{"paper_id":"1572a3f3-a3b4-4b0e-97c4-a848f1665665","body_text":"C A S E R E P O R T Open Access\nPrimary extragenital endometrial stromal\nsarcoma of the lung: first reported case and\nreview of literature\nLara Alessandrini 1*, Francesco Sopracordevole 2, Giulio Bertola 3, Simona Scalone 4, Martina Urbani 5,\nGianmaria Miolo 4, Tiziana Perin 1, Fabrizio Italia 6 and Vincenzo Canzonieri 1\nAbstract\nBackground: Endometrial stromal sarcomas arising in extrauterine and extraovarian sites, in the absence of a primary\nuterine lesion are quite rare, especially in the absence of endometriosis. They usually present as an abdominal or pelvic\nmass lesion.\nCase presentation: In 2007, a 45-year-old woman underwent total hysterectomy for in situ squamous cell carcinoma of\nthe cervix. In 2014, an upper left pulmonary lobectomy was performed for a mass, which was provisionally diagnosed as\nprimary carcinosarcoma of the lung. A second histological revision of the lung surgical specimen was performed in the\nPathology Unit of our Institute. After extensive immunohistochemical analyses, the preferred diagnosis was spindle-cell\nsarcoma, consistent with high-grade extragenital endometrial stromal sarcoma (EESS). A review of all slides of the\nhysterectomy specimen confirms the original diagnosis: no evidence of stromal tumor was found. Afterwards, the patient\ndeveloped multiple and metachronous pulmonary lesions and a scapular soft tissue mass, which showed the same\nmorphophenotypic features of the first lung mass. The patient was treated with antiblastic therapy, surgical resection and\nradioablation, when appropriate. To date, the patient has no signs or symptoms.\nConclusions:The authors present the first case of primary EESS arising in the lung with no association with endometriosis\npublished to date. Detailed clinical history and follow-up are also described. Moreover, extensive literature review is\nreported, along with differential diagnoses, immunohistochemical and molecular findings, pathogenetic hypotheses\nand treatment options. The knowledge of EESS potential extrauterine location and of its peculiar morphophenotypic\naspects are required for a correct diagnosis, and for choosing the most suitable treatment.\nKeywords: Extragenital endometrial stromal sarcoma, Lung, Immunohistochemistry, Case report\nBackground\nEndometrial stromal sarcoma (ESS) is an uncommon\nmesenchymal tumor of the uterus, which accounts for\nless than 1% of all uterine malignancies but it is the\nsecond most common uterine malignant mesenchymal\ntumor [1]. The latest World Health Organization Classi-\nfication [1], categorizes ESS into low-grade ESS (LGESS),\nhigh-grade ESS (HGESS) and undifferentiated endomet-\nrial sarcoma (UES). LGESS are typically composed of\ncytologically bland fusiform cells resembling stromal\ncells of proliferative-phase endometrium, intermingled\nwith numerous small plexiform arterioles, permeating\nthe myometrium as well as the intramyometrial or para-\nmetrial vessels. The mitotic rate is usually lower than 5\nmitoses/10HPF. They show an indolent course: recur-\nrences and metastases are rare and occur after long\nperiods of time [1, 2]. In contrast, both HGESS and UES\nhave a malignant behavior. They often exhibits myome-\ntrial invasion, hemorrhage and necrosis, as well as\nmarked nuclear pleomorphism with round cell morph-\nology (and a minor component part of low-grade spindle\ncell morphology) and high mitotic activity with 10\nmitoses/10HPF or higher. Patients are more likely to\ndevelop recurrences and die from disease. The most im-\nportant morphologic feature that distinguishes ESS from\n* Correspondence: lara.alessandrini@cro.it\n1Pathology, IRCCS-National Cancer Institute, Via F. Gallini 2, 33081 Aviano, Italy\nFull list of author information is available at the end of the article\n© The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0\nInternational License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and\nreproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to\nthe Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver\n(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.\nAlessandrini et al. Diagnostic Pathology  (2017) 12:36 \nDOI 10.1186/s13000-017-0627-2\n\nUES is that the latter lacks overt resemblance to proliferative\nendometrial stroma.\nEndometrial stromal sarcomas arising as primary\ntumors in extrauterine and extraovarian (i.e., extragenital\nendometrial stromal sarcomas) sites are quite rare, and\nreported in the English medical literature as small series\nor case reports (Table 1) [3 – 29].\nThe clinical-pathological features of primary EESS\nhave not been widely investigated yet. To the authors ’\nknowledge, this is the first case reported of EESS arising\nin the upper left lobe of the lung in a 45-year-old woman\nwithout associated endometriosis and in the absence of\na primary genital ESS. An extensive review of literature\nis also reported, along with differential diagnoses, immu-\nnohistochemical and molecular findings, pathogenetic\nhypotheses and treatment options.\nCase presentation\nClinical history\nIn 2007, a 38-year-old female was hospitalized for an\nulcerated uterine cervical lesion which, after cervical bi-\nopsies, showed an in situ squamous cell carcinoma.\nSubsequently, an abdominal CT scan revealed an en-\nlarged, dishomogeneous uterus, with hypodense mass of\n5 cm adjacent to the posterior wall of the bladder. Two\nmonths later, the patient underwent total abdominal\nhysterectomy with bilateral salpingectomy and pelvic\nlymphadenectomy. In the intraoperative phase, the\nuterus was found to be mobile and ovaries were normal.\nNeither enlarged lymph nodes nor peritoneal lesions or\nascites were noted.\nOn histological examination of the surgical specimen,\na well-differentiated squamous cell carcinoma in situ of\nthe cervix, measuring 4 mm in maximum diameter, with\nbasaloid morphology, was identified. Three additional\nleiomyomata of the uterine corpus, besides the larger\none already identified on CT scan, were also microscop-\nically found.\nIn 2014, the patient presented to medical observation\nwith a pulmonary mass (Fig. 1). Upper left lobectomy\nwas performed. The final pathologic diagnosis was carci-\nnosarcoma of the lung.\nA second histological revision of the lung surgical\nspecimen was performed in March 2014 in the Pathology\nUnit of our Institute. The preferred diagnosis, after\nextensive immunohistochemical analyses, was spindle-cell\nsarcoma, consistent with high grade EESS.\nPost-operative staging with thoracic, abdominal and\npelvic CT scan did no have any abnormal findings and a\nfollow-up was proposed. After five months, a CT scan\nwas performed: it revealed a left pulmonary lesion with a\nmaximum diameter of 18 mm. Chemotherapy treatment\nwith carboplatin AUC 5 and paclitaxel 175 mg/mq every\nthree weeks was started. After three courses of antiblastic\ntherapy, the lesion in the left lung appeared to be in-\ncreased in volume (27 mm of diameter) on CT scan. After\nmultidisciplinary discussion, a surgical intervention (atyp-\nical segmentectomy of lower lobe of the left lung) was\nperformed.\nAlmost three months after surgical intervention, a new\npulmonary lesion located in the right lung was detected\nby CT scan. The lesion was subsequently treated with\nradiofrequency ablation. As a consequence of the\nprocedure, right pleural effusion after 24 h and after five\ndays by the appearance of right pneumothorax after five\ndays appeared. Shortly after tube insertion, additional\nradiographs were taken: they showeda rapid decrease in\nthe size of the pneumothorax. The thoracic drainage was\nremoved and patient was discharged from the hospital.\nAfter one month, a CT scan was repeated. The scan\nshowed surgical and radiofrequency ablation effects and\na new pulmonary lesion of uncertain nature, measuring\n4– 5 mm of maximum diameter. Hormonal therapy with\nprogestin (acetate medroxyprogesterone 1 gr daily) was\nprescribed.\nNo radiological signs of progression were noted until\nDecember 2015, when new lung lesions located in the\nlower lobe of the right lung and upper lobe of the left\nlung were detected on CT scan.\nIn January 2016, the patient referred the appearance of\na soft tissue mass, rapidly enlarging, located in the left\nperiscapular region. A tru-cut biopsy of the soft tissue\nlesion was performed: histological examination revealed\na neoplastic lesion with spindlecell morphology, reminiscent\nof the upper left lobe EESS.\nA second line polychemotherapy with epirubicin and\nifosfamide was started. After three courses of chemo-\ntherapy, radiological evaluation through CT scan re-\nvealed a decrease of the diameter of the right lung lesion\nand the disappearance of the lesion in the left lung. At\nthe follow-up visit, the patient was in good conditions\nwell, with no clinical signs or symptoms of the disease\nand no pathological findings on CT scan; routine laboratory\ntests were normal.\nSigned written consent was obtained from the patient\nfor this case report.\nMethods\nTwo and half-micron sections from formalin-fixed paraf-\nfin embedded tissue of the resected lobe and of the hys-\nterectomy specimen were cut and immunohistochemical\nanalysis was performed through an automated system\n(Benchmark-XT, Ventana, Tucson, AZ, US). The following\nprimary antibodies were used:\nCD117 (pathway c-kit, clone 9.7, pre-diluted; Ventana,\nTucson, AZ, US), Estrogen receptor (monoclonal anti-\nbody, clone SP1, prediluted, Ventana), Progesteron\nreceptor (monoclonal antibody, clone 1E2, prediluted,\nAlessandrini et al. Diagnostic Pathology  (2017) 12:36 Page 2 of 9\n\nTable 1 Clinical characteristics of EESS cases presented in Literature\nRef Site N° of cases Age (Range) N° of cases with\nhistory of\nendometriosis\nN° of cases with\nhistory of\ngynecologic surgery\nN° of cases with\nconcurrent\nendometriosis\nTreatment (N° of pts) Follow-up: time (range)\nand outcome (N° of pts)\n3,6,17, 21,26 Pelvis 6 34 –50 2 1 4 resection + radioTX (1)\nresection (3)\nNA (2)\n10 mo-1y; DOD (1), NED\n(2), NA(3)\n6,13, 15, 17,18 Omentum, abdomen,\nretro-peritoneum, mesentery\n54 6 –71 1 1 3 resection + radioTX (1)\nresection (4)\n11 mo-4y; NED (3), NA(1);\nrecurrence (1)\n5,10,11, 12,14,\n19,20, 21,23, 27,\n28\nSmall bowel, colon, rectum 11 38 –80 3 5 6 resection + radioTX (1)\nresection + chemoTX (3)\nresection (6)\nNA (1)\n4 mo-4y; DOD (1), NED (6),\nNA(2); recurrence (2)\n22 omentum, mesentery, colon,\nliver, bladder, abdominal nodes,\npelvis, vagina, aryepiglottic fold\n38 cases EESS;\nage:27–81 (range)\nNA NA 14/38 cases resection + chemoTX\n+/− radioTX\nNED (12/38 cases, range :\n15–174 mo)\nDOD (8/38 cases; range\n36–336 mo); AWD (13/38\ncases; range:6-145mo)\n25 stomach 37 –54 NA 1 none resection NA\n13 Liver 1 31 1 1 1 resection NED; 4 y\n4,8,9, 16,17, 24 vagina 6 32 –45 none 1 none resection + radioTX (2)\nresection + chemoTX (1)\nresection (3)\n18 mo-38 mo; NED (5),\nNA (1)\n7,29 vulva 2 34 –50 none 2 1 Resection (2) 28 mo-6 y NED (2)\nTX therapy, NED no evidence of disease, DOD dead of disease, NA not available, mo months, y year/s, AWED alive with disease\nAlessandrini et al. Diagnostic Pathology  (2017) 12:36 Page 3 of 9\n\nVentana), Ki67 (monoclonal antibody, clone 30.9, predi-\nluted, Ventana), CD10 (monoclonal antibody, clone\nSp67, prediluted, Ventana), CD34 (monoclonal antibody,\nclone QBEND/10; 1:400 dilution; Neomarkers, Free-\nmont, CA, USA), CD31 (monoclonal antibody, clone\nJC70, Prediluted, Cell Marque, Rocklin, CA, US),\nPankeratin (CkAE1/AE3/pCk26, pre-diluted, Ventana),\nMNF116 (monoclonal antibody, clone MNF116, predi-\nluted, Diagnostic Biosystem, Pleasanton, CA, US),\nsmooth muscle actin (SMA) (monoclonal antibody,\nclone 1A4, 1:100 dilution; DAKO, Glostrup, Denmark/\nCarpinteria, CA, US), H-Caldesmon (monoclonal anti-\nbody, clone E89, prediluted, Ventana), S100 (polyclonal\nantibody, 1:400 dilution; DAKO), MDM2 (monoclonal\nantibody, clone IF2, 1:100 dilution, Calbiochem, Merk,\nDarmstardt, Germany), D2-40 (monoclonal antibody,\nclone podoplanin, prediluted, Cell Marque), CD99\n(monoclonal antibody, clone o13, prediluted, Ventana),\nMyogenin (monoclonal antibody, clone FD5, 1:50\ndilution, Cell Marque), Myoglobin (polyclonal, predi-\nluted, Ventana), Vimentin (monoclonal antibody, clone\nV9, prediluted, Ventana), Desmin (monoclonal antibody,\nclone De-R-11, prediluted, Ventana), TTF1 (monoclonal\nantibody, clone 8G9G3/1, prediluted, Ventana).\nThe color was developed with 3.3 ′-diaminobenzidine\n(DAB), and the slides were counterstained with Meyer ’ s\nhematoxylin. Appropriate positive and negative controls\nwere run concurrently.\nMorphological findings\nThe histological examination of hematoxylin and eosin\nstained slides of the pulmonary lesion showed uniform\nspindle cells organized in a diffuse pattern (Fig. 2a, b, c),\nwith mild atypia and foci of necrosis (Fig. 2d), in a back-\nground of fibromyxoid stroma (Fig. 2d). The tumor cells\nhad oval to round nuclei with inconspicuous nucleoli,\nand eosinophilic cytoplasms. Some small-sized thick-\nwalled vessels were unevenly distributed among the\nstroma (Fig. 2a, d). Mitotic rate was high, ranging up to\n20 mitoses per 10 high-power fields. Alveolar epithelium\nwas focally entrapped by the neoplastic cells (Fig. 2a, c).\nDespite a thorough examination, endometriotic spots\nwere not identified in the tumor or in adjacent non-\nneoplastic tissue.\nA review of all slides from the hysterectomy specimen,\nwhich included the large lesion identified on CT scan\nplus three additional microscopically found leiomyomas,\nconfirmed the original diagnosis of squamous carcinoma\nin situ of the cervix with leiomyomas of the uterine wall.\nNo evidence of ESS or endometrial stromal nodules\nwas found.\nImmunophenotipic findings\nOn immunohistochemical staining, the tumor cells\nshowed patchy and intense immunoreactivity for CD10\n(Fig. 3a), estrogen receptor (Fig. 3e), and progesterone\nreceptor (Fig. 3f ), focal staining for CD99, and diffuse\nvimentin staining (Fig. 3b). Tumor cells also showed\nnegative results for CD117, S-100 protein, and CD34,\nCD31, D2-40, MDM2, pan-keratin, H-caldesmon (posi-\ntive in small vessels) (Fig. 3c), MNF116 (positive in the\nentrapped epithelial alveolar elements), TTF-1 (positive\nin the entrapped epithelial alveolar elements) (Fig. 3d),\nmyogenin and myoglobin. Ki67 percentage of positive\nFig. 1 Thoracic CT scan showing a mass (50 mm of maximum diameter) in the upper left lobe\nAlessandrini et al. Diagnostic Pathology  (2017) 12:36 Page 4 of 9\n\nnuclei ranged from 20 to 40%. Limited smooth muscle\ndifferentiation was occasionally present and was focally\npositive for smooth muscle actin and desmin. The\npreferred diagnosis was EESS with high grade areas.\nCD10 was completely negative (Fig. 4b) whereas estro-\ngen and progesterone receptors (Fig. 4c, d, respectively)\nwere positive, as expected, in leiomyomas from the pre-\nvious hysterectomy specimen.\nThe periscapular soft tissue recurrence showed the\nsame histological and immunohistochemical findings,\nexcept for the absence of staining for CD10, which dis-\nplayed a patchy staining on the lung specimen; therefore,\nits absence on a tru-cut biopsy of periscapular soft tis-\nsues could be due to sampling from a non-staining area.\nDiscussion\nEndometrial stromal sarcoma is a malignant tumor\nclosely resembling stromal cells of proliferative-phase\nendometrial stromal cells. It is commonly associated\nwith a delicate network of arterioles. Even when display-\ning classical histological features, an unusual site of oc-\ncurrence may make the diagnosis challenging. Therefore,\ndespite its rarity EESS should always be taken into con-\nsideration in the differential diagnosis for a woman with\na thoracic or abdominal tumor with uniform cytologic-\nally bland cells resembling normal endometrial stroma.\nOn the other hand, in the gastrointestinal tract and\nextragenital sites, in the absence of endometriosis EESSs\nmay be mistaken for other mesenchymal more common\nneoplasms [20], such as cellular leiomyoma and low-\ngrade leiomyosarcoma, solitary fibrous tumor and\ngastrointestinal stromal tumor (Table 2). In such cases, a\nlarge panel of immunohistochemical markers could be\nof help in establishing the diagnosis (Table 2). Regardless\nof the site of presentation, also peculiar histological\nfeatures may be challenging for diagnosis, when noted in\nEESS [22]. When tubules-like structures are identified\nwithin spindle cell proliferations, also endometriosis and\nadenosarcoma are additional diagnoses that should be\nconsidered. On the other hand, EESS also can have\nglandular differentiation. In this case periglandular stro-\nmal condensation around benign glands and polypoid\nfronds composed of cellular stroma imparting a leaf-like\nappearance are morphological features more characteristic\nof adenosarcoma.\nIn the largest group of EESS described to date, one\ncase arising in the larynx was initially diagnosed as\nmonophasic synovial sarcoma [22] which is not usually\nincluded into the differential diagnoses of EESS as it fre-\nquently arises within the soft tissues of the limbs. Immu-\nnohistochemistry can once again be helpful (Table 2).\nFinally, the long time from primary genital ESS onset\nFig. 2 a, b Panoramic view of the pulmonary lesion showing uniform spindle cells arranged in a fascicular pattern; alveolar epithelium is focally\nentrapped by the neoplastic cells (H&E, 100×); c, d some small thinwalled blood vessels resembling spiral arterioles of late secretory endometrium\nwere unevenly distributed among the stroma (H&E, 100×);b, d, neoplastic cells show moderate atypia and foci of hyaline-type necrosis, in a background of\nfibromyxoid stroma);d, the tumor cells had oval to plump spindle-shaped nuclei with finely granular chromatins, inconspicuous nucleoli, and amphophilic\ncytoplasms (H&E, 200×)\nAlessandrini et al. Diagnostic Pathology  (2017) 12:36 Page 5 of 9\n\nand its recurrence and/or metastasis, requires a review\nof the clinical history of the patient and a second look at\nthe slides from a previous hysterectomy specimen to\nrule out the possibility of an overlooked uterine ESS [2].\nIn our patient the hysterectomy specimen was exten-\nsively sampled and a review of all slides confirmed the\noriginal diagnosis.\nSeveral hypotheses are invoked to explain the patho-\ngenesis of EESS. Since in many cases (Table 1) endomet-\nriosis was found to be adjacent to EESS, it could be\nspeculated that primary EESS arises from an ectopic\nfocus of endometrial stroma. However, our case and few\nothers, (listed in Table 1), indicate that the absence of\nassociated endometriosis does not preclude primary\nEESS at that site. In these cases, either EESS may arise\nfrom an underlying endometriosis hidden by sarcomatous\novergrowth [22] or it might derive de novo from the\nperitoneal/pleural (in our case) surface or the coelomic or\nsubcoelomic multipotential epithelium [30, 31].\nRecent molecular studies showed that ESS can be\ngenetically heterogeneous. The most common alteration\ncarried by ESS is the t (7;17) (p15;q21) translocation,\nwhich results in JAZF1 – SUZ12 gene fusion (also known\nas JJAZ1) [32]. However, such rearrangements rarely\noccur in ESS displaying different morphological features\ne.g., myxoid, epithelioid, fibrous, smooth muscle, and\nsex-cord histologic variants: thisreveal that other un-\nknown molecular changes may be involved in the disease\nphenotypic presentation [32]. Other gene fusionscon-\ncerning PHF1 and YWHAE genes, are much less\nfrequent and are likely to be related with specific clinico-\npathological features [33]. Although molecular testing\nFig. 3 Neoplastic cells showed patchy and intense immunoreactivity for CD10 ( a, 100×), diffuse vimentin staining ( b, 100×), negative staining for\nH-Caldesmon (positive control staining in small vessels;upper left) ( c, 100×), negative staining for TTF-1 (positive nuclear staining in the entrapped\nepithelial alveolar elements; right) (d, 100×), moderately diffuse nuclear staining for estrogen receptor (e, 200×), moderately diffuse nuclear staining for\nprogesterone receptor (f,2 0 0 × )\nAlessandrini et al. Diagnostic Pathology  (2017) 12:36 Page 6 of 9\n\nfor the t (7;17) (p15;q21) and associated gene fusion may\nbe useful for confirming primary extrauterine endomet-\nrial stromal sarcoma, the low prevalence of the genetic\naberration in this subset of patients limits the clinical\nutility of the analysis [21].\nThe behavior of EESS, compared to genital ESS, seems\nto be controversial. Although results are conflicting, it\nseems that the only feature associated with a worse\nprognosis is the presence of morphological features sug-\ngestive of dedifferentiation [22].\nGiven the rarity of these tumors, evidence-based data\nare not available to help guide treatment decisions.\nSurgery is generally regarded as the cornerstone of treat-\nment for ESS. Complete cytoreductive surgery is recom-\nmended, especially in patients for whom this surgery\ncould result in being residual-disease-free. Tumor-free\nmargins are important in prognosis [34]. Extragenital\nESS may have a high tendency for dissemination and\nmetastasis in the omentum, mesentery, and abdominal\nor pelvic wall [20, 22]. Despite this, most patients with\nFig. 4 Leiomyoma with classic morphology from previous hysterectomy specimen, showing intersecting fascicles of cigarshaped, spindle cells with\neosinophilic cytoplasm (a, 200×); CD10 negative immunostaining (b, 200×); positive nuclear staining for estrogen receptor (c,2 0 0 × ) ,p o s i t i v en u c l e a r\nstaining for progesterone receptor (d,2 0 0 × )\nTable 2 Morphophenotypic features of the most common mesenchymal spindle cell neoplasms in the differential diagnosis of EESS\nMesenchymal Neoplasm Morphological features Immunohistochemical markers\nCellular leiomyoma/low-grade\nleiomyosarcoma\ncharacteristic intersecting fascicles of smooth muscle\ncigarshaped spindle cells with eosinophilic cytoplasm\nand perinuclear vacuolation, showing a smooth, pushing\nmargin and large, irregular, thick-walled blood vessels\nmuscle-specific actin +, smooth muscle actin +,\ndesmin +, ER +, PgR+, CD10 −/+, H-caldesmon +\nGastrointestinal stromal tumor spindle cells with long tapering nuclei and abundant\nclear or eosinophilic cytoplasm arranged in fascicles or\nsheets; characteristically well circumscribed with pushing\nborders\nCD34 +, DOG-1 +, CD117 +, CD10 -, ER -, PgR-;\nmuscle-specific actin −/+, smooth muscle actin\n−/+, desmin −/+,\nSolitary fibrous tumor bland spindle cells haphazardly arranged in a dense\ncollagenous matrix but lacks the peculiar characteristic\nvasculature of the ESS\nCD34 +, CD10 -, ER -, PgR-\nMonophasic synovial sarcoma most commonly involves the soft tissues of the extremities; CD99 +, EMA +, CD10 -, ER -, PgR-\nESS monomorphous plump spindle cells forming short regular\nfascicles, evenly distributed arterioles and infiltrative border\nmuscle-specific actin−/+, smooth muscle actin−/+,\ndesmin −/+, ER +, PgR+, CD10 +, H-caldesmon -\n- negativity, −/+ focal positivity, + diffuse positivity, ER estrogen receptor, PgR Progesteron receptor, EMA epithelial membrane antigen\nAlessandrini et al. Diagnostic Pathology  (2017) 12:36 Page 7 of 9\n\nextrauterine ESS had prolonged disease-free intervals\nwith late recurrences [20, 22]. The value of adjuvant\ntherapy is controversial with no prospective studies\nshowing a survival advantage associated with the use of\nchemotherapy or radiotherapy [34]. Nevertheless, adju-\nvant therapy is still considered in patients with meta-\nstatic or recurrent ESS. Radiotherapy may also have a\npalliative role [34].\nConclusions\nIn summary, we present in this study the first EESS of\nthe lung reported to date. EESS is an uncommon tumor\narising in women of any age, usually presents as a mass\nlesion in the abdomen or pelvic cavity. The knowledge\nof its potential extrauterine location and of peculiar\nmorphophenotypic aspects are required for a correct\ndiagnosis. Surgical resection is the most frequent treat-\nment option, eventually followed by hormonal-therapy.\nEESS does not seem to have an aggressive behavior, and\nis likely to recur late after the initial treatment: therefore,\na long-term clinical follow-up should be programmed.\nAbbreviations\nCT: Computed tomography; ESS: Endometrial stromal sarcoma; HGESS: High-grade\nendometrial stromal sarcoma; H&E: Hematoxylin-eosin; LGESS: Low-grade\nendometrial stromal sarcoma; UESS: Undifferentiated endometrial stromal sarcoma\nAcknowledgments\nWe thank Ms Laura Zannier and Ms Antonella Selva for their invaluable\ntechnical assistance and Ms Anna Vallerugo, MA, for the English editing.\nFunding\nNo funding was received for this case report.\nAvailability of data and materials\nPlease contact the Authors for data requests.\nAuthors’ contributions\nLA analyzed the data, reviewed the literature, took the pictures and wrote\nand revised the manuscript as a major contributor. VC performed the final\ndiagnosis on the revision of slides, interpreted the immunohistochemical staining of\nslides, wrote and revised the manuscript and contributes for important intellectual\ncontent. SS, FS, GM and GB gave information about clinical history and follow up; MU\ncontributed to the radiological findings and images. PT, GM helped to the final draft\nof the manuscript. GM, FS contributed to revision of the manuscript. FI contributed to\nliterature review. All authors have read and approved the final manuscript.\nCompeting interests\nThe authors declare that they have no competing interests.\nConsent for publication\nInformed consent was obtained from the patient for the publication of this\ncase report and any accompanying images.\nEthics approval and consent to participate\nEthical approval for this study was obtained from the Scientific Committee\nBoard of the Institute.\nPublisher’sN o t e\nSpringer Nature remains neutral with regard to jurisdictional claims in\npublished maps and institutional affiliations.\nAuthor details\n1Pathology, IRCCS-National Cancer Institute, Via F. Gallini 2, 33081 Aviano, Italy.\n2Gynecological Oncology Unit, IRCCS-National Cancer Institute, Aviano, Italy.\n3Surgical Oncology, IRCCS-National Cancer Institute, Aviano, Italy.4Department\nof Medical Oncology, IRCCS-National Cancer Institute, Aviano, Italy.\n5Department of Radiology, IRCCS-National Cancer Institute, Aviano, Italy.\n6Oncopath Lab, Floridia, Siracusa, Italy.\nReceived: 18 January 2017 Accepted: 17 April 2017\nReferences\n1. Kurman R, Carcangiu ML, Herrington C, et al. WHO classification of tumours\nof female reproductive organs. IARC WHO Classification of Tumours, No 6.\nLyon: IARC press; 2014.\n2. Oliva E, Clement PB, Young RH. Endometrial stromal tumors: an update on\na group of tumors with a protean phenotype. Adv Anat Pathol. 2000;7(5):\n257–81.\n3. Ferraro LR, Hetz H, Carter H. Malignant endometriosis; pelvic endometriosis\ncomplicated by polypoid endometrioma of the colon and endometriotic\nsarcoma; report of a case and review of the literature. 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Diagnostic Pathology  (2017) 12:36 Page 9 of 9","source_license":"CC0","license_restricted":false}