and negative for D2-40 both in myometrium and veins of the parametrium, where the biggest tumour masses were found. Vascular endothelial layer also was detected on the surface of smooth muscle intravascular proliferations. Conclusion: This is an illustration of unusual smooth muscle neoplasm with quasi malignant intravascular growrh. At this point, four years after surgery, our patient is alive and healthy. E-PS-09-016 Unexpected diagnosis in bilateral ovarian tumour L. Lozneanu 1 , R.A. Balan 2 , S.E. Giusca 2 , R.E. Avadanei 2 , I.D. Caruntu 1 , C. Amalinei 1 , A. Grigoras 2 1 "Grigore T. Popa" University of Medicine and Pharmacy Iasi, Romania, 2 Department of Morphofunctional Sciences I-Histology, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi, Romania Background & Objectives: Primary ovarian hydatid disease (HD) is a rare distinct entity, commonly involving liver, lung, kidney, spleen, bones, brain, and thyroid gland. HD is rarely diagnosed in pelvic organs, such as ovaries and genital tract. We report a postmenopausal female patient hospitalized for a large left ovarian tumour which had been slowly developed, along with a right ovary solid ovarian tumour, being suspected of bilateral ovarian malignancy. Methods: Routine hematoxylin and eosin, along with PAS staining, and immunohistochemistry, for CK7, CK20, Ki-67, and ER have been performed. Results: The gross specimen of right ovary showed a smooth surface, with pasty consistency and translucent bands, containing a thick mucoid material. Microscopy showed laminated eosinophilic membrane, pericystic sclerosis, collection of eosinophils, along with focal giant cell reaction, being diagnosed as a hydatid cyst. The left ovary specimen had an intact outer surface, exhibited a multilocular cystic appearance, with few inner papillae, and mucinous fluid content. The microscopic examination along with immunohistochemistry features diagnosed a concomitant mucinous borderline tumour. Conclusion: The ovarian location of echinococcosis is extremely rare but it should still be considered in any differential diagnosis of a cystic lesion, while it does not exclude a synchronous ovarian tumour. The current case highlights the necessity of a better screening of HD in endemic areas. E-PS-09-017 Clinicopathological analysis of incidentally detected blue nevi of the uterine cervix in biopsy or curettage specimens. A report of 7 cases N. Basheska 1 , B. Ognenoska-Jankovska 1 1 Department of Histopathology and Clinical Cytology, University Clinic of Radiotherapy and Oncology, Ss Cyril and Methodius University Faculty of Medicine, Republic of North Macedonia Background & Objectives: Blue nevi (BN) of the uterine cervix (UC) are rare incidental lesions; they are often found in hysterectomy specimens from middle-aged women, or rarely in specimens obtained during more conservative diagnostic procedures (e.g. biopsy, curettage). The objective of our study was to analyse the clinicopathological features of 7 incidentally detected cases of the BN of the UC in biopsy or curettage specimens. Methods: Among a total of 60 BN of the UC diagnosed on operative and biopsy specimens in our Department between 2000-2019, in 7 (7/60, 11.7%) cases BN were found in biopsy or curettage specimens that had been taken for an examination of a clinically or cytologically suspicious cervical lesion (3/7, 42.9%) or a dysfunctional uterine bleeding (4/7, 57.1%), respectively. The mean age of the patients was 44 years (range, 29-57 years). In addition to routine hematoxylin&eosin, histochemical and immunohistochemical stainings were also performed. Results: Histologically, all cases showed loose aggregates of pigmented, spindle-shaped, dendritic or nevoid, epithelioid cells in the superficial stroma in one (4/7, 57.1%) or > 2 fragments of cervical mucosa (3/7, 42.9%). The lesions ranged in size from 0.5 to 6mm (mean, 2.4mm), while their thickness ranged between 0.5-4mm (mean, 1.5mm). In one case the BN was presenting as an endocervical polyp. The pigmented cells in all tested cases were positive for melanin (Fontana-Masson), S100, Melan-A, as well as for HMB45 in 3 cases. Conclusion: Although the BN of the UC seem to be lesions of low clinical significance, they require careful differential diagnosis with other pigmented lesions including malignant melanoma, especially because they are rarely detected and might easily be missed or misinterpreted in scanty endocervical curettage or cervical biopsy specimens due to their small size, more frequent endocervical localization and occasional discrete findings. E-PS-09-018 The new approaches in research of pathomorphological aspects of endocrinopathies in obstetrics T. Pavlova 1 , A. Selivanova 1 , A. Kaplin 1 , L. Zemlianskaia 1 , E. Malutina 1 1 Belgorod State University, Russia Background & Objectives: The research of system mother- placentha-fetus in caases of endocrinopathies are still actual questions. Methods: The research of bioptates of uterus( endometrium, miometrium), placentha, umbilical cord of women with diabetes mellitus type 1(25), gestational diabetes (30), thyroid pathology( hypotheriosis (40) and diffuse toxic goiter (30)) was carried out with help of Scanning Electron Microscopy with emental analysis and atomic force microscopy. Results: It was revealed that the square of vessels at pathology was less than in control group, especially at diabetes mellitus and hypothyroidism. Folding of endothelium was significantly violates at diabetes mellitus and diffuse toxic goiter. The number of normocytes was decreased to 40,0±4,0 % at diabetes mellitus, to 42,0±5,0 % at diffuse toxic goiter, to 55,0±3,0 % at hypothyroidism and to 60,0±3,0 % at gestational diabetes(84,0±4,0% in control group). Alternative processes in stroma prevailed at diabetes and diffuse toxic goiter. Conclusion: SEM and AFM are reliable and resultative methods for research of tissues at pathology of pregnant. E-PS-09-019 Synchronous case of the primary neuroendocrine cancer of fallopian tube and serous papillary cancer of ovary N. Hyriavenko 1 , M. Lyndin 1 , S. Vladyslav 1 , O. Kravtsova 2 , D. Sumtsov 2 , D. Hyriavenko 1 , A. Romaniuk 1 1 Sumy State University, Medical Institute, Pathology Department, Ukraine, 2 Sumy Regional Clinical Oncology Center, Sumy, Ukraine Background & Objectives: Neuroendocrine tumours commonly occur in the gastrointestinal tract and lungs. They rarely were found in the genital organs. There are a few data about this neoplasia in the fallopian tubes, which is accidentally identified during the morphological study. The aim of our investigation was to demonstrate the case of the primary neuroendocrine cancer of the fallopian tube in combination with the serous papillary cancer of the ovary. Methods: The histological and immunohistochemical (СК7, СК20, СА125, ER, chromogranin А, CD56, CDX2, Ki-67) investigations were conducted for the study of the molecular peculiarities of the fallopian tube and ovary tumours. Results: The tumour growth was found in the fallopian tube wall, which is presented by trabecular structures. Immunohistochemistry showed that it was negative for СК7, СК20, СА125, ER, CDX2 and strong positive for chromogranin A and CD56. Ki-67 expression was observed in 3% of cells. In the ovary, the tumour with the formations of papillary structures, cellular atypia, as well as single psammoma bodies was present. It was CK7, CK20, CA125, ER positive and didn’t express chromogranin A, CD56 and CDX2. Conclusion: Finally, the following diagnosis was made: low-grade neuroendocrine cancer of the fallopian tube and high-grade serous papillary cancer of the ovary. This case demonstrates the possibility of the occurrence of the primary neuroendocrine cancer in the fallopian tube in combination with the serous papillary ovarian carcinoma. E-PS-09-021 Juvenile granulosa cell tumour or adult granulosa cell tumour - a diagnostic dilemma M. Kirigin 1 1 Department of Pathology and Cytology, Sestre Milosrdnice University Hospital Center, Croatia Background & Objectives: Juvenile granulosa cell tumour (JGCT) mostly occurs in young women, with wide differential diagnosis including small cell carcinoma of hypercalcemic type, desmoplastic small round cell tumour, germ cell tumours and others; however, JGCT is most commonly confused with AGCT. Methods: The ultrasound in a 16 year old girl with irregular cycles revealed a 12 cm cyst of the right ovary. The cyst was extirpated, sparing the ovary. Results: Grossly, the cyst was morselated in 2 to 5 cm fragments, with 0,5 cm thick extremely firm smooth wall. Microscopically, the wall was firm fibrous tissue containing cords and trabeculae of small, relatively uniform cells with some larger cells with clear cytoplasms, showing up to 8 mitoses/10HPF. Immunohistochemistry revealed negativity for epithelial, muscle, germ cell, lymphocytic and neuroendocrine markers. There was strong positivity for vimentin, CD99 and CD56. Inhibin and calretitin were positive only in larger cells. Reticulin fibers encircled groups of tumour cells. The conclusion was that characteristics fit the diagnosis of luteinized granulosa cell tumour. After salpingooophorectomy about 20 samples, 0.5 to 5 cm were received. Cut surface of larger samples was yellowish white with hemorrhage. Microscopically, tumour tissue showed macrofollicular and solid pattern. The immunohistochemical characteristics were the same as at first biopsy. Some solid areas contained 40 mitoses/10HPF with proliferative activity up to 50%. Small area showed classic AGCT morphology. Conclusion: JGCT and AGCT share some morphologic characteristics, and diagnostic difficulty may result when JGCT contains elements of AGCT, which was the case in our patient. E-PS-09-022 Immunohistochemical study of p16ink4α, Ki67 in combination with the study of the expression of miR-22, miR-92a and methylation of the promoter region of the WIF1 gene in the diagnosis of SIL and cervical squamous cell carcinoma E. Kogan 1 , T. Demura 1 , G. Bajramova 2 , V. Chernova 2 , L. Fajzullin 2 , N. Fajzullina 2 , V. Kiselev 2 1 First Moscow State Medical University (Sechenov University), Russia, 2 National Medical Research Center for Obstetrics, Gynaecology and Perinatology named after Academician V.I.Kulakov, Russia Background & Objectives: The purpose of the study is a comprehensive analyses of clinical, morphological, immunocytochemical data in combination with changes in epigenetic markers in the diagnosis of SIL and squamous cell carcinoma of the cervix uterus. Methods: The study included 101 patients aged 21-49 years. Group 1 - 31 patients with LSIL, group 2 - 26 patients with HSIL, group 3 - 12 patients with cervical cancer (SCC), group 4 - 32 patients with NILM. Liquid-based cytology conducted with immunocytochemical determination p16ink4α, Ki67 (DakoCytomation), histological and immunohistochemical examination of biopsies material, HPV - 21 type virus genotyping by means of RT-PCR, determination of the expression level of miR-22, miR-92a and miR25 by PCR and methylation status of the gene WIF1 bisulfite sequencing method. Results: It has been established that the complex use of liquid cytology, the double staining method p16ink4α / Ki67 and HPV tests qualitatively,methylation level of WIF1 and miR-92a increase the effectiveness of early diagnosis of SIL and SCC. Conclusion: Considering our results, a comprehensive study of p16ink4α, Ki67 in combination with the study of miR-22, miR-92a expression and methylation of the promoter region of the WIF1 gene can be considered as a potential diagnostic and prognostic marker for cervical carcinogenesis. E-PS-09-023 Uterine inflammatory myofibroblastic tumour: report of 2 cases and literature review A. Rolim da Paz 1 , J. Pires de Andrade 2 , I. De Castro Gomes 3 , S. Furtado Roberto 4 , T. Lopes de Medeiros 3 , E. Moreira de Queiroga 2 , A. Furtado Honório Dornelas 2,3 1 University Hospital Lauro Wanderley/EBSERH/UFPB, Brazil, 2 Cancer Hospital Napoleão Laureano, Brazil, 3 University Hospital Lauro Wanderley/EBSERH/UFPB, Brazil, 4 CLIM, Brazil Background & Objectives: We reported two patients: the first one, 35 years old, previously healthy, sought clinical care in gynaecology to insert an intrauterine device (IUD); during the hysteroscopy examination, there was a nodular image on the right lateral wall of the uterus, suggestive of a polyp, with the size of approximately 1.2 cm. The second patient is 41 years old, at the 40th week of gestation, with a subserosal nodule, measuring 5.3 cm, found during cesarean section. Methods: We used our two cases to review the current literature on the morphological, immunohistochemical and clinical behavior aspects of uterine myofibroblastic tumours, an uncommon entity in the uterus, in addition to emphasizing the importance of its differential diagnosis with other entities, especially leiomyosarcoma and endometrial stromal sarcoma. Results: Both lesions were resected and showed, at the macroscopy, white-gray tissue, sometimes elastic, sometimes gelatinous. Histopathological examination was characterised by bundles of spindle-shaped cells with nuclei containing inconspicuous nucleoli, sometimes grouped in storiform arrangements, supported by predominantly myxoid stroma with prominent fine vascular tissue and a variable inflammatory infiltrate. The neoplasia did not present with necrosis or significant mitotic activity. In the immunohistochemical study, the neoplastic cells were positive for ALK-1, HHF-35 and negative for p53 and p16. Conclusion: The IMT is considered a rare tumour of intermediate biological behavior with a small proportion of cases being able to recur or metastasize and cause death. The frequent positivity for ALK has helped in the differential diagnosis with other mesenchymal tumours, as well as offering new therapies with tyrosine kinase inhibitors for those with aggressive behavior. E-PS-09-024 Overexpression of ephrin receptor A2 in the ectopic endometrium of patients with deep infiltrative endometriosis A. Shchegolev 1 , S. Muftaydinova 1 , N. Fayzullina 1 , N. Buralkina 1 , L. Fayzullin 1 , V. Chuprynin 1 1 NMRCOGP, Russia Background & Objectives: Deepinfiltrativeendometriosis (DIE) ischaracterised by the invasion of endometriosis lesions in tissues and organs to a depth of over 5 mm and high proliferation. Ephrin receptor A2 (EphA2) has been demonstrated to critically regulate tumour cell growth, migration and invasiveness. The aim of this work was a comparative analysis of the expression level of the EphA2 receptor in the ectopic endometrium of patients with deep infiltrative endometriosis and endometrial carcinoma. Methods: All material from 22 women aged 28-45 years were studied: 4 cases of deep infiltrative endometriosis, 9 - endometrial carcinoma and 9 - endometrium of healthy women (4 - in the secretory phase and 5 - in the proliferative phase). Immunohistochemical analysis with antibodies to EphA2 (1:100, сlone SP169, Abcam, GB) was done to detect receptor expression. The results of staining of the glandular cells in the ectopic or eutopic endometrium were performed on a 4-point scale. Results: Eph A2 receptor were expressed on the cell surface region of glandular epithelial cells in human endometrium in both the proliferative (1.75 ± 0.4) and secretory phase (1.1 ± 0.1). The expression of marker was higher in ectopic endometrium of patients with deep infiltrative endometriosis (2.9 ± 0.3) than in the eutopic endometrium in the proliferative phase of healthy women (p <0.005) and was not significantly different from the data of patients with endometrial carcinoma ( 3.1 ± 0.3). Conclusion: EphA2 receptor is overexpressed in the ectopic endometrium of patients with deep infiltrative endometriosis and in the eutopic endometrium of patients with endometrial carcinoma. The obtained data makes it possible creation targeted therapy for treatment deep infiltrative endometriosis and cancer. E-PS-09-025 Features of the Vitamin D status and expression of the Vitamin D receptors in the uterine mucosa in patients with endometrial hyperplasia E. Kazachkov 1 , E. Kazachkova 1 , E. Voropaeva 1 , A. Zatvornitskaya 1 1 South Ural State Medical University, Russia Background & Objectives: Currently, there is no data on the level of serum 25(OH)D and vitamin D receptors (VDR) expression in the uterine mucosa in endometrial hyperplasia (EH). The aim is to compare the levels of serum 25(OH)D and VDR expression in the uterine mucosa in EH. Methods: We used endometrial biopsy samples obtained from 50 women and divided them into the two following groups: EH and normal uterine mucosa. We determined the level of serum 25(OH)D using chemiluminescent microparticle immunoassay (Architect i2000, USA) and VDR expression using Vitamin D Receptor antibody [C1C2] (Genetex, USA). For a morphometric analysis, we used a computerized image analyser Videotest - Morphology 5.2 (Russia) and applied non-parametric statistical methods. Results: We found the serum 25(OH)D deficiency in 56.67% of patients with EH, whereas the serum 25(OH)D level was adequate in 95% of patients with normal uterine mucosa (p = 0.04). The differences in the levels of serum 25(OH)D were not significant between groups (26.76±2.05ng/ml vs. 35.76±3.67ng/ml, respectively) (p = 0.06). In patients with EH, we noted the following types of endometrial VDR expression: diffuse (10%), focal (23,33%), and single-cell (36.67%). The rest 30% of the samples were VDR negative. In patients with normal uterine mucosa, the negative and single-cell expression types were absent, whereas the diffuse type prevailed over the focal type (70% and 30%, respectively). Conclusion: Patients with HE had serum vitamin D deficiency and a pronounced decrease in the endometrial VDR level, which possibly enhanced endometrial proliferation. E-PS-09-026 Vaginal recurrence of endometrial carcinoma could be avoided S. Stolnicu 1 , C. Terinte 2 , N. Ioanid 3 1 Department of Pathology, UMFST, Targu Mures, Romania, 2 Department of Pathology, Oncologic Institute Iasi, Romania, 3 Department of Surgery, Oncologic Institute Iasi, Romania Background & Objectives: The risk of vaginal recurrence in endometrial cancer ranges from 7% to 13% and has been related to various parameters (age, tumour type and grade, depth and type of myometrial invasion, presence of lympho-vascular invasion). Patients with vaginal recurrence are treated with surgery and radiotherapy. However, little is known regarding the mechanism and how to avoid the development of vaginal recurrences. Methods: A prospective study involved 7 cases of endometrial carcinoma surgically treated with classic laparotomy. In every case, 2 smears were collected from the proximal vagina around the cervix before surgery and 2 additional smears during surgery, before cutting the upper part of the vagina to remove the uterus. All smears were stained with Papanicolaou and the presence of atypical cells in the smears was corelated with the type of the tumour in every case. Results: Seven patients (range 47-72 years) presented endometrial carcinoma of polypoid type, of 3-8 cm diameter and all infiltrating the endocervix. Six cases were of endometrioid type with squamous metaplasia, while 1 case was of clear cell type. Six cases presented tumour cells in all PAP smears, while 1 case was negative before surgery, but positive during surgery. Conclusion: The data from this study suggest that in most cases the vagina is contaminated before surgery due to bleedings however, additional cases may be contaminated during surgery. We propose a change in the surgical procedure which would be easier and less costly than applying postsurgical vaginal radiotherapy. E-PS-09-027 Steroid cell tumour of ovary: a rare case report P. Tziakou 1 , E. Delliou 2 , V. Papamichail 3 , A. Zizi-Sermpetzoglou 1 1 Department of Pathology of Tzaneio General Hospital of Piraeus, Greece, 2 Laboratory of Pathology - Xanthi, Greece, 3 Laboratory of Pathology "ISTODOMI" - Piraeus, Greece Background & Objectives: Steroid cell ovarian tumours are uncommon sex cord stromal neoplasms accounting for less than 0,1%. of all ovarian tumours. Methods: We report a case of a 53-year-old postmenopausal female complaining of hair loss, deepening of voice and an unusual increase of her libido. Testosterone serum level was elevated. Ultrasonography identified a solid left ovarian mass. Bilateral salpingo-oophorectomy was performed, leading to complete resolution of symptoms and normalization of testosterone level within 1-2 months. Results: Macroscopic examination revealed an ovarian yellow solid tumour replacing almost the whole ovary. Microscopically the diagnosis of a steroid cell tumour NOS type with no cytologic atypia was confirmed. Conclusion: Stromal cell tumours are rare sex hormone secretory neoplasms, producing symptoms of virilization, particularly hirsutism. They are divided into three subtypes: stromal luteoma arising from ovarian stromal cells, Leydig cell tumour from Leydig cells in the hilum of the ovary and steroid cell tumour not otherwise specified (NOS). The last subtype accounts for 60% of all and has malignant clinical behaviour in 25-45%. Histologically the tumour cells arrange in nests, columns or cords. They are polygonal-round, with eosinophilic, clear or vacuolated cytoplasm, with central nuclei and prominent nucleoli. The absence of Rienke's crystals differentiate the tumour from Leydig cell neoplasms. Sensitive immunohistochemical markers are inhibin and calretinin and positive markers are CD99, cytokeratin, S100p. Hayes and Scully identified five pathological characteristics of malignancy:1) two or more mitoses/10HPF 2) necrosis 3) hemorrhage 4)tumour diameter>7cm and 5)grade 2 or 3 nuclear atypia. Bilateral salpingo-oophorectomy is a safe therapy option. E-PS-09-028 The role of anti-mullerian hormone in pathogenesis of endometriosis E. Kogan 1 , N. Paramonova 1 , T. Semeryuk 1 1 First Moscow State Medical University (Sechenov University), Russia Background & Objectives: Anti-mullerian hormone (AMH) is a significant regulator of a female reproductive function. The study of AMH expression may help to clarify the pathogenesis of several ggynaecological diseases including endometriosis. Aim. To evaluate expressions of AMH and AMH receptors 2 (AMHR2) in patients with deep infiltrative endometriosis. Methods: The study was performed on the surgical materials and material of endometrial samples, which were recieved from 36 women diagnosed with infiltrative endometriosis of rectovaginal septum and vagina and from 34 women diagnosed with combined infiltrative endometriosis of rectum, rectovaginal septum and vagina. The control group consists of 20 women with local peritoneal endometriosis. Expression levels of AMH and AMHR2 was identified by immunohistochemistry analysis of epithelium and stroma cells of heterotopic and eutopic endometrium. Results: Expression of AMH and AMHR 2 was significantly lower in stromal cells of endometriosis than in stromal cells of eutopic endometrium. Decrease in AMH and AMHR2 levels was found in stromal cells of eutopic endometrium as a sign of endometriosis progression. Conclusion: Reduced expression of proapoptotic substances such as AMH and AMHR2 in eutopic endometrium and local endometriosis creates favorable conditions for spreading and engraftment of heterotopiс endometrium as well as for progression of endometriosis. This finding may be one of the important links to pathogenesis of endometriosis. E-PS-09-029 Clear cell carcinoma of the endometrium: evaluation of eight cases M. Ozsen 1 , F. Oz Atalay 2 , Y. Cakir 1 1 Erzurum Regional Training and Research Hospital, Turkey, 2 Uludag University Faculty of Medicine, Turkey Background & Objectives: Clear cell carcinoma (CCC) constitutes 2% of endometrial carcinomas. It is an estrogen-independent histological subtype and included in type II (non-endometrioid) endometrial carcinoma group. The aim of this study is to present the clinicopathological features of these tumours, which are relatively rare in routine pathology practice but should be considered in the differential diagnosis because they have a worse prognosis than endometrioid carcinoma. Methods: In this study, haematoxylin and eosin stained slides of CCC cases and electronic archive records were reviewed, diagnosed between 2005-2018 in our department. Cases were evaluated retrospectively considering age and clinicopathological features such as tumour size, myometrial invasion depth, infiltration pattern, different pattern of differentiation, lymphovascular invasion, stromal reaction, necrosis, cervical stromal involvement, metastasis, and stage. Results: A total of eight cases were diagnosed as CCC in hysterectomy specimens. The mean age of patients was found to be 61.3 (range: 52-72). The histopathological evaluation revealed papillary, tubulocystic or solid patterned tumours showing polygonal, cuboidal, hobnail, and flat-shaped cells, some with eosinophilic granular cytoplasms. In one case, carcinoma was observed in endometrial polyp while no relationship was observed with polyps in others. Conclusion: CCC is a relatively rare type of endometrial carcinoma. It is important in terms of differential diagnosis of serous carcinoma, secretory type endometrioid carcinoma or endometrioid carcinoma with clear cell changes, endometrioid carcinoma with glycogen-rich squamous metaplasia areas, reactive atypia with hobnail cell metaplasia, and Arias-Stella reaction, as well as in terms of treatment and follow-up. E-PS-09-030 Association of epithelial neoplasias of the uterine cervix with non-neoplastic processes M. Shushval 1 , N. Kozlov 2,3 , L. Volkova 2,3 , A. Shatilova 2 , A. Akimova 2 , A. Antishina 2 , A. Kapustina 2 1 Baltic Federal University, Russia, 2 Immanuel Kant Baltic Federal University, Kalinigrad, Russia, 3 Lab. of Immunohistochemistry and Pathology Diagnostics, Russia Background & Objectives: Investigations of background and precancerous processes for epithelial neoplasia of uterine cervix are necessary for understanding of mechanisms of tumour transformation and progression. The study aimed to evaluate association between non-tumour pathology and neoplasia of the uterine cervix. Methods: Retrospective analysis of clinico-morphological characteristics of uterine cervix neoplasia in 205 women (2017-2018 years, surgical material) for evaluation of association between non-tumour pathology and malignancies. Age of patients: 21 -81 years. Results: The main cervical neoplasias were found: 1) CIN III (95/46.3%); 2) carcinoma in situ CIS (37/18 %); 3) invasive squamous cell carcinoma of different grade (73/ 35.7%). The prevalence of age groups of women with cervical neoplasias was found: 1) CIN III - 21-40; 2) CIS – 21-50; 3) invasive carcinoma – 31-60 and more. Anamnesis of women: 1) quantity of abortions – CIN III (non/43.2 %), CIS (1-2/51.4%), ISCC (3 and more/ 40%); 2) inflammatory processes with or without association with cervical erosion/ectopy - CIN III (62.1 %), CIS (54 %), ISCC (73.9 %); 3) ovarian cysts and uterine leomyomas - CIN III (27. 4 %), CIS (35.1 %), ISCC (31.6 %); 4) HIV and hepatitis B or C - CIN III (4.3 %), CIS (10.8 %), ISCC (2.8 %). Conclusion: Tendency of association between epithelial neoplasias of the uterine cervix and quantity of abortions and labors, inflammatory processes, ovarian cysts and uterine leiomyomas in anamnesis of women with HSIL and invasive squamous cell carcinoma was revealed, in some cases HIV and hepatitis B/C also were described. E-PS-09-031 Primary peritoneal müllerian adenosarcoma: report of a case L. Barona García 1 , E. Iborra Lacal 2 , M.I. Oviedo Ramírez 1 , A. Salazar Nicolas 1 , M.I. Ortuño Moreno 1 , A. Caballero Illanes 1 , G. Ruiz García 1 , E. Martínez Barba 1 1 Servicio de Anatomía Patológica. Hospital Clínico Universitario Virgen de la Arrixaca, Spain, 2 Hospital Clínico Universitario Virgen de la Arrixaca, Spain Background & Objectives: Mullerian adenosarcoma (AS) is a rare mesenchymal and epithelial neoplasm of low malignant potential typically arising from the uterine corpus in perimenopausal or postmenopausal women. Extra-genital sites such as the peritoneum are extremely rare and are typically found in younger women. Methods: A 71-year-old woman with abdominal pain, dysuria and palpable abdominal mass. The computed tomography scan (CT) revealed a 20 × 15 cm pelvic mass occupying the right upper pelvic region, probably of adnexal origin. Two biopsies were performed, diagnosed as borderline ovarian serous tumour and mucinous adenofibroma. A laparotomy was performed, and a peritoneal mass arising from Douglas peritoneum was found and resected. The uterus and adnexa appeared normal. Results: Microscopic examination revealed a biphasic tumour with intimally admixed glands and prominent stroma configuring finger-like projections and imparting a leaf-like (phyllodes-like) architecture. No sarcomatous overgrowth or heterologous differentiation was found. The epithelial component was focally stratified, with mild to moderate atypia, forming a more complex pattern. Primary extrauterine mullerian adenosarcoma with 30% atypical proliferating serous tumour was diagnosed. Conclusion: The main prognosis factor of AS is the condition referred as “sarcomatous overgrowth”, when more than 25% of the tumour is composed of pure high-grade sarcoma. This is associated with aggressive clinical behavior. However, independently of sarcomatous overgrowth, extra-uterine AS has a very poor prognosis. Lastly, the diagnosis of adenofibroma should be made with caution when we have small samples, since distinguishing adenosarcomas can be a challenge. E-PS-09-032 Analysis of regional peculiarities of intraepitelial neoplastic processes of the cervix M. Shushval 1 , N. Kozlov 2,3 , L. Volkova 2,3 1 Baltic Federal University, Russia, 2 Immanuel Kant Baltic Federal University, Kalinigrad, Russia, 3 Lab. of Immunohistochemistry and Pathology Diagnostics, Russia Background & Objectives: The frequency, structure, peculiarities of cervical intraepithelial neoplasia aretaking into consideration for planning of prophylaxis, diagnostics and therapy. The aim of study - to assess the regional specificity of cervical intraepithelial neoplasia characteristics in screening cytology in Guryevsk of Kaliningad Region. Methods: The study group - examination of cytological smears of 10 511 women (age 29-69 years) in 2017- 2018in Guryevsk Central Hospital. Results: Among the women of study group following cervical pathologywas revealed: intraepithelial neoplasia- 40 cases (0.399%), squamous cell carcinoma- 2 women of age 44 and 69 years (0.019%). LSIL(23) was the more frequent in comparison to HSIL (total -17, CIN II and CIN III) without significant differencesin average age of patients ( 40 years).HPV positive results: 1) LSIL (23) - 4 (17.39%); 2) HSIL - 10 (58.82%).2 cases of hyperdiagnostics of HSIL in cytology were found after histological examination (10, 52%). Inqualitative PCR the 14 types of HPV of high oncogenic risk were found: 16, 18, 31, 33, 35, 39, 45, 51, 52 , 56, 58, 59, 66, 68.In some cases in anamnesis of women with LSIL and HSIL the following ggynaecological pathology was marked:cervicitis, erosions, endometritis, salpingo-oophoritis, bacterial vaginosis. Conclusion: The regional tendencies in characteristics of cervical intraepithelial neoplasia are described, improvement of cytological screening and description of ggynaecological pathologyin anamnesis are necessary forcorrect statistic evaluation and diagnosis and understanding of possible mechanisms of progression of cervical neoplasia. E-PS-09-033 Carcinosarcoma of the vagina: HPV typing in two malignant components D. Doutel 1 , M. Baiao 2 , D. Rosa 1 , C. Cardoso 1 , G. Fernandez 1 , J. Caldeira 1 , D. Cochicho 1 , A. Felix 3 1 Instituto Portugues de Oncologia de Lisboa Francisco Gentil, Portugal, 2 Nova Medical School - UNL, Portugal, 3 Instituto Portugues de Oncologia de Lisboa, Nova Medical School - UNL, Portugal Background & Objectives: Carcinosarcomas of the vagina are extremely rare neoplasms, with 15 cases reported, 4 of which with squamous-cell carcinoma (SCC) as the epithelial component and leiomyosarcoma as the sarcomatous component. The study of HPV DNA in both components has been used to evaluate a common clonal origin. Multiple HPV types in vaginal SCC are frequently found (11%). Our aim was to use HPV typing as a tool to identify the same cell of origin of both components. Methods: A 72-year-old woman with vaginal bleeding, submitted to a hysterectomy with bilateral adnexectomy for “leiomyomas” 30 years before. Vaginal examination found an exophytic tumour with 6 cm. MRI distinguished two components: an outer component that showed restriction in diffusion weighted imaging and also contrast enhancement; and a inner component with signal characteristics of higher cellularity. Vaginal cytology identified High-Grade Squamous Intraepithelial Lesion and HPV70. A local wide excision was performed and adjuvant chemo and radiotherapy used. She is alive without evidence of disease ten months after. Results: The histopathological study revealed a biphasic neoplasm with two components: an invasive SCC (predominantly in-situ) and a leiomyosarcoma. Both components were isolated from the paraffin blocks and the HPV typing was done using INNOLipa® separately, which showed HPV70 and HPV16 in the epithelial and mesenchymal component, respectively. Conclusion: The presence of two different HPV types is puzzeling and it has not been described before in vagina carcinosarcomas, but allows to infer that the sarcomatous component is derived from an epithelial cell as HPV16 strictly infects epithelial cells. E-PS-09-034 Placental site trophoblastic Tumour: a case report D. Anestakis 1 , C. Tsompanidou 2 , M.I. Givannakis 3 , E. Chatzifotiou 1 , E. Kalyva 4 , C. Charalampidis 5 1 Department of Autopsy Histopathology, Lab. of Forensic Medicine and Toxicology, Aristotle University of Thessaloniki, Greece, 2 Department of Pathology, General Hospital of Thessaloniki "Agios Dimitrios" , Greece, 3 Surgical Department , General Hospital "AHEPA", Thessaloniki Greece, 4 Thessaloniki Forensic Service, Thessaloniki, Greece, 5 Department of Anatomy, Democritus University of Thrace, Greece Background & Objectives: Placental Site Trophoblastic Tumour is a rare variant of gestational trophoblastic disease that occur mainly in women who have history of miscarriage, termination of pregnancy or even a normal or pathological ongoing pregnancy. The clinical course is unpredictable. Methods: A 32-year-old woman eleven months following a prior full term normal pregnancy presented to the hospital with a history of two months of amenorrhea. Ultrasonography and MRI showed an ill-defined mass lesion (4,3x2,5x1,5 cm) invading the anterior wall of the uterus body. PET-CT did not detect the presence of metastasis. Laboratory test showed a slightly high level of b-HCG. Results: Therapeutic curettage was done and microscopical examination of the endometrial curettage specimen revealed a proliferation of intermediate trophoblasts that showed mild nuclear atypia, low mitotic figures (2/10 HPF) and Ki67 proliferation index 6%. These cells were positive for inhibin-A. In addition, some multinucleated cells are present. Chorionic villi and cytotrophoblasts were not identified. So, the diagnosis of Placental Site Trophoblastic Tumour was elected. Total hysterectomy was performed and microscopical examination from the mass was similar to that described in the curettage specimen with infiltration of 75% of the myometrium. Conclusion: Recognition of these very rare cases might help surgeons to predict the behaviour of the tumour and to determine the specific therapeutic approach for this patient. E-PS-09-035 Case report of a Krukenberg tumour during pregnancy G. Panselinas 1 , I. Efstratiou 1 , S. Pervana 1 , E. Pazarli 1 , O. Batsi 1 , E. Massa 1 1 General Hospital Papageorgiou, Greece Background & Objectives: Report of a rare case of Krukenberg tumour presenting with virilization during pregnancy Methods: A 39-year-old woman presented with bilateral adnexal masses, elevated CA-125, ascites and androgenic manifestations during pregnancy. The differential diagnosis included Krukenberg tumour, a sex cord stromal tumour of the ovary and a pregnancy luteoma. Gastric biopsies did not show any evidence of malignancy. The pregnancy was interrupted at 21 st week and surgery was performed. Frozen sections from the ovarian tumours showed diffuse infiltration of both ovaries by signet ring cells arranged individually or in clusters. Results: An intraoperative diagnosis of Κrukenberg tumour was made and the patient underwent bilateral salpingoophorectomy which confirmed the diagnosis by the consequent routine histologic and immunohistochemical studies . Gastroscopy following the surgery revealed a signet ring cell adenocarcinoma. The patient was treated with chemotherapy but the tumour relapsed and the patient died one year after the surgery. Conclusion: Krukenberg tumour can present with androgenic manifestations and mimic a sex cord stromal tumour or a pregnancy luteoma of the ovary. The primary carcinoma is an often occult gastric cancer in about 2/3 of the cases. E-PS-09-036 The endometrial expression of LIF and LIFR in infertile patients with adenomyosis, myoma, uterine malformations, synechia and polyps during the window of implantation A. Asaturova 1 , I. Kozachenko 2 , N. Fayzullina 2 , A. Shchegolev 2 , L. Adamyan 2 1 FSBI 'National Center for Obstetrics, Gynaecology and Perinatology named after V.I.Kulakov' Ministry of Healthcare Russian Federation, Russia, 2 FSBI "National Center for Obstetrics, Gynaecology and Perinatology named after V.I. Kulakov" Ministry of Healthcare, Russia Background & Objectives: Adenomyosis, myoma, uterine malformations, synechia, polyps were found to have negative impact on embryo implantation. Leukemia inhibitory factor (LIF), is a molecular marker for endometrial receptivity, has an effect through the LIF receptor (LIFR) on both the embryo and the endometrium site. The aim of our study was to evaluate the endometrial expression of LIF and LIFR in patients with adenomyosis, myoma, uterine malformations, synechia and polyps during the window of implantation (WOI). Methods: Endometrium was obtained during the WOI from infertile patients of reproductive age planning IVF with adenomyosis (10 patients), myoma (10 patients), uterine malformations (10 patients), synechia (10 patients) and polyps (10 patients) before and after surgery. In the comparative group were 10 patients with tubal factor of infertility and without any uterine pathology. The LIF and LIFR expressions were measured by immunohistochemistry for protein intensity and localization. Results: The mean age of the patients was as follows: adenomyosis (35,9±0,5 years), myoma (36,2±5,2), uterine malformations (29,0±5,1), synechia (34,2±0,7) and polyps (32, 8±1,7). Patients with adenomyosis, myoma, uterine malformations, synechia and polyps showed significantly and parallel reduced LIF and LIFR expressions in the eutopic endometrium during WOI as compared with the control group. An increase in the level of expression of LIF and LIFR was observed after surgery, which correlated with positive results of IVF. Conclusion: Significant reduction of LIF and LIFR expression as markers of endometrial receptivity explains the negative impact of adenomyosis, myoma, uterine malformations, synechia and polyps on implantation processes and hence the results of IVF. E-PS-09-037 Pathology of placental circulation in prolonged pregnance A. Drobintseva 1 , V. Polyakova 1 , S. Makarenko 2 , J. Krylova 2,3 1 D.O. Ott. Research Institute of Obstetrics, Gynaecology and Reproductology., Russia, 2 Saint-Petersburg Medico-Social Institute, Russia, 3 Pavlov First Saint Petersburg State Medical University, Russia Background & Objectives: The reported frequency of postterm pregnancy is approximately 3-17% . Recent studies shown that postterm delivery is at risk of complications such as hypoxia, birth injury and even stillbirth. As the placenta ages, increased rates of placental infarction and fibrin deposition. The aim of the study was to examine the circulation system in placental tissue in prolonged pregnancy. Methods: The object of the study was placenta, the investigated groups were 41 g.w. (n=20), >42 g.w. (n=20) and 38-40 g.w. (n=20). Analysis of morphofunctional state were performed by using clinical data and morphological findings. Primary monoclonal antibodies to KISS1 (1:100, Abcam), KISS1R (1:350, Abcam), CD34 (1:100, Dako) and eNOS (1:150, Abcam) were used for IHC method. Alexa Fluor 488 and 647 (1:1000, Abcam) were taken as secondary antibodies. 3D reconstruction of vessels, analysis of diameter of capillars and comparsion of eNOS expression were made. Results: The number of placenta infarction and acute circulation injury increase sharply after 41 weeks of gestation. The average area of eNOS expression in placental villi was 2 times lower in group with 42 weeks gestational age compare to control group. Expression of KISS1 and KISS1R was elevated compare to control group. Conclusion: We assume that circulation injury established in placenta of prolonged pregnancy could lead to severe hypoxia and other fetal and neonatal risks. E-PS-09-038 Expression of signal molecules associated with generation of chronic pelvic pain in patients with endometriosis A. Drobintseva 1 , J. Krylova 1,2 , A. Andreev 1 , V. Polyakova 1 , I. Kvetnoy 1 1 D.O. Ott. Research Institute of Obstetrics, Gynaecology and Reproductology, Russia, 2 Pavlov First Saint Petersburg State Medical University, Russia Background & Objectives: Chronic pelvic pain (CPP) causes neurological changes in the dorsal horn of the spine, resulting in neurogenic inflammation of multiple pelvic viscera, hyperalgesia, dysreflexia, a lower sensory threshold and, therefore, a greater perception of pain. Endometriosis is observed in 71 to 87 percent of women with chronic pelvic pain. The aim of the study was to investigate neurotrophins and nerve associated peptides in endometriotic lesions of different localization from patients with CPP. Methods: For all patients the intensity of the pain symptoms was registered using a Visual Analogue Scale. For IHC staining were used antibodies to NGF, VIP, tyrosine hydroxylase, peripherin and synaptophysin were used. For study of spatial relationship of nerve fibers 3D reconstruction of confocal images of some cases were used. Results: All endometriotic lesions was classified corresponding to their immunohistochemical profile. We found correlation between expression of neurotrophins and nerve associated peptides and severity of CPP. Conclusion: New information about neoneurogenesis and growth direction of sensitive nerve terminal were onatained. E-PS-09-039 Evolution of white conisations at the pathological anatomy's service of the University Clinical Hospital Virgen de la Arrixaca A. Salazar Nicolas 1 , M.I. Ortuño Moreno 1 , L. Barona Garcia 1 , A. Caballero Illanes 1 , M.D. Perez Caparros 2 , N. Villa Lorente 3 , M.A. Menárguez Arnaldos 4 , G. Ruiz Garcia 1 , M.I. Oviedo Ramirez 5 , M.A. Torroba Carón 1 , E. Martinez Barba 1 1 Servicio de Anatomía Patológica, Hospital Clínico Universitario Virgen de la Arrixaca, Spain, 2 Servicio de Ginecología y Obstetricia, Hospital de Mèrida, Spain, 3 Servicio de Anestesia y Reanimación, Hospital Clínico Universitario Virgen de la Arrixaca, Spain, 4 Servicio de Urgencias, Hospital Clínico Universitario Virgen de la Arrixaca, Spain, 5 Servicio de Anatomía Patológica. Hospital Clínico Universitario Virgen de la Arrixaca, Spain Background & Objectives: In many occasions, we can find conization pieces that come to us due to high-grade lesions in previous biopsies but, once the histological study in done, there is no trace of those leions described previouysly. These conizations are calld white conizations. Many studies show that, despite being histologically confirmed in a previous CIN2-3 biopsy, in approximately 10-20% of the conizations there is absence of CIN 2-3 lesion. Methods: Conizations are analysed in the period of time from 2013 to 2017 (664 total conizations, 521 diagnostic conizations and 141 white conizations), studying the proportion of conizations considered as white before and after incorporating processing and histological improvements in the study of the samples, comparing the incidence of white conizations with respect to the data reflected in the last series published in the bibliography found. The improvements include the gynaecology and obstetrics service by sending the fresh sample instead of coagulating the piece. In the Pathological Anatomy’s service, the remitted piece is spread over a piece of cork and held it with sterile needles to maintain the anatomical position and a systematics of carving by time slots. Regarding the histological study, the LAST terminology and the complementary study with the P16 technique were implanted. Results: From 2013 to 2014, 248 conizations were made, of which, 75 were white (30.2% of the total). That was very far away from what was published in last publications. Once improvements were established in the obtaining, processing and study of the conizations since 2015, 416 conizations were made between 2015-2017, of which 66 white ones assuming 15.9% of the total, being an acceptable percentage. If we look at the data per year, we see how the percentage decreases referred to white conizations: 2015 with 133 conizations and 28 white conizations (21%), 2016 136 conizations and 21 white conizations (15.4%) and 2017 were made 147 conizations being 17 considered as white ones (11.4%). Conclusion: - Achieving the conizations without electrocoagulation and sending the sample in fresh to the Pathological Anatomy service decreases the architectural distortion. - A systematic setting and carving improves the study of the piece. - Unification of the terminology used and usage of P16 technique guarantees a lower incidence of white conizations. Supported by Servicio Murciano de Salud de la Región de Murcia. E-PS-09-040 Ovarian teratomas with somatic malignant transformation: report of two cases A.P. Rodrigues 1 , J. Pardal 1 1 Hospital de Braga, Portugal Background & Objectives: Malignant transformation is a rare phenomenon in ovarian teratomas. Mature cystic teratoma is the most common ovarian neoplasm. Nevertheless, malignancy is described in 1‐2% of cases. Struma ovarii is a monodermal teratoma representing 2-5% of all ovarian teratomas. The presence of thyroid cancer in struma ovarii is even rarer, occurring in 0.5-5% of cases. We report two cases of somatic malignant neoplasm in teratomas. Methods: Case 1– A 45-year-old woman presented with abdominal pain. Ultrasonography and magnetic resonance scanning revealed an abdominal mass with 11x10x8 cm in the left uterine appendage. Case 2- A 45-year-old woman presented with a left‐sided pelvic mass on physical examination. Ultrasonography confirmed the findings, revealing a 13.4x8.7 cm mass in the left uterine appendage. Both patients underwent surgery. Results: Microscopic examination showed somatic‐type malignant lesions associated with teratomas. Case 1- A nodular area with prominent papillae was identified within struma ovarii. Histological features of papillary thyroid carcinoma were observed. Case 2- A trilineage mature cystic teratoma with a component of invasive squamous cell carcinoma was observed. The latter corresponded to a polypoid solid lesion on gross examination. Image and biochemical surveillance was the established post‐surgery approach for both patients. Both patients are alive with no evidence of disease. Conclusion: We describe two cases of unusual malignancies that can occur in daily practice. A postmenopausal setting, older age, large tumour masses and the presence of solid areas in gross examination are important clues that should raise the possibility of malignant transformation. E-PS-09-041 Widespread malakoplakia of urogenital and gastrointestinal systems O. Ilhan Celik 1 , S.Y. Celik 1 , L. Tekin 1 , Y. Dere 1 1 Mugla Sitki Kocman University, Faculty of Medicine, Department of Pathology, Turkey Background & Objectives: Malakoplakia is a rare, chronic, xanthogranulomatous inflamatory disease usually encountered in urinary and gastrointestinal systems of middle-aged women. It rarely affects female genital tract. Methods: A 57-year-old woman suffering from lower abdominal discomfort, intermittent vaginal bleeding in the last 6 months was referred to gynaecology clinic. Ggynaecological ultrasound and abdominal computed tomography revealed enlargement of uterus with a heterogeneous endometrium and myometrium corresponding a malignancy. Left adnexa was also seen solid and enlarged. The uterus and the both adnexa were adherent to surrounding soft tissues. The wall of the urinary bladder and sigmoid colon were thickened asymmetrically. Also there were many enlarged lymph nodes in pelvic, mesenteric and paraaortic regions. Uterus and both adnexa were resected for frozen section examination. However, it could not allow an exact diagnosis excluding malignancy. At operation it was revealed that uterus, both adnexa, bladder, sigmoid colon, rectum, omentum were adherent to each other. Samples taken from these organs and lymph nodes were histopathologically examined. Results: Microscopically the whole uterus, ovaries, tuba uterinas and the samples taken from bladder, sigmoid colon and rectum showed dense foamy histiocytic infiltration, granuloma formations with dispersed lymphocytes, plasmocytes and neutrophils with Michaelis-Gutman bodies diagnosing Malakoplakia. Conclusion: Whilst the etiology of malakoplakia is uncertain it is believed to be associated with defective macrophage phagocytic function causing overgrowth of microorganisms because of inability of destroying of digested bacteria. Coliform bacteria have been the most common associated microorganism. The treatment includes antibiotics and surgical excision in extensive malakoplakia. E-PS-09-042 Fibroepithelial stromal polyp of labium minus O. Ilhan Celik 1 , S.Y. Celik 1 , Y. Dere 1 1 Mugla Sitki Kocman University, Faculty of Medicine, Department of Pathology, Turkey Background & Objectives: Fibroepithelial stromal polyp(FSP) is a benign mesenchymal lesion typically seen in women of reproductive age. It is generally site-specific and presents commonly in vulvovaginal region. Methods: A 38-year-old woman suffering from a mass on her labium minus was referred to gynaecology clinic. It had first been noticed 3 months earlier as a small nodule; however it had grown rapidly during the past 2 months. Physical examination revealed a soft, polypoid, painless mass with a diameter of 7cm on her right labium minus. Total surgical resection of the lesion was performed. Results: In the histopathological examination, the lesion was composed of bland mesenchymal stellate, spindle shaped cells and multinucleated giant cells in a myxoid, loose fibrous stroma. No nuclear atypia or increased mitotic activity was seen. Immunohistochemical studies revealed that the cells of the lesion were positively stained with Vimentin, Desmin, Estrogene and progesterone receptors. The lesion was diagnosed as FSP. No recurrence was seen in 4 months after the resection. Conclusion: FSP (formerly known as pseudosarcoma botryoides) is a benign mesenchymal lesion that typically occur in the vulvovaginal region of women in reproductive age. It generally presents as a polypoid or pedunculated mass, usually measuring less than 5cm in diameter. It rarely causes local symptoms such as bleeding or discomfort and is known to be associated with hormonal exposure like pregnancy or usage of hormone replacement therapy. Total excision is the treatment. It rarely recurs and no lymph-node or distant organ metastasis have been reported. E-PS-09-043 Ovarian gastric type mucinous carcinoma arising in incidentally found mature cystic teratoma: a case report K.E. Kaçar 1 , I.E. Seven 1 , F. Eren 1 1 Marmara University, Turkey Background & Objectives: Mucinous carcinoma accounts for %3-4 of all primary ovarian carcinomas. Approximately %5 of mucinous tumours arise in mature cystic teratomas and most of them are benign whereas carcinoma is rare. Methods: A 26-year-old woman presented with abdominal distention and abdominal pain. A giant 26x22x12cm abdominopelvic mass extending from symphisis pubis to the sternum was palpated. MR imaging revealed a cystic dominant mass with solid component. The patient underwent an exploratory laparotomy. A large ovarian cyst was sent for intraoperative consultation, it was evaluated as borderline mucinous tumour. The tumour was sampled by one section per centimeter. The microscopy revealed mostly borderline mucinous tumour with focal areas of mucinous carcinoma with expansile type invasion. The mucinous epithelium was composed of gastric pyloric type epithelium which was CK 7 and Muc6 positive and CK20 negative. In addition to mucinous tumour one section revealed a teratoma component composed of mature ectodermal elements. Although additional sampes were taken we could not find any more teratoma foci. Results: With these features the tumour is diagnosed as a gastric type mucinous carcinoma arising in mature cystic teratoma. Conclusion: The origin of primary ovarian mucinous carcinomas is not very well documented. Although association of teratoma and mucinous tumours are well known, this association could be reported in limited cases. The reason for this could be that the teratoma component may be very focal as in our case, so increasing sample size can be helpful in determining the origin. E-PS-09-044 Squamous cell carcinoma of the uterine cervix associated with systemic sarcoidosis O. Ilhan Celik 1 , S.Y. Celik 1 , Y. Dere 1 , L. Tekin 1 1 Mugla Sitki Kocman University, Faculty of Medicine, Department of Pathology, Turkey Background & Objectives: Squamous Cell Carcinoma of the Uterine Cervix (SCC-C) is one of the most common ggynaecological cancers of women. Sarcoidosis is a systemic disease of unknown etiology characterised by the presence of noncaseating-granulomas in any organ, most commonly the lungs and intrathoracic lymph-nodes. The synchronous of sarcoidosis and a solid tumour is a rare condition. Methods: A 56-year-old postmenopausal woman complaining from swelling on her neck, vaginal bleeding, spontaneous weight loss of 20kilograms in 4 months was referred to gynaecology clinic. Pelvic examination revealed a haemorrhagic-lesion in her cervix and the histopathologic examination of the incisional biopsy of it exposed moderate-differentiated-SCC-C. The computed tomography revealed a localized lesion in her cervix uteri corresponding a malignancy and many enlarged lymph nodes in pelvic, abdominale, hilar regions of lungs, also solid nodules in lungs and the liver. Results: Submandibular(3cm) and hilar(5cm) lymph nodes were surgically excised and histopathologically diagnosed as Sarcoidosis. After the radical-hysterectomy, bilateral-salpingo-oophorectomy, pelvic lymphadenectomy, it was seen that the tumour was localized to the cervix uteri and no metastasis was present in the lymph-nodes; however, all of the pelvic lymph-nodes excised were diagnosed as sarcoidosis. She was treated with additional external whole-pelvis irradiation for SCC-C and slight immunsupression for sarcoidosis. Her lymph-nodes, lung and liver nodules regressed and SCC-C hasn’t recurred in the following year. Conclusion: It’s important to differentiate this rare coexistence from the localized sarcoid reactions in regional-lymph-nodes of solid tumours(LSR-LN-ST). Because Multisystem Sarcoidosis may need to be treated; however, LSR-LN-ST regress spontanously and don’t require treatment. E-PS-09-045 Low grade serous carcinoma with extensive mucinous differentiation mimicking seromucinous carcinoma of the ovary G. Kir 1 , T. Soylemez 1 , A. Aydin 1 1 Istanbul Medeniyet University, Department of Pathology, Turkey Background & Objectives: Low grade serous carcinoma (LGSC) is a rare tumour of the ovary. Most ovarian serous carcinomas are high grade tumours, whereas LGSC accounts for < %10 of all ovarian serous carcinomas. Methods: A 51-year-old woman with no medical/surgical history presented with lower abdominal pain. She underwent exploratory laparotomy for optimal debulking, including total abdominal hysterectomy, bilateral salpingo-oophorectomy, total omentectomy, and appendectomy. Results: On gross examination, the uterus, omentum, and appendix were unremarkable. Grossly, the left ovary measured 17×15×7.5cm with ruptured capsule, and the cut surface was solid and gray with focally hemorrhagic areas. On microscopic examination, the tumour consisted of elongated aggregates of cribriform glands. Intraluminal and intracytoplasmic mucin was detected. Tumour cells had moderate nuclear atypia. Mitotic index was lower than 12/10 HPF. The immunoprofile of this tumour showed negative staining for CK20, CDX2, CEA and diffuse strong positive staining for estrogen receptor, CK7, PAX8, CA125. Staining for WT1, vimentin, progesterone receptor was patchy with strong intensity and staining for p53 was wild type. We diagnosed as “cribriform pattern of low-grade serous carcinoma with mucinous differantiation”. Conclusion: Silva et al. reported 40 cases with LGSC. Mucin was detected either in intracytoplasmic or between the groups of tumour cells, in 31 cases. The differential diagnosis includes endometroid carcinoma with mucinous differentiation, mucinous carcinoma and seromucinous carcinoma. The morphological findings and immunohistochemistry results supported a diagnosis of cribriform pattern of LGSC with mucinous differantiation. E-PS-09-046 Uterine leiomyosarcoma and retroperitoneal paraganglioma: sporadic association or genetic syndrome? B. Simona 1 , A.C. Lisievici 2 , T.A. Georgescu 3 , F. Pop 4 1 Spitalul Universitar de Urgenta Bucuresti (SUUB), Romania, 2 Carol Davila University of Medicine and Pharmacy, Bucharest, Romania, 3 Department of Pathology, Bucharest Emergency University Hospital, Romania, 4 "Dr. Carol Davila" University Hospital of Nephrology, Romania Background & Objectives: Paragangliomas are rare neuroendocrine neoplasms arising from paraganglia, which can be sympathetic or parasympathetic. In the adrenal medulla they are called pheochromocytoma, but they can also occur in the head and neck, retroperitoneum and bladder. Paragangliomas can be sporadic, or can appear in a variety of familial syndromes: von Hippel Lindau, MEN 2A and 2B, Carney-Stratakis syndrome or associated with SDH mutation. Nonetheless, to our knowledge, there are no reports of the association between extra-adrenal paraganglioma and uterine leyomiosarcoma. Methods: We report the case of a 65-year-old female, who first presented to our clinic in September 2018 and underwent surgery for uterine leiomyosarcoma. In March 2019, a postoperative control CT scan revealed a retroperitoneal mass in direct contact with the transverse colon and the lesser curvature of the stomach. The tumour had a diameter of 15 cm, but did not encompass large abdominal vessels. The patient underwent surgery and the resected specimen was sent to the Department of Pathology. Results: Histopathological examination revealed a trabecular and nested proliferation of cells separated by fibrovascular septae, featuring finely granular cytoplasm and stippled nuclear chromatin. We identified areas of hemorrhage and comedonecrosis, but no invasion of lymphovascular spaces, gastric or bowel wall. The tumour revealed a Ki-67 proliferative index of 7% and diffuse reactivity for Chromogranin and NSE. The surrounding sustentacular cells were positive for S-100. SDHA and SDHB were not evaluated due to the lack of these markers in our lab. Conclusion: Coexistence of paraganglioma with other tumours is usually described in rare syndromes, such as Carney triad, a non-hereditary condition which also encompasses gastrointestinal stromal tumour and pulmonary chondroma. Similar associations with other tumours have also been described. To our knowledge, this is the first case report of extra-adrenal paraganglioma associated with uterine leiomyosarcoma and we believe that this occurrence may not be fortuitous and worthy of further investigation. E-PS-09-047 A rare entity; ovarian lipoma S.Y. Celik 1 , O. Ilhan Celik 1 , Y. Dere 1 , L. Tekin 1 1 Mugla Sitki Kocman University, Faculty of Medicine, Department of Pathology, Turkey Background & Objectives: Ovarian Lipoma is a very rare lesion. Most of the lipomatous lesions of ovary are reported as a part of teratoma. However, this case was not associated with a teratoma or any other lesions. Methods: While a 31-year-old woman was in follow up for pregnancy, an exophytic, nodular, 2 cm lesion in the left ovary was identified by ultrasound examination. The other parts of the ovary seemed normal. During the operation of cesarean this lesion was totally excised preserving the rest of the ovary. Results: In the histopathological examination the lesion was completely composed of benign, mature, monomorphic lipocytes constituting solid sheets. The lesion was encapsulated in the parenchym of the ovary. It did not include any other tissues of different origin. So the lesion was diagnosed as Ovarian lipoma. No recurrence or lymph node, distant organ metastasis were seen in 6 months after the resection. Conclusion: Lipoma is the most common benign tumour of the soft tissues. It is composed of benign, mature, uniform lipocytes and has a thin fibrous capsule seperating it from the surrounding tissues. However, lipoma of the ovary is a very rare entity. Lipomatous lesions are generally defined as associated with teratomas, lipid cell tumours and lipoleiomyomas. As it is a benign tumour total excision is the treatment. It rarely recurs and no lymph node or distant organ metastasis have been reported. So it is important to recognise it in order to protect the rest of the ovary from excision. E-PS-09-048 Persistent vaginal melanoma as an unusual mimic in the endocervix I. Busmanis 1 , D. Seow 1 1 Singapore General Hospital, Singapore Background & Objectives: Primary vaginal melanoma of the cervix is exceedingly rare, accounting for <3% of vaginal malignancies and <0.3% of all melanomas. Methods: Case Report Results: A 61-year-old Chinese female initially presented with a 3cm vaginal polyp, diagnosed as melanoma, and found to harbour a c-kit mutation. Two years later she presented with recurrent disease manifest as vaginal and vulval melanoma-in-situ, synchronously with gastric bleeding from a biopsy proven 7cm gastric metastasis of melanoma. Ten months later further vaginal bleeding necessitated a THBSO and partial vaginectomy/vulvectomy. Examination revealed multiple nodular metastases within the vaginal wall, up to 1.4cm, associated with vascular emboli, and separate foci of primary vulval melanoma-in-situ, lentiginous type. A unique feature in the cervix was colonisation within intact endocervical glands by highly pleomorphic melanoma cells, situated near to small stromal metastatic deposits. Six months later inexorable disease resulted in eventual death. Conclusion: Histologically, the most common subtype of primary vaginal melanoma is nodular subtype, followed by mucosal lentiginous. If the tumour is amelanotic, awareness of the possibility must be maintained in order to apply appropriate immunostains, and not misdiagnose a poorly differentiated tumour as squamous, or adenocarcinoma, small cell carcinoma, or leiomyosarcoma. The unique feature of this case is the first known situation of melanoma potentially mimicking endocervical adenocarcinoma-in-situ on solely histologic grounds, but in the background of recurrent multifocal metastatic, and primary disease. E-PS-09-049 Utility of p16, ER, Vimentin and CEA expression in differential diagnosis between endocervical and endometrial adenocarcinoma J.H. Nam 1 , N.I. KIM 1 , Y. CHOI 1 1 Chonnam National University Hospital, Republic of Korea Background & Objectives: When clinical and histopathological examination is not effective in determining the primary endocervical adenocarcinoma (ECAs) and endometrial adenocarcinoma (EMAs), immunohistochemistry (IHC) for ER, Vimentin (Vm), CEA and p16 is regularly used in practice. The aim of this study was to evaluate the performance of these 4 IHC markers in differential diagnosis between ECAs and EMAs. Methods: IHC for p16, ER, Vimentin (Vm) and CEA was performed on 17 ECAs and 34 EMAs (including 31 EMAs, 2 serous and 1 clear cell carcinomas). Results: Positivity rates of p16, ER, Vm and CEA in ECAs were 94.1%, 23.5%, 5.9% and 76.5%, respectively; those in EMAs were 16.1%, 67.7%, 71.0%, and 38.7%, respectively; those in serous and clear cell carcinomas were 100%, 0%, 66.7% and 33.3%, respectively. All endocervical adenocarcinomas except for one case demonstrated diffuse and moderate to strong p16 expression. In contrast, grade 1 endometrioid adenocarcinomas exhibited less diffuse and less intense expression with variable staining intensity. Similar to endocervical adenocarcinomas, all serous and clear cell carcinomas showed diffuse and moderate to strong p16 expression. The sensitivity and negative predictive value (96.3% and 94.1%) of p16 expression and the specificity and positive predictive value (95.7%, and 94.1%) of Vm expression in differential diagnosis between ECAs and EMAs were significantly higher than those of ER and CEA expression. Conclusion: p16 and Vm are more useful IHC markers and two-marker panel is recommended for using in differential diagnosis between ECAs and EMAs. E-PS-09-050 Morphological substrat and pathogenetic mechanisms of adhesion-related pelvic in endometriosis J. Krylova 1,2 , S. Kruglov 2 , V. Bezhenar 2 , M. Rybakova 2 1 D.O. Ott. Research Institute of Obstetrics, Gynaecology and Reproductology, Russia, 2 Pavlov First Saint Petersburg State Medical University, Russia Background & Objectives: Endometriosis is one of the most common ggynaecological pathologies with complex pathogenesis and a variety of clinical manifestations. It is prone to high frequency of relapses and development of adhesions. The aim of the study was to determine the potential of the peritoneum in infiltrative forms of endometriosis with development of adhesions. Methods: The material for the study included peritoneal samples obtained from women with infiltrative endometriosis and without endometriosis. Microscopic examination was conducted using the colors: hematoxylin and eosin, Van Gieson's stain, PAS. For IHC (1: 150, Abcam), VIP (1: 150, Abcam), tyrosine hydroxylase (1: 350, Abcam), Substance P (1: 350, Abcam), CD117 (1: 350 , Abcam), TGF beta 1 (1: 350, Abcam). Results: Microscopic examination was dominated by active foci, represented by cytogenic stroma and proliferative type glands. Endometrioid lesions had perivascular growth and pronounced neovasculogenesis, as well as perineural growth and inflammatory infiltration from moderate to severe. The immunohistochemical profile of heterotopias corresponded to the profile of the intact peritoneum and demonstrated high levels of neutrophins, proliferative activity of telocytes and fibrotic markers. Conclusion: Improving understanding of the pathogenesis of endometriosis will contribute to the search for therapeutic goals that can provide the necessary ways to treat endometriosis. E-PS-09-051 Angiosarcoma arising in recurred mature cystic teratoma of the ovary J.H. Nam 1 , N.I. KIM 1 , Y. CHOI 1 1 Chonnam National University Hospital, Republic of Korea Background & Objectives: While the most of mature cystic teratoma is benign, it may rarely undergo malignant transformation. Malignant transformation in this type of neoplasm is mostly represented by squamous cell carcinoma and sarcomas very rarely develop in mature cystic teratoma. To our knowledge, this is the ninth case of angiosarcoma arising in mature cystic teratoma. Methods: Herein, we also describe the clinicopathologic features of this unique case and the literature is reviewed. Results: The patient was an 18-year-old female with 1 week duration of repeated abdominal pain and tenderness. Her past medical history included previous bilateral cystectomy and was diagnosed with mature cystic teratoma of both ovaries 8 years ago. On physical examination, the patient had a palpable abdominal mass and was further evaluated with pelvis magnetic resonance images. The examination showed 25cm sized huge cystic mass in left ovary and 8cm sized cystic mass in right ovary. Emergency operation was performed due to left ovarian torsion. Macroscopically the left ovarian tumour consisted of red to brownish cystic mass with extensive hemorrhage and necrotic surface. The tumour measured 20.0 cm in greatest dimension. The right ovarian mass was 7.5 cm at its greatest dimension, both tumours were filled with sebaceous material and matted hair. Cytologic investigation of ascitic fluid was negative. Pathologic evaluation of the right ovarian tumour revealed mature cystic teratoma. The left ovarian mass showed mature cystic teratoma with malignant transformation to angiosarcoma. The teratomatous component consisted of ectodermal derived skin and appendages predominated with squamous epithelium and sebaceous glands. Hair follicles, cerebral cortex, mature bone tissue, adipose tissue were also present in varying proportions. While the most of the tumour demonstrated extensive hemorrhagic necrosis, microscopic examination revealed atypical cells with large hyperchromatic pleomorphic nuclei. The tumour displayed sheet like areas and numerous irregular vascular channels lined by atypical endothelial cells. Initial immunohistochemistry revealed strong membranous positivity for CD34, CD31 and nuclear positivity for ERG, FLI-1 with 80% of Ki-67 index. Diagnosis was rendered as angiosarcoma arising in mature cystic teratoma based on its histologic and immunohistochemical features. Conclusion: Angiosarcomas arising in mature cystic teratomas of the ovary are extremely rare. We experienced a case with recurred mature cystic teratoma which underwent malignant transformation during an interval of 8 years since its initial surgical treatment. Although mature cystic teratoma is a benign tumour, surgery or regular follow-up needs to be planned after due to consideration of the risk of malignant transformation. E-PS-09-052 Small cell carcinoma of pulmonary type arising in ovarian mature cystic teratoma. A case report P. Skoufogiannis 1 , S. Divani 1 , G. Kalodimos 1 , D. Koutsogiannis 1 , C. Barda 1 , A. Feritsean 1 1 General Hospital of Volos, Greece Background & Objectives: We present a small cell ovarian carcinoma of pulmonary type (SCCOPT) arising in a mature cystic teratoma (MCT) in a 62 year-old woman. SCCOPT arising in MCT is a very rare form of ovarian cancer. Methods: The patient underwent a primary debulking surgery. An intraoperative cytological examination of 25ml free intraperitoneal fluid and a touch imprint cytological analysis of the left ovarian tumour where performed.The tumour together with the uterus, the cervix and the right ovary were sent for histopathological and immunohistochemical analysis. Results: The cytology of the fluid showed evidence of metastatic disease whereas the imprint presented a poorly differentiated ovarian malignant neoplasm. The histopathology report revealed a SCCOPT arising in a 31,4 cm MCT of the left ovary. A small synchronous cystic teratoma was also found within the right ovary. Immunohistochemically tumour cells expressed: pankeratin, EMA and CD56. NSE and chromograninA were also focally positive. Synaptophysin, MelanA, calretinin, vimentin, p53, Ca125, CK7, CK20 and ER were negative. Ki67(MIB1) index of cell proliferation was ~ 70%. Conclusion: Malignant transformation of a cystic teratoma is a rare finding (1,8%). SCCOPT is an extremely rare form of ovarian cancer. Histopathology, Cytopathology as well some specific tumour markers may be useful in diagnosing correctly an unexpected ovarian malignancy. E-PS-09-053 Cross-talk between epithelial-mesenchymal transition, angiogenesis and natural killers in borderline ovarian tumours complicating pregnancy A. Asaturova 1 , M. Shamarakova 2 1 FSBI 'National Center for Obstetrics, Gynaecology and Perinatology named after V.I.Kulakov' Ministry of Healthcare Russian Federation, Russia, 2 Family Planning and Reproduction Center (Moscow), Russia Background & Objectives: Physiological changes in the mother’s body during pregnancy with the primary aim to support the fetus’s growth may also suspected to worsen the natural course of various malignancies with even poorer prognosis then in non-pregnant women. Though borderline ovarian tumours generally have an excellent prognosis, the risk of their progression during gestation remain has yet to be investigated. The purpose of this study was to assess the expression of epithelial-mesenchymal markers, angiogenesis and the extent of natural killers in samples of ovarian borderline tumours in pregnant and non-pregnant women. Methods: Twenty three samples [13 from pregnant (30,5±4,7 years) and 10 from non-pregnant women (33,6±5,8 years)] were investigated morphologically and immunohistochemically with VEGF, CD31, CD105, CD56, E-cadherin, Vimentin, Mann-Whitney test was used for statistics. Results: Serous borderline tumours were diagnosed more frequently in pregnant and in non-pregnant women. In addition we diagnosed endometrioid and mucinous borderline tumours with well-diffentiated components in both groups. CD31 expression in pregnant women was significantly higher than that in non-pregnant patients (p<0.05) with the median number of CD31 positive vessels 28 (range 12 – 68) and 11 (range 4 - 19), respectively. There were no differences in the immunoreactivity of all other markers among both groups (p>0.05). Conclusion: Borderline ovarian tumours in pregnant women were characterised by an enhanced CD31 expression compared with non-pregnant patients. The increase level of CD31 expression in pregnant women is supposed to be enhanced be pregestrone activity through progestin-dependent angiogenesis activation. We speculate that the similarity in VEGF, CD-105, E-cadgerin, Vimentin, CD56 expression in pregnant and non-pregnant women’s indicates lack of stimulation in these agents-dependent signal pathways on borderline ovarian tumours progression complicating pregnancy. E-PS-09-057 Low grade endometrial stromal sarcoma of the uterus metastasis to the right atrium and inferior vena cava as tumour thrombus after 10 years of hysterectomy: a case report M. Suntur 1 , G. Findik Guvendi 1 , O. Semerci 1 , S. Ozan Karakisi 2 , R. Bedir 1 1 Recep Tayyip Erdogan University, Department of Pathology, Turkey, 2 Recep Tayyip Erdogan University, Department of Cardiovascular Surgery, Turkey Background & Objectives: Endometrial stromal sarcoma (ESS) is a rare malignant mesenchymal tumour of the uterus. Endometrial stromal sarcoma of the uterus usually metastasis to the pelvic region. However cases showing intravascular and intracardiac metastasis even after 22 years of hysterectomy has also been reported. Here, we describe a 52-year-old woman who presented with right sided atrial mass and presumed inferior vena cava (IVC) thrombus which turns out to be an endometrial stromal sarcoma. Methods: Sections of formalin-fixed and paraffin-embedded tumour tissue were stained with hematoxylin and eosin. An immunohistochemistry was performed. Results: A 52-year-old woman was admitted to our hospital with respiratory distress. Transthoracic echocardiography revealed a mass in the IVC extends into the right atrium which reported as a thrombus. Thoracic and abdominal CT scans were also consistent with thrombus. Clinical and radiological impressions were consistent with thrombus. The patient received anti-coagulant treatment but did not respond to the treatment. A medical history revealed that the patient have had a hysterectomy 10 years ago and diagnosed with low grade endometrial stromal sarcoma. The intravascular and intraatrial mass entirely removed. On the macroscopic evaluation, a 18.5x3.2 cm tumoural mass with a tan-brown and grayish cut-surface and fish-meat like appearance observed. It borrows the shape of the vessels and atrium which it occupies. Microscopically tumour composed sheets of small monotonous cells with eosinophilic cytoplasm, round-to-oval nuclei and fine chromatin. There were concentric arrangement of tumour cells at the perivascular site of vessels. Pleomorphism and necrosis were absent. A prominent myxoid changes in the focal areas of the stroma noted. The mitotic index was low (4 mitoses/10 HPF). Immunohistochemical stain revealed that the tumour was positive with estrogen receptor, and CD10; and negative with desmin, HHV-8, CD117. Ki-67 proliferation index of the tumour was low (%2-3). With the help of the overall immunohistochemical and morphologic features case diagnosed as a low-grade endometrial stromal sarcoma. Conclusion: Endometrial stromal sarcoma makes up approximately 0.2% of all uterine malignancies and approximately 10% of all uterine sarcomas. ESS is divided into low grade and high grade on the basis of the frequency of mitoses. IVC and right atrium receives metastasis from renal cell carcinoma is a well-known fact. But ESS has also a potential to spread into IVC and right atrium. A case of ESS reoccurrence and metastasis to IVC 22 years after hysterectomy has been reported in the literature. Our case is also emphasis this important feature ESS. In the differential diagnosis of tumours of IVC and atrium endometrial stromal sarcoma also should be kept in mind both by clinicians and pathologists. E-PS-09-058 New predictive markers for benign endometrial lesions: platelet-to-lymphocyte and neutrophil-to-lymphocyte ratio S. Köseoğlu 1 , Y. Dere 2 1 Mugla Sitki Kocman University Training and Research Hospital, Department of Obstetrics and Gynaecology, Turkey, 2 Mugla Sitki Kocman University, Faculty of Medicine, Department of Pathology, Turkey Background & Objectives: Endometrial polyps (EP) and endometrial hyperplasia (EH) are the two of the most common causes of abnormal uterine bleeding. The aim of this study to evaluate the differentiation of EP and EH in patients by using NLR and PLR which are inflammatory markers. Methods: This retrospective study consists of 108 patients diagnosed with EP and 80 patients diagnosed with EH without atypia. Ten cc of venous blood sample from every patient. Hemoglobin, MCV (mean corpuscular volume), RDW (red cell distribution width), MPV (mean platelet volume), numbers of lymphocytes, neutrophils, platelets, plateletcrit. NLR end PLR values were recorded. Results: NLR values were found as 2.8□2.79 in EP group and 2.2□1.30 in EH group. (P=0.022). PLR values were 157.74□83.14 in EP group and 139.87□59.20 in EH group (P=0.024). There were significant differences in terms of PLR and NLR values. Conclusion: EH and EPs can be differentiated before the intervention with NLR and PLR which are simple, easily accessible, repeatable and inexpensive methods. E-PS-09-059 Fumarate hydratase deficient uterine leiomyoma: a case report H. Sahin Ozkan 1 , T. Oguzsoy 2 , S.F. Eren 1 1 Marmara University Faculty of Medicine, Department of Pathology, Turkey, 2 Marmara university training anad researching hospital, Turkey Background & Objectives: Hereditary leiomyomatosis and renal cell carcinoma syndrome (HLRCCS) is a rare disease caused by germline Fumarate Hydratase (FH) mutation. Here, we report a case of FH-deficient leiomyoma (FHDL) without a previously known personal and/or family history. Methods: A myomectomy specimen, diagnosed with atypical uterine leiomyoma in another medical center was sent to our pathology department for a second opinion. The patient was 33 years old. Results: Gross examination revealed two masses: 1) A 4 cm myomatous mass, 2) A myomatous mass measuring 9.5 cm with some small foci of hemorrhage. Microscopic examination of the first mass showed an ordinary leimyoma. The second mass was a smooth muscle tumour consisting of hypocellular areas with alveolar-edema and hypercellular areas. Symplastic atypia, prominent cherry-red nucleoli, peri-nuclear clearing, intracytoplasmic eosinophilic globules, and hemangiopericytomatous vessels were the most notable findings. Mitosis was 1/10 HPF. Atypical mitosis and/or necrosis were absent. Tumour cells were positive for SMA and negative for CD10 antibodies. Complete loss of FH immunexpression was found in the tumour cells. The diagnosis was FHDL. An explanatory note was added to clarify that although the most FHDLs are seen sporadically, genetic testing should be recommended if the other risk factors for HLRCCS are present. Conclusion: Uterine FHDL is a basic component of HLRCCS. While evaluating atypical leiomyomas, pathologists should bear in mind the typical histomorphological findings of FHDL. Histomorphology is superior to blind immunohistochemical screening. Approximately 1% of all uterine leiomyomas are FH-deficient, usually due to somatic inactivation. Genetic testing for HLRCCS should not be routinely recommended to the patients with FHDL in the absence of other clinical risk factors. E-PS-09-060 Uterine Mullerian Adenosarcoma: a retrospective study of 13 cases S. Ben Khalifa 1 , N. Abdessaied 1 , T. Zahmoul 2 , E. BelhajKhalifa 2 , S. Chaieb 1 , B. Atika 2 , M. Mokni 1 1 Pathology Department of Fattouma Bourguiba Hospital, Monastir, Tunisia, 2 Department of Pathology; Farhat Hached Hospital; Sousse, Tunisia Background & Objectives: Uterine adenosarcoma is a rare tumour (8% of uterine sarcomas) with a dual component: a benign glandular compartment and a sarcomatous stroma. The objective of this work is to report the clinical and pathological features of this tumour. Methods: We retrospectively analysed the clinical and pathologic data of 13 patients, initially diagnosed and treated at our institution from 1993 to 2018. Histological confirmation of the diagnosis was obtained after biopsy of the tumour or after hysterectomy. Results: The median age at diagnosis was 53 years (range, 21–69 years). The majority of patients presented with abnormal uterine bleeding (69%). On preoperative clinical examination, a polyp prolapsing through the cervix was seen in 6 patients (46%). The average tumour size was 11.2 cm (7,8 to 16 cm). Eight patients (61,5%) had stage I disease, 3 (23%) had stage II disease, 7,6 (4%) had stage III disease, and 7,6 (3%) had stage IV disease. Six patients (46%) had sarcomatous overgrowth, and 7 patients (53.8%) had tumours that contained heterologous elements. Death due to the disease was observed in 53,8% (7/13) of patients. Conclusion: Uterine adenosarcoma is rare cancer, whose diagnostic and therapeutic management are multidisciplinary as regards gynecologists, pathologists, and oncologists. This tumour is seen especially in postmenopausal patients with a polymorphic symptomatology dominated by metrorrhagia. Its prognosis remains favorable in localized forms, of which the surgery alone seems sufficient, on the other hand for the extended forms which are still controversial; Radiochemotherapy always retains their place. E-PS-09-061 Agressive angiomyxoma of the vulva: a report case S. Yacoub 1 , S. Mistiri 1 , D. Chiba 1 , T. Tlili 1 , N. Abdessayed 1 , M. Mokni 1 1 Department of Pathology Farhat Hached Hospital, Tunisia Background & Objectives: Aggressive angiomyxoma (AA) is a rare, locally aggressive mesenchymal tumour of the perineum, affecting more frequently women. its aggressiveness is local, reflecting its infiltrating character and its tendency to recurrence. We describe the clinical and pathological characteristics of an aggressive angiomyxoma of the vulva. Methods: A 40-year-old woman with no previous history, consulted for a swelling of the large right lip of the vulva. A surgical resection was performed. Results: The resected specimen showed a polypoid tumour of 5 cm long axis fixed to a pedicle of 1.3 cm. The surface was greyish without any ulcer or erosions. Histological examination showed a mesenchymal proliferation, of low to moderate cell density. It was made of stellate or elongated fibroblastic-like cells. The stroma was loose, myxoid full of capillaries and venules of variable size. There were scalloped with regular endothelial lining. The skin surface was regular, non-ulcerated. the surgical boundaries were tumour-free. Conclusion: AA is a locally aggressive rare mesenchymal tumour of the pelvis, expressing the hormone receptors. Surgical removal is the main treatment. The use of hormonal treatment during recurrences is being evaluated and shows in some cases encouraging results. E-PS-09-062 Mucinous adenocarcinoma of the uterine cervix: clinicopathological study of 8 cases M. Manai 2 , G. Sahraoui 2 , R. Doghri 1 , R. Sallami 2 , H. Guizani 2 , K. Mrad 1 , L. Charfi 1 , M. Driss 1 1 Department of Pathology, Salah Azaiez Institute, Tunisia, 2 Salah Azaiez Institute, Tunisia Background & Objectives: Adenocarcinoma is the second type of cervical cancer accounting for 20–25% of all cervical cancers. Mucinous adenocarcinoma was redefined in 2014 WHO classification into different subtypes: gatric type, intestinal type and signet-ring cell type. The aim of this study is to describe the clinicopathological characteristics of these various subtypes of cervical cancer. Methods: This was a retrospective descriptive study of patients diagnosed between 1 January 2010 and 31 December 2016 in one cancer institute. All the cases of cervical adenocarcinoma were defined as mucinous adenocarcinoma according to 2014 WHO classification. We analysed their clinical and pathological characteristics. Results: Among the 38 cases of cervical adenocarcinoma, 8 (21%) were diagnosed as mucinous. Five were intestinal type, one was of gastric type, two were signet-ring cell type. The patients’ mean age was 48 years and 6 patients were premenopausal. The revealing symptom was metrorrhagia in seven cases and (38%) and pelvic pain whose exploration revealed an ovarian mucinous tumour. No patient had a cervical smear. Six cases were negative for p16(INK4a) in immunohistochemistry. Seven patients had recurrence or metastases after initial treatment. Conclusion: Mucinous adenocarcinoma is a rare and aggressive form of cervical cancer that can be confused with other pathological types. E-PS-09-063 Primary ovarian carcinoid arising in mature cystic teratoma: case report A.C. Lisievici 1 , T.A. Georgescu 2 , M. Sajin 3,4,5 , R. Bohaltea 6 1 Carol Davila University of Medicine and Pharmacy, Bucharest, Romania, 2 Department of Pathology, Bucharest Emergency University Hospital, Romania, 3 SUUB, Romania, 4 UMF Carol Davila, Romania, 5 European Society of Pathology, Romania, 6 Department of Obstetrics and Gynaecology, Emergency University Hospital Bucharest, Romania Background & Objectives: Carcinoids are rare neuroendocrine tumours with an incidence of 1 to 2 cases per 100,000 patients. Primary ovarian carcinoids account for less than 1% of all carcinoid tumours and less than 0.1% of all ovarian neoplasms, being so rare that a clinician may not encounter even one during his or her entire medical career. Methods: We report the case of a postmenopausal 64-year-old female presenting to the Emergency University Hospital in Bucharest, Romania due to lower abdominal pain. CT examination revealed a large, well-defined, bilobed solid and cystic mass of the left ovary, with no detectable ascites. The patient underwent bilateral salpingo-oophorectomy. Results: Gross aspect of the left adnexa and subsequently examined frozen sections were suggestive for mature cystic teratoma. Careful postoperative histopathological examination of the solid areas revealed a mixed-type carcinoid (insular and trabecular) arising in the background of a mature cystic teratoma. The tumour was limited to the left ovary, without rupturing the cyst wall (T1a). Ancillary tests revealed immunoreactivity for synaptophysin, chromogranin and a low Ki-67 proliferative index (<1%). ER, PR and CDX2 were negative. The right ovary was unremarkable. Conclusion: In the absence of other teratomatous elements, primary ovarian carcinoids may be difficult to distinguish from metastatic carcinoids. Carcinoid syndrome may develop in the absence of liver metastases. Diagnosis should always be confirmed by immunohistochemistry and extensive sampling of any solid area within a mature teratoma is emphasized, in order to minimize the risk of missing a focus of carcinoid. E-PS-09-064 Hormone receptor end p16 immunohistochemical expression in distinction between endometrial and endocervical adenocarcinoma R. Narjess 1 , N. Boujelbene 2 , M. Driss 2 , R. Doghri 2 , I. Abbes 2 , H. Azaiz 2 , N. Ben Hamida 2 , K. Mrad 2 , L. Charfi 2 1 Institut of Carcinology Salah Azaiz Tunis, Tunisia, 2 Department of Pathology, Salah Azaiez Institute, Tunisia Background & Objectives: Primary endometrial (EmA) and endocervical (EcA) adenocarcinoma are recognized as distinct entities, with different etiologies, behavior and treatments. Sometimes, distinction between them is often difficult in limited diagnostic specimens such as biopsies or curettage specimens. We investigated the value of a panel of antibodies, to distinguish between primary EmA and EcA. Methods: We use a panel of immunohistochemical stains including estrogen receptor (ER), progesterone receptor (PR) and p16 in a series of cervical biopsies presenting considerable overlap in the morphological features of adenocarcinoma arising in the two sites mentioned above. Results: Twenty-eight biopsies were evaluated. They concern 20 EmA and 8 EcA. The great majority of EmA (77.7%) express ER but no case of EcA express ER (p=0.001). Likewise, PR was expressed in most EmA (73.3%) and no case of EcA (p=0.001). Seventy-five percent of EmA display variable patchy p16 expression, only 1 case show extensive p16 expression. All EcA show diffuse nuclear p16 expression (p<0.0001). Conclusion: We conclude that ER, PR and p16 are useful immunohistochemical markers in distinguishing EmA and EcA. The "classic" endometrial adenocarcinoma will be positive for ER, PR and show weak or patchy p16. In contrast, the "classic" endocervical adenocarcinoma will be strongly and diffusely positive for p16 but negative for ER, and PR. This distinction is important to make because the different therapeutic management and prognosis. E-PS-09-065 Vulvar sarcoma: a single institution experience M. Manai 1 , R. Doghri 2 , G. Sahraoui 1 , R. Sallami 1 , D. Kacem 1 , K. Mrad 2 , M. Drisse 2 , L. Charfi 2 1 Institute Salah Azaiez, Tunisia, 2 Department of Pathology, Salah Azaiez Institute, Tunisia Background & Objectives: Sarcomas of the vulva comprise approximately 1–3% of all vulvar cancers, with leiomyosarcomas, epithelioid sarcomas, and rhabdomyosarcomas being the most common among them. The aim of this study is to report our incidence of sarcoma at this site and to emphasize the broad differential diagnosis and the prognostic factors. Methods: All patients with a diagnosis of vulvar sarcoma at the department of pathology of Salah Azaiez Institue over a period of 25 years (1993 - 2018). Clinical, histopathological and immunohistochemical features were recorded. Results: Six vulvar sarcomas were diagnosed during this period: rhabdomyosarcoma (n = 2), leiomyosarcoma (n=1), epithelioid sarcoma (n=1), dermatofibrosarcoma (n=1), and carcinosarcoma (n=1). The age ranged from 2 months to 56 years. The rhabdomyosarcomas were of embryonal-type and were diagnosed at early childhood (2-16months). All the cases were clinically present as a non-specific tumour mass. The tumour size ranged from 30 to 80mm. The diagnosis was made on biopsy in all cases. Immunohistochemistry was necessary to classify these sarcomas. A vulvectomy was performed in 3 cases (Dermatofibrosarcoma, epithelioid sarcoma, carcinosarcoma) with negative microscopic margins in only one case (dermatofibrosarcoma). Chemotherapy was indicated in rhabdomyosarcomatous cases. Conclusion: Sarcomas of the vulva are rare malignant neoplasms that often lead to misdiagnosis.It is important to consider them in the clinical differential diagnosis of non-specific vulvar lesions, in order to establish an early accurate diagnosis and appropriate treatment. E-PS-09-066 RIG-1 is down regulated in placental tissue in cases of early - and late - onset preeclampsia N. Nizyaeva 1 , M.N. Nagovitsyna 1 , E.Y. Amiraslanov 1 , N.A. Lomova 1 , S.V. Pavlovich 1 1 V.I.Kulakov National Research Center for Obstetrics, Gynaecology and Perinatology of Ministry of Healthcare of the Russian Federation, Moscow, Russia Background & Objectives: The objective was to study in placental samples in cases of early–(EPE) and late – onset (LPE) preeclampsia. Methods: Groups with PE included 12 women with EPE and 8–with LPE. Control groups consist of 10 women with normal pregnancy, 38-39 gestation weeks (late control–LC), and 10 – 26-30 weeks (early control–EC). We performed histological (hem&eosin) and immunohistochemistry studies on the paraffin-embedded slices of placenta, taking after cesarean section, using RIG-1 primary polyclonal antibodies (1:500;GenTex). The intensity of immunohistochemical reaction was estimated by means of microscope imaging software NIS-Elements. Results: The immunohistochemical study indicated RIG-1 staining in placental villi: amnion cells, endothelium, decidual cells, cyto-and syncytiotrophoblast, syncytial knots, stroma cells. RIG-1 demonstrated significantly higher expression in syncytiotrophoblast (17+4) in LC group than in the other studied groups EC (8+3), EPE (9+4) and LPE (11+3), (р<0.01). Compare to LC group RIG-1 expression were at 47% higher than in EC, 52.9% higher than in EPE, and 62.7% higher than in LPE group (p<0.01). Decreased RIG-1 expression probably contributes to the development of pro-inflammatory response and PE. Conclusion: Thus, down regulated in syncytiotrophoblast RIG-1 expression in PE confirmed pro-inflammatory trophoblast phenotype and may be one of the predisposing factor for preeclampsia. Funding by the Grant of the President for leading scientific schools (NS-4566.2018.7, Agreement 075-02-2018-519). E-PS-09-068 Morphological effects of chemoradiation therapy on cervical adenocarcinoma A. Candaele 1 , J. Van Dorpe 1 , E. De Jaeghere 1 , P. Tummers 1 , A. Makar 1 , P. De Visschere 1 , H. Denys 1 , K. Vandecasteele 1 , K. Van de Vijver 1 1 Ghent University Hospital, Belgium Background & Objectives: The Study group included 10 women with a histological diagnosis of advanced cervical adenocarcinoma, receiving neo-adjuvant chemoradiation therapy followed by radical surgery. The aim for the present study is to evaluate the responsiveness to chemoradiation and to identify pathologic changes that occur during treatment and systems for evaluating response to treatment and its effect on long-term survival. Methods: Pathological response to treatment was evaluated by the presence of residual neoplastic tissue, fibrosis, calcifications, necrosis, inflammatory infiltrates, foamy macrophages, foreign body-like giant cells, acellular pools of mucin and pleomorphic neoplastic nuclei. Results: 9 out of 10 women responded partially or well to neo-adjuvant chemoradiation therapy. In the patients that responded we can distinguish 3 groups with different morphological features. A first group showed little response with nearly no fibrosis or inflammation, resulting in expanded network of infiltrating small and angulated glands. The second group having an excellent response, was associated with expanded acellular pools of mucin with little remaining tumour glands. A third group showed a good response with an altered eosinophilic morphology of the remaining tumour nests. Conclusion: Identification of predictive markers associated with a good survival may prove clinically useful and implement an individualized treatment plan. E-PS-09-070 A unique presentation of blue nevus: a patient with endocervical location R. Yilmaz 1 , R. Bedir 2 , O. Semerci 2 1 Sanliurfa Siverek Community Hospital, Turkey, 2 Recep Tayyip Erdogan University Deparment of Pathology, Turkey Background & Objectives: Blue nevi, composed of spindle-like dendritic melanocytes, are benign lesions usually located on the reticular dermis of the skin and rarely located on mucous membranes. The endocervical blue nevus is a rare benign lesion which can be incidentally found in hysterectomy specimen. Since this is a very rare condition, we intended to report it in the literature. Methods: A 54-year-old female patient with a long history of menorrhagia was admitted to Obstetric and Gynaecology clinic. The patient had intramural leiomyoma in the radiologic examination. The patient underwent the surgical procedure of total abdominal hysterectomy. Results: We observed an endocervical polyp and a hyperpigmented area under this polyp on macroscopic examination. Histological examination revealed benign, pigmented, dendritic spindle cells between endocervical glands in the stroma of the uterus cervix. The dendritic spindle cells were immunoreactive for S100 and HMB45. The pigment showed a positive reaction to Fontana-Masson histochemical stain. Melanin pigment in the basal epithelium was not observed in the endocervix. There was no junctional activity in the endocervix. There were no increased typical-atypical mitotic activity, pleomorphism and necrosis. We reported this case as a blue nevus. Conclusion: Blue nevi of endocervix are usually found incidentally in hysterectomy specimens, and they are usually located in the stroma of the cervix. When located on the endocervix, the blue nevus might be confused with other benign or malignant lesions. Although the blue nevi seem to be lesions of low clinical significance, they require careful differential diagnosis with malignant melanoma, especially in scanty endocervical curettage or cervical biopsy specimens. Herein, we reported a case with endocervical blue nevus presented as an endocervical polyp, which is a rare phenomenon. E-PS-09-071 Epithelioid leiomyosarcoma with glandular-like pattern Y. Rogov 1 , N. Kornev 2 , A. Syantovich 2 , O. Solodkaya 2 , Y. Kuzmenka-Maskvina 1 , V. Zubovich 2 , E. Grigorieva 1 1 Belarusian Medical Academy of Postgraduate Education, Belarus, 2 City Clinical Pathology Bureau, Belarus Background & Objectives: Epithelioid leiomyosarcoma differs from ordinary spindle cell leiomyosarcoma by rounded or polygonal cells with eosinophilic or clear cytoplasm. They may be arranged in sheets, cords, trabeculae, nests. We report a case of recurrent leiomyosarcoma with unusual glandular-like pattern. Methods: A 71-year-old female patient was hospitalized with recently appeared abdominal pain. 8 years ago, she underwent combined treatment for uterine leiomyosarcoma. Clinical examination revealed tumour nodes in the greater omentum, mesentery of the small intestine and peritoneum measuring 4.0, 2.0 and 2.0 cm in diameter. They were removed, and tissue samples were investigated histologically and immunohistochemically. Results: Microscopic evaluation of all tumour nodes revealed an epithelioid leiomyosarcoma with areas of conventional type. Tumour cells were predominantly rounded, with eosinophilic cytoplasm. They focally formed glandular-like structures, lining the gaps in one or several rows. These sites looked like adenocarcinoma. Immunohistochemical staining was positive for SMA, Desmin, WT1 and negative for CK, GLUT1, BerEP4, Calretinin, ERG, CD31, CA125, CD117, DOG1, PAX8. Mitotic activity was high. Epithelioid leiomyosarcoma recurrence with glandular-like pattern was diagnosed. Conclusion: Epithelioid leiomyosarcoma occasionally can form pseudo-glandular structures that can be regarded as adenocarcinoma. Histological signs of myoid differentiation in tumour and immunohistochemistry help make the correct diagnosis. We could not find similar descriptions in the available literature. E-PS-09-072 Uterin mullerian adenosarcoma: an unusual tumour of the uterus S. Yacoub 1 , M. Sara 1 , D. Chiba 1 , N. Abdessayed 1 , B. Sriha 1 1 Department of Pathology Farhat Hached Hospital, Tunisia Background & Objectives: Uterine Mullerian adenosarcoma is an uncommon biphasic tumour composed of a malignant stromal component and benign epithelial component. It was originally described in 1974 and is considered of low malignant potential. We report 2 rare cases of Mullerian adenosarcoma. Methods: There were two women of 23 and 43 years old, presented clinically with vaginal bleeding. Clinical examination showed a polypoid mass projecting through the cervix. A polypectomy was performed in both cases Results: Macroscopic examination showed a fleshy and yellowish polypoid mass measuring 3,3 cm in the first case and 8,5cm in the second. No necrosis or hemorrhage were observed. The two tumours shared the same histological features, of a biphasic tumour, formed by a malignant stroma, with moderate to high density. Mesenchymal cells were elongated myofibroblastic-like with low to moderate atypia. Periglandular cuffing of the stromal cells around compressed or cystically dilated benigne endometrial glands, displaying focally progesterone impregnation. Immunohistochemistry was performed in only one case and showed Smooth muscle actin (SMA) expression by stromal cells and negativity of desmin and H-caldesmon. Conclusion: Adenosarcoma of uterus is a biphasic tumour of generally low malignant potential. A complete and Monobloc surgical resection is the ideal therapeutic option. E-PS-09-076 Sex cord-stromal tumours of the ovary: clinicopathological and genetic analysis C. Bartosch 1 , S. Alves 2 , M. Pinheiro 3 , M. Farinha 1 , F. Pereira 2 , J. Costa 1 , F. Silva 1 , R. Santos 3 , A. Peixoto 3 , S. Sousa 2 , A. Petiz 4 , M.R. Teixeira 3 , D. Pereira 2 1 Department of Pathology IPOP, Portugal, 2 Department of Oncology IPOP, Portugal, 3 Department of Genetics IPOP, Portugal, 4 Department of Gynaecology IPOP, Portugal Background & Objectives: Sex cord-stromal tumours are a heterogeneous group of rare neoplasias, with variable biological behavior. This study aims to describe the clinico-patological features of a series of patients with pure sex cord tumours and mix sex cord-stromal tumours of the ovary. Methods: Retrospective cohort study of a series of patients with sex cord-stromal tumours of the ovary, managed at Portuguese Oncology Institute of Porto (1994-2018). We collected clinical data, reviewed histological material and performed FOXL2 gene mutations analysis. Results: Initially we included 41 patients, but only 34 had available histological material. After histological review, tumour subtype changed in 6 patients and one was excluded. We included in the analysis 33 patients, with a median age at diagnosis of 53 (4-79) years. Histological subtypes included 18 adult granulosa cell tumours (TCGA), 9 Sertoli-Leydig cell tumours (TCSL), 2 Sertoli cell tumours and other (n=4). We identified FOXL2 gene mutations in 14/29 patients, of which 13/16 (81%) corresponded to TCGA, and 1 TCSL. The majority (87.9%) was diagnosed as FIGO stage I. Ten patients had recurrences and 6 died of the disease. Conclusion: Our series clinico-pathological features are in accordance with previous studies, emphasizing the variability in clinical presentation and morphology of these tumours. The frequency of FOXL2 gene mutations is also concordant with that reported in the literature. This study highlights the need for central review and reinforces the diagnostic utility of FOXL2 gene mutations. E-PS-09-077 A review of the morphologic features of endometrial hyperplasia without atypia, complex after progesterone therapy S. Noh 1 , E. Shin 2 , J. Kim 2 , J.Y. Shim 2 1 CHA Gangnam Medical Center, CHA University School of Medicine, Republic of Korea, 2 CHA University School of Medicine, Republic of Korea Background & Objectives: Endometrial hyperplasia without atypia is a precursor of endometrial carcinoma. Well differentiated endometrial carcinoma occurs in 1-3% of women with hyperplasia without atypia. Because of retaining fertility, women with endometrial hyperplasia or early stage endometrial carcinoma want to manage with conservative Progesterone therapy. However, Progesterone therapy changes the endometrial morphology and gives pathologist difficulties. To help determine the therapeutic effect, we aimed to review and list common morphologic features that can distinguish residual complex endometrial hyperplasia without atypia from Progesterone effect. Because the degreee of nuclear atypia is difficult to make intuitive judgment, we reviewed the complex hyperplasia without atypia with the greatest morphological diversity. Methods: Endometrial curettage and/or biopsy samples that were diagnosed with complex hyperplasia without atypia and had three or more follow-up curettage and/or biopsy of the uterine endometrium from 2008 to present were searched from the database of the Department of Pathology, CHA Gangnam Medical Center. Fifty-two cases diagnosed with complex hyperplasia without atypia were retrieved, but 12 cases were excluded because material insufficiency due to either therapeutic effect or sampling error. Thus, 40 cases were finally included in the review. Results: Of the retrieved 40 cases, the most frequent morphologic features of complex hyperplasia without atypia after Progesterone treatment were papillary configuration in all cases. All cases turned into dull and blunt shape on follow-up. The helpful features were residual or new squamous morule. The reasons for misclassification of nuclear atypia were eosinophilic metaplasia, after hormonal therapy, similar to apocrine metaplasia in the breast. Two cases of mucinous metaplasia, similar to endocervical glands of uterine cervix can be misdiagnosed as carcinoma, because of their architectural complexity. Conclusion: Although advances in medical technology have increased the number of people receiving Progesterone treatment, there are still rare reports of changes in morphology after Progesterone therapy. However, false-positives or false-negative cannot be avoided to some extent. Identifying papillary configuration and squamous morule has a merit in itself in that it often leads to the identification of underlying complex hyperplasia without atypia. E-PS-09-078 A morphometric study of hypoxic and vascular changes of chorionic villi in maternal vascular malperfusion D. Obradovic 1 , R. Jankovic 1 , J. Jevtic 1 , D. Opric 1 1 Faculty of Medicine, University of Belgrade, Serbia Background & Objectives: Maternal vascular malperfusion (MVM) represents altered uterine and intervilous blood flow resulting in recognizable hystological pattern of placental hypoxic injury with potential adverse effect on fetus. MVM is frequently found in pregnancies complicated by preeclampsia and intrauterine growth restriction. Being that MVM is vascular and hypoxic phenomenon affecting fetoplacental exchange we analysed a level of vascularisation of chorionic villi and level of intravillous fibrosis. Methods: Five placentas with MVM were morphometricaly analysed. Inclusion parameters were syntitial knots present in 30% or more terminal villi, retroplacentar haematoma and weight of placenta under 10 th percentile for week of gestation. Materials were obtained from autopsy speciments at Institute of Pathology, Medical Faculty in Belgrade. Formalin fixed paraffin embedded tissues were stained with Masson-Trichrome stain for evaluation of fibrosis and blood vessels were marked with CD34 antibody. All images were analysed using Fiji software. Statistical analysis was performed using Microsoft Excel software. Results: Results of statistical analysis have shown trend of correlation between higher level of vascularisation of chorionic villi with increase of deposition of intravillous fibrin. Analysis haven’t shown statistical significance which may be expected due to small sample. Conclusion: We believe these observations should shed some light on the way of thinking about fibrosis of chorionic villi. We are of opinion that perhaps deposition of intravillous fibrin shouldn't be observed as strictly degenerative, but instead as positive reactive change as part of adaptation to hypoxia in placenta. E-PS-09-079 Aggressive angiomyxoma of the uterus: a case report Y. Rogov 1 , N. Kornev 2 , Y. Kuzmenko-Moskvina 1 , A. Syantovich 2 , S. Budanova 2 1 Belarusian Medical Academy of Postgraduate Education, Belarus, 2 City Clinical Pathology Bureau, Belarus Background & Objectives: Aggressive angiomyxoma is a rare myxoid mesenchymal tumour of the pelvis and perineum, which is not included in the latest WHO Classification of tumours of the uterine corpus since it was found in this location in exceptional cases. Morphological diagnosis may be difficult, since the tumour is similar to various myxoid sarcomas. We report our observation of this neoplasm. Methods: A 58-year-old woman was hospitalized with complains of acute minor vaginal bleeding for some days. The patient was in menopause for 10 years. The examination revealed a submucous node in the body of the uterus 5,5 cm in diameter. Structures suspected of sarcoma were found in curettage tissue samples. After radical hysterectomy, a macroscopic, histological and immunohistochemical study of this tumour was performed. Results: The tumour had a soft gelatinous appearance with small hemorrhages on cut sections and predominantly well-defined margins, unencapsulated. Microscopically it was highly myxoid, composed of uniform, small, stellate and spindle shaped cells with indistinct borders, without pleomorphism, necrosis and significant mitotic activity. Cellularity was low to moderate. Vessels of various sizes were regularly present, some of them with thick muscular walls. Immunohistochemical staining was positive for Desmin, Vimentin, ER, PR, weakly positive for CD34 and negative for MyoD1, S100, SMA. Ki67 reached about 5-10% (up to 20% in “hot spots”). An aggressive angiomyxoma was diagnosed. Conclusion: Aggressive angiomyxoma can sometimes be found in the body of the uterus. The diagnosis of this tumour in the study of curettage biopsies is difficult. It should be considered in the differential diagnosis of uterine myxoid lesions. Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-10 | Haematopathology Sunday, 8 September 2019 – Wednesday, 11 September 2019 E-PS-10 | Haematopathology E-PS-10-001 Angioimmunoblastic T-cell lymphoma in patient with plasm cell myeloma. Case report and review of the literature A. Abuomar 1 , T. Lopez 1 1 Hospital General Universitario de Elda, Alicante, Spain Background & Objectives: Angioimmunoblastic T-cell lymphoma (AITL), a subtype of mature peripheral T cell lymphoma, is a neoplasm of mature T folicular helper characterised by a systemic disease involving lymph nodes (LN). AITL has a typical morphological, immunohistochimical (IHQ) and molecular signature. Usually affects older people with a poor prognosis. Rarely associates with B cell neoplasm, exceptionally with plasm cell myeloma (PCM) with few cases reported in the literature to the best of our knowledge. Methods: A 72 years old man with PCM with high risk cytogenetics, on treatment, and chronic renal faillure was admitted to our hospital with persisted fever, skin rush, generalized lymphadenopathy and positive polymerase chain reaction (PCR) and immunoglobulin M for Epstein-Barr virus (EBV). No improvement was seen after a few weeks of symptomatic treatment. Lymphadenectomy of an enlarged axillary lymph node was done rule out a possible lymphoproliferative disorder. Results: LN with total effacement of morphology, prominent vascularity with arborization of high endothelial venuls (HEV), a proliferation of small to medium size atypical lymphocytes with clear cytoplasm and distinct cell membrane in an inflammatory back ground. No cells of Hodgkin or Reed–Sternberg morphology were seen. IHQ: CD3, CD4, BCL6, CD10, ICO, PD1 and CXCL13. Few cells expressed CD20+, CD30+. EBER1+ cells were seen. CD23 revealed a marked folicular dentritic cell proliferation entrapping HEV. TCR gene rearrangement were clonal. Conclusion: Typical morphological, IHQ and molecular characteristics of AITL are diagnostic in the majority of cases, however, realizing a differential diagnosis with Reactive T Zone Hyperplasia, Angiofollicular Lymphoid Hyperplasia (Castleman Disease), Plasma Cell Type, Peripheral T Cells Lymphoma NOS, T-cell/histiocyte-rich B-cell Lymphoma and Hodgkin Lymphoma is mandatory. It is recommended to report percent of CD30+ cells since target therapy is available. E-PS-10-002 Retroperitoneal and kidney infiltration with anaplastic plasm cell myeloma simulating an obstructive acute renal failure. Case report and literature review A. Abuomar 1 1 Hospital General Universitario de Elda, Alicante, Spain Background & Objectives: Anaplastic plasm cell myeloma (APCM) is a rare, highly aggressive and treatment-resistant subtype of plasm cell myeloma (PCM) with Identical morphological and Immunohistochemical (IHQ) findings to plasmoblastic lymphoma (PL). We report, up to our knowledge, the second case in literature with clinical presentation of an obstructive acute renal failure duo to retroperitoneal and renal infiltration. Methods: A 67 years old immunocompromised heart transplant man was admitted to nephrology department with a clinical picture of obstructive acute renal failure. CT scan suggested metastatic urethral carcinoma showing multiple retroperitoenal nodular masses with infiltration of left kidney and ureter, dilatation of renal chalices, enlarged retroperitoneal and hiliary adenopathy. Bone marrow aspiration showed sheets of anaplastic plasma cells. Monoclonal serum and urine immunoglobulins were detected. A total nephrectomy was performed as a suspicious of metastatic urtetral neoplasm persisted. Results: Gross examination showed a multiple perirrenal nodular masses of 1-5cm which extrinsically infiltrated left renal parenquima and proximal ureter simulating intraurethral neoplasm with stenosis.Microscopic study showed a monomorphic diffuse proliferation of large cells with plasmoblastic appearance,multinucleated plasmoblast,multiple mitosis and numerous apoptotic figures were seen, with a starry sky appearance.Small cells with plasmocytoide appearance were seen.IHQ:CD138+,CD79A+,CD56+,MUM1+,CD20-,CD10-, LMP1-,PAX5-,CD45-,ALK-,HHV8-, EBER1+Bone marrow monoclonal aberrant plasm cells with 1q21 amplification and 14q32 IGH rearrangement confirmed the diagnosis of APCM. Patient died duo to gastric cancer. Conclusion: In the setting of immunodeficiency, APCM and PL can be associated with EBV, thus making differencial diagnosis always challenging and sometimes impossible. The diagnosis of APCM should base on clinico-morphological, IHQ and molecular findings. Serum/urine monoclonal immunoglobulins is vital for the diagnosis, though patients with PCM can develop lymphproliferative disorders including PL. E-PS-10-003 Cytokeratin expression in acute leukaemia: a potential pitfall J. Garry 1 , E. O'Driscoll 1 , R. Werner 1 , A. Connolly 1 , B. Hayes 1 1 Cork University Hospital, Ireland Background & Objectives: Cytokeratin expression is characteristic of carcinomas but is thought rare in haematological malignancies. While several studies have examined cytokeratins in mature lymphoid neoplasms, and several case reports describe cytokeratin expression in acute myeloid leukaemia (AML), no systematic assessment has to our knowledge been previously reported in AML or in acute lymphoblastic leukaemia (ALL). We aimed to assess expression of cytokeratins by immunohistochemistry in a series of bone marrow trephine biopsies from patients with acute leukaemia. Methods: Fifty bone marrow biopsy specimens from 2013-2017, SNOMED coded as “acute leukaemia” were selected from our files. Original H&E slides were retrieved, new sections stained with MNF116 and AE1/3, and all slides reviewed by a consultant and a trainee pathologist. Cytokeratin expression in tumour cells was graded semiquantitatively from 0 to 3+. The number of cells staining was recorded as 1-10%, 10-25%, 25-50%, 50-75% or 75-100%. Cases with at least 2+ positivity were further examined with an extended cytokeratin panel. Results: 41 AML and 9 ALL cases were included. The reproducibility of 1+ staining was very poor (AE1/3 κ = 0.16, MNF116 κ = 0.13) and so only 2+/3+ staining was considered positive. Three of the AML cases (7.3%) showed at least 2+ staining with AE1/3 or MNF116, which was cytoplasmic and dot-like in character, involving at least 10% of the tumour cells. One case showed 3+ MNF116 positivity in 50-75% of tumour cells and also had 3+ staining with CAM5.2. Conclusion: Cytokeratin expression in acute leukaemia is uncommon, but not rare (7.3% of all AML cases in this retrospective study), and can be strong and diffuse. Leukaemia can present at extramedullary sites, where cytokeratins may be included in a broad immunohistochemical panel for work-up of a poorly differentiated malignant neoplasm. Pathologists should be aware of the potential pitfall in this scenario. E-PS-10-004 Histomorphologic evaluation of bone marrow involvement in mantle cell lymphoma and its correlation with flowcytometric immunophenotyping S. Sharma 1 , S. Yadav 1 , K. Rahman 2 , M. Murari 1 1 Department of Pathology, SGPGIMS, Lucknow, India, 2 Department of Clinical Haematology, SGPGIMS, Lucknow, India Background & Objectives: Mantle cell lymphoma (MCL), accounts for approximately 3-10% of Non-Hodgkin lymphomas. It is usually composed of monomorphic small to medium-sized lymphoid cells and needs to be distinguished from other small B - cell lymphoproliferative diseases i.e. CLL, B - PLL, follicular lymphoma and marginal zone lymphomas. The aim of the study was to analyse the prevalence of bone marrow involvement and correlate histomorphologic findings with flow cytometric analysis in a series of patients with MCL. Methods: We retrospectively analysed 26 consecutive patients of MCL diagnosed over a period of 3 years for bone marrow (BM) involvement. BM involvement was assessed by conventional morphology, IHC and flow cytometry (FC) in BM aspirate and trephine biopsy specimens. Results: MCL comprised 13.7% of all Non-Hodgkin’s lymphomas with BM involvement. BM involvement was identified in 22 trephine biopsies. The extent of lymphomatous infiltration ranged from 10-90%. Diffuse pattern of infiltration was seen in 10 cases. All cases were positive for CD5, CD20, and negative for CD23 on both FC and IHC. Cyclin D1 was positive in all cases on IHC. There was a significant correlation between percentage marrow infiltration on BM histology and FC (Spearman’s correlation coefficient 0.67, p-value 0.014). Conclusion: Bone marrow involvement was found in majority of patients with MCL. Bone marrow involvement was associated with high circulating lymphocyte count and serum LDH levels. The histomorphologic findings in BM trephine correlated with flow cytometric analysis. E-PS-10-005 Lollipops and onions: Castleman disease-like changes in malignant lymphoma - comparison with true Castleman disease and IgG4-related lymphadenopathy M. Válková 1 , K. Kamaradua 1 1 The Fingerland Department of Pathology, Charles University Faculty of Medicine and University Hospital in Hradec Kralove, Czech Republic Background & Objectives: Morphological features of hyaline vascular type of Castleman disease include atrophic germinal centers, prominent mantles with onion skinning and increased vascularity with penetration of vessels into germinal centers (lollipops). Similar patterns can be seen in a subset of IgG4-related lymphadenopathy and in rare cases of malignant lymphoma causing a possible diagnostic pitfall. Methods: Eleven cases were retrieved from the archive using keyword search for lymph nodes with Castleman disease-like features. All cases have been reviewed with focus on distinguishing malignant and benign lesions. Additional testing was performed in all cases including basic immunohistochemical panel (CD20, CD23, bcl-2, CD5, cyclin D1, Ki67, CD10, bcl-6, immunoglobulin light chains and IgG4). Results: Out of eleven cases, five cases presenting with partial or fully developed Castleman disease-like features were lymphomas including three cases of follicular lymphoma and two cases of mantle cell lymphoma. Immunohistochemistry was crucial for establishment of diagnosis of malignant lymphoma. Four cases fulfilled morphological criteria of probable IgG4-related lymphadenopathy with high numbers of IgG4+ plasma cells. Two cases with prominent fully developed changes were classified as idiopathic multicentric Castleman disease after thorough clinical investigation. Conclusion: Presence of Castleman disease-like features is not always diagnostic just of Castleman disease. In our series, they were observed more frequently in other disorders, namely malignant lymphoma (where only part of the lymph node is usually involved) or IgG4-related lymphadenopathy. Awareness of these changes is crucial and combination with immunohistochemistry and molecular studies can help to avoid a possible misdiagnosis. The work was supported from Fund-Project BBMRI-CZ, No: EF16 013/0001674. Supported by the programme PROGRES Q40/11. Supported by the project BBMRI-CZ LM20150. E-PS-10-006 An unusual case of BCL-2, BCL-6, CD10 & MUM-1 quadruple negative follicular lymphoma S. Shawash 1 , N. Abdullah 1 1 King Hussain Cancer Center, Jordan Background & Objectives: Nodal follicular lymphoma originates in germinal centers as proven by markers such as CD10 and BCL-6. It is renowned for BCL-2 overexpression which results from translocation t (14; 18)/IGH-BCL2. Rarely, especially in high grade cases, one or more immunomarkers might be lost, making accurate diagnosis difficult. We present an unusual case of follicular lymphoma showing loss of BCL-2, CD10, BCL-6 and negative MUM-1. Methods: Our patient is a 66-year-old female with resected colonic adenocarcinoma (pT3N2b). Serial CT scans showed progressively enlarging lymph nodes despite adjuvant chemotherapy. Excisional biopsy was obtained and revealed multiple lymph nodes, some showing effaced architecture, replaced by large follicles which are composed predominantly of centroblasts with centrocytes. Extracapsular extension was also seen. Three lymph nodes showed extensive necrosis mostly due to previous intervention. Immunohistochemical stains showed tumour cells were positive for CD20 and PAX-5. Results: However, BCL-2, CD10, BCL-6, CD30, CD15, CD3 and MUM-1 were all negative. CD23 highlighted attenuated dendritic meshwork. Ki67 was up to 40% and highlighted loss of zonation. Flow cytometry failed to show neoplastic process. FISH using dual fusion probe for IGH/BCL-2 gene rearrangement was negative. Finally, PCR showed clonal immunoglobulin heavy chain and kappa light chain gene rearrangement. As a result, a diagnosis of follicular lymphoma grade 3a was made. Bone marrow biopsy revealed minimal para-trabecular involvement. Conclusion: In conclusion, unusual loss of expression in follicular lymphoma should not preclude accurate diagnosis. Such cases remind us that the histomorphology is our cornerstone to make a diagnosis. E-PS-10-007 Erdheim-Chester disease co-occurring with cholelithiasis associated Langerhans cell histiocytosis S. Aviel-Ronen 1 , S. Fichman-Horn 2 , S. Zoabi 3 , R.D. Mazor 4 , G. Gitstein 5 1 Department of Pathology, Sheba Medical Center, Tel-Hashomer, Israel, 2 Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel, 3 Surgery Department, Holy Family Hospital, Nazareth, Israel, 4 Institute of Haematology, Assuta Medical Center, Tel Aviv, Israel, 5 Pathology Department, Sourasky Medical Center, Tel Aviv, Israel Background & Objectives: Histiocytoses are rare heterogeneous mononuclear phagocytes derived neoplasms. Two of the more recognized hystiocytoses are Langerhans cell histiocytosis (LCH) and Erdheim-Chester disease (ECD). Both entities often harbor the BRAF V600E mutation, which may be the link between them. The coexistence of LCH with ECD is infrequent and is referred to as mixed LCH/ECD. Here we describe an unusual case of ECD patient who developed cholelithiasis associated with LCH infiltrate in the gallbladder. Methods: The medical records, imaging tests and pathological findings of a 34 years old patient have been studied and are presented. The patient went through cholecystectomy due to cholelithiasis. Three years before he was diagnosed with ECD based on characteristic clinical-radiological-pathological features. His presentation included multifocal disease involvement of the hypophysis with central diabetes insipidus, lower appendicular skeleton inducing pain and mesenteric fat infiltrates causing abdominal ache. Imaging revealed the typical "hairy kidney" and bone biopsy supported the diagnosis as well. Results: The resected gallbladder showed distorted structure with thickened wall and cholelithiasis. Microscopic examination identified prominent mucosal infiltrate of histiocytes having irregular nuclei with occasional grooves, accompanied by numerous eosinophils. On immunostains the histiocytes showed positive staining for CD68, CD1a, S100 and langerin. Overall, the morphological features and immunostain results were consistent with LCH. In contrast, the left tibia biopsy preformed 3 years before showed infiltrate of CD68 positive, CD1a negative and S100 negative histiocytes that supported the diagnosis of ECD. Conclusion: Altogether features reflect co-occurrence of ECD and LCH, otherwise named mixed LCH/ECD. Not only this is a rare condition, its presentation in association with cholelithiasis has not been described yet. E-PS-10-008 Follicular dendritic cells sarcoma - two case reports S. Sotiriou 1 , A. Bouzakis 2 , I. Kostopoulos 1 , V. Tzioufa 1 , T. Koletsa 3 1 Pathology Department, Faculty of Medicine, Aristotle University of Thessaloniki, Greece, 2 Histopathology Lab. Serres P, Greece, 3 Pathology Department, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece Background & Objectives: Follicular dendritic cell sarcomas (FDCSs) are rare neoplasms. The aim of these case reports is to raise awareness regarding this unusual entity and to point the importance of the differential diagnosis. Methods: A 46-year-old man and a 38-year-old woman presented with right and left cervical lymphadenopathy respectively. The clinical history and examination were otherwise unremarkable. Both have undergone a diagnostic lymphadenectomy. Results: Microscopically, the lymph nodes were almost entirely replaced from a neoplastic population of ovoid to spindle cells with moderate atypia. The nuclei were elongated or ovoid, occasionally exhibiting clear changes or membrane folding. Giant cells with pleomorphic nuclei with pseudoinclusions were observed in the second case. The neoplastic cells of both lesions showed similar immunophenotype: Vimentin+, CD21+, CD23+, Fascin+, HLA-DR+, S100+/-, CD68+/-, CD45-, AE1/AE3-, MelanA-, HMB45-. Based on the histological and immunohistochemical findings, our final diagnosis was that of FDCSs. Conclusion: Depending on the location, FDCSs should be differentiated from other histological subtypes of dendritic cell tumours, but also from primary or metastatic neoplasms. If FDCS is not considered in the differential diagnosis, its positivity to nonspecific markers, such as CD68 and S100 protein can lead to misdiagnosis. Clinicopathological correlation and immunohistochemical assays are of paramount importance in the differential diagnosis.