Primary pelvic synovial sarcoma: case report and review of the literature

Primary pelvic synovial sarcoma: case report and review of the literature | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Primary pelvic synovial sarcoma: case report and review of the literature Kaibing Xiao, Ying Yang, Zhiwei Li, Pang Yang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2477332/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Synovial sarcoma originating in the pelvis is an extremely rare malignancy, and only a few cases have been reported. Usually, the tumor is detected at an advanced stage, making treatment more difficult. Case presentation We admitted a 32-year-old male patient with MRI suggestive of an 8.2*7.7*8.9-cm mass in the pelvis with bleeding. After comprehensive evaluation, aggressive surgical treatment was performed, and postoperative pathology suggested biphasic synovial sarcoma, which was treated with regular chemotherapy in the oncology department. Ten months later, the patient was found to have recurrence of the tumor at the follow-up examination, and the patient is still alive. Conclusion Synovial sarcoma, a highly malignant soft tissue sarcoma, and primary intrapelvic synovial sarcoma is even rarer, with a poor prognosis. Ultrasound, CT and MRI can help specialists to detect the tumor at an early stage and treat it aggressively, especially by active surgical treatment, which can effectively improve the survival rate. Combined with the course of diagnosis and treatment of this case, it is possible to deepen the understanding of primary pelvic synovial sarcoma and discuss appropriate treatment strategies for this rare disease. pelvis synovial sarcoma hemorrhage case report Figures Figure 1 Figure 2 Introduction Synovial sarcoma is a relatively rare soft tissue sarcoma commonly found in the joints of the extremities and rarely in other areas. In general, the larger the tumor size is, the higher the risk of metastasis and recurrence will be, and tumors less than 5 cm in diameter have a good prognosis [ 1 , 2 ]. The aim of this study was to investigate the clinical, imaging and histological features and treatment of this rare tumor. Here, we report a case of primary pelvic synovial sarcoma. Case Presentation A 32-year-old male patient was admitted to the hospital with difficulty urinating and lower abdominal and perianal distension for three days. The patient was hospitalized with difficulty urinating and occasional pain at the end of urination, accompanied by pain in the lower abdomen and perianal area, with persistent distension and pain. There was no urinary frequency, no urinary urgency, no visible hematuria, and no fever. The patient did not pay enough attention and was not treated. His prostate-specific antigen, alpha-fetoprotein, and carcinoembryonic antigen were all within normal levels. Ultrasound of the abdomen indicates a mass in the lower posterior bladder. Magnetic resonance suggested an intrapelvic cavity mass, approximately 8.2*7.7*8.9-cm in size, with high, equal, and low mixed signals, locally visible cystic foci, and fluid planes, suggesting a tumorous lesion with possible hemorrhage and cystic changes (Fig. 1A-D). The pathological findings of the swelling puncture biopsy suggested a soft tissue spindle cell tumor. Surgical treatment was performed on March 20, 2021. Intraoperatively, a tiny amount of dark red bloody fluid was seen in the pelvis, and a solid cystic mass with a pseudo envelope behind the bladder was observed. A sinus duct of approximately 1*1 cm in size was seen on the upper surface inside the mass, and dark red blood and blood clots were spilling out. Removing the blood clots from the sinus duct opening, a large amount of bloody fluid, approximately 1100 ml, was seen leaking out, and the tumor was removed entirely. Postoperative pathology suggested pelvic synovial sarcoma, biphasic type (Fig. 2A-C); immunohistochemistry showed partial positivity for CK, weak positivity for CD99, and strong positivity for Bcl-2 (Fig. 2D-F). The patient was treated with regular chemotherapy with epirubicin and cyclophosphamide regimens. MRI was repeated in January 2022, suggesting tumor recurrence, and chemotherapy treatment was continued. It is now 20 months, and the patient is still alive. Discussion And Conclusion Synovial sarcoma is a rare soft tissue sarcoma with unclear differentiation, accounting for approximately 5–10% of all soft tissue sarcomas. It can occur in patients of any age but is commonly seen mainly in adolescents and young adults, with a median age at onset of approximately 39 years [ 3 , 4 ]. According to the statistics, the incidence of synovial sarcoma is 0.81/1,000,000 among children and 1.42/1,000,000 among adults [ 5 , 6 ]. It can occur anywhere in the body, though most often in the joints of the extremities, and presents as a growing soft tissue mass. Other areas, such as the oropharynx, larynx, mediastinum, lungs, kidneys, prostate, and abdominal wall, can also show synovial sarcoma growth [ 7 ]. Primary pelvic synovial sarcoma is even rarer and has been scarcely reported. The clinical manifestations of synovial sarcoma are not obvious. It is usually a slow-growing, painless mass, and when detected, the tumor has grown very large and shows symptoms of pressure on the surrounding organs [ 8 , 9 ]. Given the young age of onset, insidious course, and atypical clinical manifestations, it is easily misdiagnosed as a benign tumor, leading to treatment delay. In this case, the first symptom was the pressure of synovial sarcoma on the bladder, rectum, and other organs, which manifested as difficulty in urination and painful swelling in the lower abdomen and perianal area. The diagnosis of synovial sarcoma relies on imaging tests such as computed tomography and magnetic resonance. On computed tomography, the mass appears as a round or lobulated mass with a density similar to or slightly lower than that of muscle. It is heterogeneous and often accompanied by punctate peripheral calcifications [ 10 , 11 ]. Magnetic resonance is an imperative test to determine the diagnosis and staging of synovial sarcoma, and the imaging characteristics are diverse. Masses smaller than 5 cm appear as homogeneous masses on all sequences, favoring benign imaging features. Among sarcomas larger than 5 cm, there is significant heterogeneity. The heterogeneous mixed signal of the high, medium, and low intensities on T2WI, the so-called "triple signal sign", is due to calcification, cystic changes, hemorrhage, and fibrosis in the process of tumor growth [ 11 , 12 ]. The MRI of our patient showed a clear triple-signal sign, with bleeding and cystic changes visible inside the tumor, and the intraoperative views confirmed the presence of hemorrhage inside the cancer. In general, imaging is inadequate to confirm the diagnosis, and the final diagnosis is based on pathological findings. Synovial sarcomas are gray or yellowish-brown in appearance, and most are 3–10 cm in size [ 13 ]. Histologically, synovial sarcoma originates from mesenchymal cells and manifests as spindle cell sarcoma, which can be classified into monophasic, biphasic, and hypo-differentiated types according to the ratio of spindle cells to epithelial cells. The monophasic type is the most common type, accounting for approximately 50–60% of all synovial sarcomas and consisting of only spindle cells. This is followed by biphasic synovial sarcoma, which makes up approximately 20–30% of all synovial sarcomas and comprises both epithelial and spindle cells. Poorly differentiated synovial sarcoma is the least common type, accounting for 10–15% of cases [ 14 ]. In our patient, preoperative mass puncture biopsy suggested soft tissue spindle cell sarcoma, and postoperative gross specimen pathology indicated a biphasic synovial sarcoma with the coexistence of epithelial cells and spindle cells. Immunohistochemistry was positive for EMA, CK, CK19, CD99, and Bcl-2 protein and negative for S100 protein. Molecularly genetically expressed as t(X:18) translocations, including the common SS18:SSX1 and SS18:SSX2 and the less common SS18:SSX4 translocations, this translocation is present only in synovial sarcoma and is seen in approximately 95% of cases[ 15 – 17 ]. Fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction (RT‒PCR) assays can confirm this translocation. Of course, the diagnosis of synovial sarcoma cannot be excluded in patients with no detectable t(X:18) translocation and imaging showing synovial sarcoma features (approximately 5% of all patients), as this group of patients may be associated with t(X;20) and SS18L1-SSX1 fusion transcripts [ 18 ]. Because of the rarity of synovial sarcoma, no standard treatment regimens are currently available. Surgery is still the preferred treatment modality according to the age of onset, location, and tumor size. Complete resection of the tumor is the key to reducing postoperative recurrence and improving survival. Postoperative supplementation with systematic radiotherapy can improve the treatment effect based on the characteristics of the case [ 19 , 20 ]. In conclusion, Synovial sarcoma, a highly malignant soft tissue sarcoma, and primary intrapelvic synovial sarcoma is even rarer, with a poor prognosis. Ultrasound, CT and MRI can help specialists to detect the tumor at an early stage and treat it aggressively, especially by active surgical treatment, which can effectively improve the survival rate. Combined with the course of diagnosis and treatment of this case, it is possible to deepen the understanding of primary pelvic synovial sarcoma and discuss appropriate treatment strategies for this rare disease. Declarations Ethics approval As it is a case report, ethics approval is not necessary after consulting the Ethics Committee of Nan Chang First Hospital. Consent to participate The patient agreed to participate in our study and signed an informed consent prior. Consent for publication Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal. Availability of data and materials All data and figure generated or analyzed during this study are included in this published article. Conflicts of interest The authors declare no competing financial interests. Funding No financial support was received for this submission. Author contributions Kaibing Xiao, Pang Yang designed the study; Kaibing Xiao, Ying Yang completed the data collection and collation; Kaibing Xiao, Zhiwei Li helped in literature search and wrote the paper; Pang Yang made critical revision and supervision. Kaibing Xiao, Ying Yang, Zhiwei Li have equally contributed to this work. All authors have read and approved the manuscript. Acknowledgements We would like to thank the patient for his participation and his consent to the publication of the case details and associated images. References Przybyl J, Sciot R, Wozniak A, Schöffski P, Vanspauwen V, Samson I, Siedlecki JA, Rutkowski P, Debiec-Rychter M. Metastatic potential is determined early in synovial sarcoma development and reflected by tumor molecular features. The international journal of biochemistry & cell biology. 2014, 53:505-513. Naing KW, Monjazeb AM, Li CS, Lee LY, Yang A, Borys D, Canter RJ. Perioperative radiotherapy is associated with improved survival among patients with synovial sarcoma: A SEER analysis. Journal of surgical oncology. 2015, 111(2):158-164. Aytekin MN, Öztürk R, Amer K, Yapar A. Epidemiology, incidence, and survival of synovial sarcoma subtypes: SEER database analysis. Journal of orthopaedic surgery (Hong Kong). 2020, 28(2):2309499020936009. Thway K, Fisher C: Synovial sarcoma. defining features and diagnostic evolution. Annals of diagnostic pathology. 2014, 18(6):369-380. Sultan I, Rodriguez-Galindo C, Saab R, Yasir S, Casanova M, Ferrari A. Comparing children and adults with synovial sarcoma in the Surveillance, Epidemiology, and End Results program, 1983 to 2005: an analysis of 1268 patients. Cancer. 2009, 115(15):3537-3547. Gazendam AM, Popovic S, Munir S, Parasu N, Wilson D, Ghert M. Synovial Sarcoma: A Clinical Review. Current oncology (Toronto, Ont). 2021, 28(3):1909-1920. Caracciolo JT, Henderson-Jackson E, Binitie O. Synovial sarcoma of bone: Sarcoma typically of soft tissues presenting as a primary bone tumor. Radiology case reports. 2019, 14(2):204-207. Fiore M, Sambri A, Spinnato P, Zucchini R, Giannini C, Caldari E, Pirini MG, De Paolis M. The Biology of Synovial Sarcoma: State-of-the-Art and Future Perspectives. Current treatment options in oncology. 2021, 22(12):109. Smolle MA, Parry M, Jeys L, Abudu S, Grimer R. Synovial sarcoma: Do children do better? European journal of surgical oncology : the journal of the European Society of Surgical Oncology and the British Association of Surgical Oncology. 2019, 45(2):254-260. Baheti AD, Tirumani SH, Sewatkar R, Shinagare AB, Hornick JL, Ramaiya NH, Jagannathan JP. Imaging features of primary and metastatic extremity synovial sarcoma: a single institute experience of 78 patients. The British journal of radiology. 2015, 88(1046):20140608. O'Sullivan PJ, Harris AC, Munk PL. Radiological features of synovial cell sarcoma. The British journal of radiology. 2008, 81(964):346-356. Liang C, Mao H, Tan J, Ji Y, Sun F, Dou W, Wang H, Wang H, Gao J. Synovial sarcoma: Magnetic resonance and computed tomography imaging features and differential diagnostic considerations. Oncology letters. 2015, 9(2):661-666. Jo VY, Fletcher CD. WHO classification of soft tissue tumours: an update based on the 2013 (4th) edition. Pathology. 2014, 46(2):95-104. Xiong L, Chen Z, Zhou Y, Li H, Xiao T. The survival and prognosis analysis of synovial sarcoma subtypes: a Surveillance, Epidemiology, and End Results population-based analysis. International orthopaedics. 2020, 44(12):2779-2786. Kuruva SP, Bala S, Konatam ML, Karnam AK, Maddali LS, Gundeti S. Clinicopathological features, treatment and survival outcomes of synovial sarcoma. South Asian journal of cancer. 2018, 7(4):270-272. Stacchiotti S, Van Tine BA. Synovial Sarcoma: Current Concepts and Future Perspectives. Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 2018, 36(2):180-187. Nielsen TO, Poulin NM, Ladanyi M. Synovial sarcoma: recent discoveries as a roadmap to new avenues for therapy. Cancer discovery. 2015, 5(2):124-134. Storlazzi CT, Mertens F, Mandahl N, Gisselsson D, Isaksson M, Gustafson P, Domanski HA, Panagopoulos I. A novel fusion gene, SS18L1/SSX1, in synovial sarcoma. Genes, chromosomes & cancer. 2003, 37(2):195-200. Wang Y, Delisle M, Smith D, Alshamsan B, Srikanthan A. Metastasectomy in synovial sarcoma: A systematic review and meta-analysis. European journal of surgical oncology : the journal of the European Society of Surgical Oncology and the British Association of Surgical Oncology. 2022, 48(9):1901-1910. von Mehren M, Randall RL, Benjamin RS, Boles S, Bui MM, Conrad EU, 3rd, Ganjoo KN, George S, Gonzalez RJ, Heslin MJ et al. Soft Tissue Sarcoma, Version 2.2016, NCCN Clinical Practice Guidelines in Oncology. Journal of the National Comprehensive Cancer Network : JNCCN .2016, 14(6):758-786. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-2477332","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":169508901,"identity":"61d4c496-c172-4b4e-b4e8-448d8129ff2b","order_by":0,"name":"Kaibing Xiao","email":"","orcid":"","institution":"The First Hospital of Nanchang","correspondingAuthor":false,"prefix":"","firstName":"Kaibing","middleName":"","lastName":"Xiao","suffix":""},{"id":169508904,"identity":"a3e79307-e4fb-4a0d-bd36-e67b17746c80","order_by":1,"name":"Ying Yang","email":"","orcid":"","institution":"The First Hospital of Nanchang","correspondingAuthor":false,"prefix":"","firstName":"Ying","middleName":"","lastName":"Yang","suffix":""},{"id":169508906,"identity":"57f65c59-76c0-4360-ac99-cc302e08155c","order_by":2,"name":"Zhiwei Li","email":"","orcid":"","institution":"Suzhou Kowloon Hospital, Shanghai Jiaotong University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Zhiwei","middleName":"","lastName":"Li","suffix":""},{"id":169508907,"identity":"1e3f4d7a-9163-4a5a-8c6e-35a84eb754f1","order_by":3,"name":"Pang Yang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyklEQVRIiWNgGAWjYNCCHzZy/MzMhx8Qr4OxJ81Ysp0tzYAEW9gOJ244z6MgQZRic4nkZw+/8Bxm3HyYh8GAocYmmqAWyxlp5sYyFunMZod5DzxgOJaW20BIi8GNBDNpCR5rNrPDfAkGjA2HidGS/k1ago2Zx7iZx0CCSC05ZpIf2JwlDJiJ1WLZ86ZMGhjIBhKHgYGcQIxfzNnTt0n++GFT399/+PCDDzU2RDhMIIGBmQfGSyCkHKyF/wAD4w9iVI6CUTAKRsHIBQCnRDyox9D67QAAAABJRU5ErkJggg==","orcid":"","institution":"The First Hospital of Nanchang","correspondingAuthor":true,"prefix":"","firstName":"Pang","middleName":"","lastName":"Yang","suffix":""}],"badges":[],"createdAt":"2023-01-14 06:59:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2477332/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2477332/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":31954809,"identity":"5c284f11-fa96-471f-b343-4078ed7063eb","added_by":"auto","created_at":"2023-01-23 15:42:06","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":157971,"visible":true,"origin":"","legend":"\u003cp\u003eA-C: Intrapelvic masses were observed in coronal, sagittal and transverse views on MRI T1 sequences. D: The coexistence of high, medium and low signals on the MRI DWI sequence, namely, the \"triple signal sign\".\u003c/p\u003e","description":"","filename":"Figure1.Tif.png","url":"https://assets-eu.researchsquare.com/files/rs-2477332/v1/4c1b03d769fc1b989bc38f23.png"},{"id":31954351,"identity":"c05706d2-d9f9-4677-ba2d-9a960402d24b","added_by":"auto","created_at":"2023-01-23 15:34:06","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":428179,"visible":true,"origin":"","legend":"\u003cp\u003eA: Tumors consist of a mixture of spindle cells and epithelial components (H \u0026amp; E, magnification 40×). B: The epithelial components are arranged in a glandular duct-like pattern, and the glandular lumen contains eosinophilic secretions (H \u0026amp; E, magnification 100×). C: The spindle cells were dense and long- or fat-spindle shaped, and nuclear schisis was visible (H \u0026amp; E, magnification 200×). D-F: Immunohistochemistry was partially positive for CK, weakly positive for CD99, and strongly positive for Bcl-2.\u003c/p\u003e","description":"","filename":"Figure2.Tif.png","url":"https://assets-eu.researchsquare.com/files/rs-2477332/v1/832529460ebeb953036e49de.png"},{"id":33879927,"identity":"3a56a426-e846-4431-bb94-9d768d28ef3e","added_by":"auto","created_at":"2023-03-07 06:14:40","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":855954,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2477332/v1/10bc2f39-a35b-4bbe-bd8b-bf03487e0117.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Primary pelvic synovial sarcoma: case report and review of the literature","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSynovial sarcoma is a relatively rare soft tissue sarcoma commonly found in the joints of the extremities and rarely in other areas. In general, the larger the tumor size is, the higher the risk of metastasis and recurrence will be, and tumors less than 5 cm in diameter have a good prognosis [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. The aim of this study was to investigate the clinical, imaging and histological features and treatment of this rare tumor. Here, we report a case of primary pelvic synovial sarcoma.\u003c/p\u003e"},{"header":"Case Presentation","content":"\u003cp\u003eA 32-year-old male patient was admitted to the hospital with difficulty urinating and lower abdominal and perianal distension for three days. The patient was hospitalized with difficulty urinating and occasional pain at the end of urination, accompanied by pain in the lower abdomen and perianal area, with persistent distension and pain. There was no urinary frequency, no urinary urgency, no visible hematuria, and no fever. The patient did not pay enough attention and was not treated. His prostate-specific antigen, alpha-fetoprotein, and carcinoembryonic antigen were all within normal levels. Ultrasound of the abdomen indicates a mass in the lower posterior bladder. Magnetic resonance suggested an intrapelvic cavity mass, approximately 8.2*7.7*8.9-cm in size, with high, equal, and low mixed signals, locally visible cystic foci, and fluid planes, suggesting a tumorous lesion with possible hemorrhage and cystic changes (Fig.\u0026nbsp;1A-D). The pathological findings of the swelling puncture biopsy suggested a soft tissue spindle cell tumor. Surgical treatment was performed on March 20, 2021. Intraoperatively, a tiny amount of dark red bloody fluid was seen in the pelvis, and a solid cystic mass with a pseudo envelope behind the bladder was observed. A sinus duct of approximately 1*1 cm in size was seen on the upper surface inside the mass, and dark red blood and blood clots were spilling out. Removing the blood clots from the sinus duct opening, a large amount of bloody fluid, approximately 1100 ml, was seen leaking out, and the tumor was removed entirely. Postoperative pathology suggested pelvic synovial sarcoma, biphasic type (Fig.\u0026nbsp;2A-C); immunohistochemistry showed partial positivity for CK, weak positivity for CD99, and strong positivity for Bcl-2 (Fig.\u0026nbsp;2D-F). The patient was treated with regular chemotherapy with epirubicin and cyclophosphamide regimens. MRI was repeated in January 2022, suggesting tumor recurrence, and chemotherapy treatment was continued. It is now 20 months, and the patient is still alive.\u003c/p\u003e"},{"header":"Discussion And Conclusion","content":"\u003cp\u003eSynovial sarcoma is a rare soft tissue sarcoma with unclear differentiation, accounting for approximately 5\u0026ndash;10% of all soft tissue sarcomas. It can occur in patients of any age but is commonly seen mainly in adolescents and young adults, with a median age at onset of approximately 39 years [\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e4\u003c/span\u003e]. According to the statistics, the incidence of synovial sarcoma is 0.81/1,000,000 among children and 1.42/1,000,000 among adults [\u003cspan class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e6\u003c/span\u003e]. It can occur anywhere in the body, though most often in the joints of the extremities, and presents as a growing soft tissue mass. Other areas, such as the oropharynx, larynx, mediastinum, lungs, kidneys, prostate, and abdominal wall, can also show synovial sarcoma growth [\u003cspan class=\"CitationRef\"\u003e7\u003c/span\u003e]. Primary pelvic synovial sarcoma is even rarer and has been scarcely reported.\u003c/p\u003e\n\u003cp\u003eThe clinical manifestations of synovial sarcoma are not obvious. It is usually a slow-growing, painless mass, and when detected, the tumor has grown very large and shows symptoms of pressure on the surrounding organs [\u003cspan class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e9\u003c/span\u003e]. Given the young age of onset, insidious course, and atypical clinical manifestations, it is easily misdiagnosed as a benign tumor, leading to treatment delay. In this case, the first symptom was the pressure of synovial sarcoma on the bladder, rectum, and other organs, which manifested as difficulty in urination and painful swelling in the lower abdomen and perianal area.\u003c/p\u003e\n\u003cp\u003eThe diagnosis of synovial sarcoma relies on imaging tests such as computed tomography and magnetic resonance. On computed tomography, the mass appears as a round or lobulated mass with a density similar to or slightly lower than that of muscle. It is heterogeneous and often accompanied by punctate peripheral calcifications [\u003cspan class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e11\u003c/span\u003e]. Magnetic resonance is an imperative test to determine the diagnosis and staging of synovial sarcoma, and the imaging characteristics are diverse. Masses smaller than 5 cm appear as homogeneous masses on all sequences, favoring benign imaging features. Among sarcomas larger than 5 cm, there is significant heterogeneity. The heterogeneous mixed signal of the high, medium, and low intensities on T2WI, the so-called \u0026quot;triple signal sign\u0026quot;, is due to calcification, cystic changes, hemorrhage, and fibrosis in the process of tumor growth [\u003cspan class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e12\u003c/span\u003e]. The MRI of our patient showed a clear triple-signal sign, with bleeding and cystic changes visible inside the tumor, and the intraoperative views confirmed the presence of hemorrhage inside the cancer.\u003c/p\u003e\n\u003cp\u003eIn general, imaging is inadequate to confirm the diagnosis, and the final diagnosis is based on pathological findings. Synovial sarcomas are gray or yellowish-brown in appearance, and most are 3\u0026ndash;10 cm in size [\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e]. Histologically, synovial sarcoma originates from mesenchymal cells and manifests as spindle cell sarcoma, which can be classified into monophasic, biphasic, and hypo-differentiated types according to the ratio of spindle cells to epithelial cells. The monophasic type is the most common type, accounting for approximately 50\u0026ndash;60% of all synovial sarcomas and consisting of only spindle cells. This is followed by biphasic synovial sarcoma, which makes up approximately 20\u0026ndash;30% of all synovial sarcomas and comprises both epithelial and spindle cells. Poorly differentiated synovial sarcoma is the least common type, accounting for 10\u0026ndash;15% of cases [\u003cspan class=\"CitationRef\"\u003e14\u003c/span\u003e]. In our patient, preoperative mass puncture biopsy suggested soft tissue spindle cell sarcoma, and postoperative gross specimen pathology indicated a biphasic synovial sarcoma with the coexistence of epithelial cells and spindle cells. Immunohistochemistry was positive for EMA, CK, CK19, CD99, and Bcl-2 protein and negative for S100 protein.\u003c/p\u003e\n\u003cp\u003eMolecularly genetically expressed as t(X:18) translocations, including the common SS18:SSX1 and SS18:SSX2 and the less common SS18:SSX4 translocations, this translocation is present only in synovial sarcoma and is seen in approximately 95% of cases[\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e17\u003c/span\u003e]. Fluorescence in situ hybridization (FISH) and reverse transcription polymerase chain reaction (RT‒PCR) assays can confirm this translocation. Of course, the diagnosis of synovial sarcoma cannot be excluded in patients with no detectable t(X:18) translocation and imaging showing synovial sarcoma features (approximately 5% of all patients), as this group of patients may be associated with t(X;20) and SS18L1-SSX1 fusion transcripts [\u003cspan class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e\n\u003cp\u003eBecause of the rarity of synovial sarcoma, no standard treatment regimens are currently available. Surgery is still the preferred treatment modality according to the age of onset, location, and tumor size. Complete resection of the tumor is the key to reducing postoperative recurrence and improving survival. Postoperative supplementation with systematic radiotherapy can improve the treatment effect based on the characteristics of the case [\u003cspan class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e\n\u003cp\u003eIn conclusion, Synovial sarcoma, a highly malignant soft tissue sarcoma, and primary intrapelvic synovial sarcoma is even rarer, with a poor prognosis. Ultrasound, CT and MRI can help specialists to detect the tumor at an early stage and treat it aggressively, especially by active surgical treatment, which can effectively improve the survival rate. Combined with the course of diagnosis and treatment of this case, it is possible to deepen the understanding of primary pelvic synovial sarcoma and discuss appropriate treatment strategies for this rare disease.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eEthics approval\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAs it is a case report, ethics approval is not necessary after consulting the\u0026nbsp;Ethics Committee of\u0026nbsp;Nan Chang\u0026nbsp;First\u0026nbsp;Hospital.\u003c/p\u003e\n\u003cp\u003eConsent to participate\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe patient agreed to participate in our study and signed an informed consent prior. Consent for publication\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWritten informed consent was obtained from the\u0026nbsp;patient for publication of this case report and\u0026nbsp;accompanying images. A copy of the written consent is\u0026nbsp;available for review by the Editor-in-Chief of this journal.\u003c/p\u003e\n\u003cp\u003eAvailability of data and materials\u003c/p\u003e\n\u003cp\u003eAll data and figure generated or analyzed during this study are included in this published article.\u003c/p\u003e\n\u003cp\u003eConflicts of interest\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing\u0026nbsp;financial\u0026nbsp;interests.\u003c/p\u003e\n\u003cp\u003eFunding\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eNo financial support was received for this submission.\u003c/p\u003e\n\u003cp\u003eAuthor contributions\u0026nbsp;\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eKaibing Xiao, Pang Yang designed the study; Kaibing Xiao, Ying Yang completed the data collection and collation; Kaibing Xiao, Zhiwei Li helped in literature search and wrote the paper; Pang Yang made critical revision and supervision. Kaibing Xiao,\u0026nbsp;Ying Yang,\u0026nbsp;Zhiwei Li\u0026nbsp;have equally contributed to this work.\u0026nbsp;All authors have read and approved the manuscript.\u003c/p\u003e\n\u003cp\u003eAcknowledgements\u0026nbsp;\u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWe would like to thank the patient for his participation and his consent to the publication of the case details and associated images.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003ePrzybyl J, Sciot R, Wozniak A, Sch\u0026ouml;ffski P, Vanspauwen V, Samson I, Siedlecki JA, Rutkowski P, Debiec-Rychter M. Metastatic potential is determined early in synovial sarcoma development and reflected by tumor molecular features. The international journal of biochemistry \u0026amp; cell biology. 2014, 53:505-513.\u003c/li\u003e\n\u003cli\u003eNaing KW, Monjazeb AM, Li CS, Lee LY, Yang A, Borys D, Canter RJ. Perioperative radiotherapy is associated with improved survival among patients with synovial sarcoma: A SEER analysis. Journal of surgical oncology. 2015, 111(2):158-164.\u003c/li\u003e\n\u003cli\u003eAytekin MN, \u0026Ouml;zt\u0026uuml;rk R, Amer K, Yapar A. Epidemiology, incidence, and survival of synovial sarcoma subtypes: SEER database analysis. Journal of orthopaedic surgery (Hong Kong). 2020, 28(2):2309499020936009.\u003c/li\u003e\n\u003cli\u003eThway K, Fisher C: Synovial sarcoma. defining features and diagnostic evolution. Annals of diagnostic pathology. 2014, 18(6):369-380.\u003c/li\u003e\n\u003cli\u003eSultan I, Rodriguez-Galindo C, Saab R, Yasir S, Casanova M, Ferrari A. Comparing children and adults with synovial sarcoma in the Surveillance, Epidemiology, and End Results program, 1983 to 2005: an analysis of 1268 patients. Cancer. 2009, 115(15):3537-3547.\u003c/li\u003e\n\u003cli\u003eGazendam AM, Popovic S, Munir S, Parasu N, Wilson D, Ghert M. Synovial Sarcoma: A Clinical Review. Current oncology (Toronto, Ont). 2021, 28(3):1909-1920.\u003c/li\u003e\n\u003cli\u003eCaracciolo JT, Henderson-Jackson E, Binitie O. Synovial sarcoma of bone: Sarcoma typically of soft tissues presenting as a primary bone tumor. Radiology case reports. 2019, 14(2):204-207.\u003c/li\u003e\n\u003cli\u003eFiore M, Sambri A, Spinnato P, Zucchini R, Giannini C, Caldari E, Pirini MG, De Paolis M. The Biology of Synovial Sarcoma: State-of-the-Art and Future Perspectives. Current treatment options in oncology. 2021, 22(12):109.\u003c/li\u003e\n\u003cli\u003eSmolle MA, Parry M, Jeys L, Abudu S, Grimer R. Synovial sarcoma: Do children do better? European journal of surgical oncology : the journal of the European Society of Surgical Oncology and the British Association of Surgical Oncology. 2019, 45(2):254-260.\u003c/li\u003e\n\u003cli\u003eBaheti AD, Tirumani SH, Sewatkar R, Shinagare AB, Hornick JL, Ramaiya NH, Jagannathan JP. Imaging features of primary and metastatic extremity synovial sarcoma: a single institute experience of 78 patients. The British journal of radiology. 2015, 88(1046):20140608.\u003c/li\u003e\n\u003cli\u003eO\u0026apos;Sullivan PJ, Harris AC, Munk PL. Radiological features of synovial cell sarcoma. The British journal of radiology. 2008, 81(964):346-356.\u003c/li\u003e\n\u003cli\u003eLiang C, Mao H, Tan J, Ji Y, Sun F, Dou W, Wang H, Wang H, Gao J. Synovial sarcoma: Magnetic resonance and computed tomography imaging features and differential diagnostic considerations. Oncology letters. 2015, 9(2):661-666.\u003c/li\u003e\n\u003cli\u003eJo VY, Fletcher CD. WHO classification of soft tissue tumours: an update based on the 2013 (4th) edition. Pathology. 2014, 46(2):95-104.\u003c/li\u003e\n\u003cli\u003eXiong L, Chen Z, Zhou Y, Li H, Xiao T. The survival and prognosis analysis of synovial sarcoma subtypes: a Surveillance, Epidemiology, and End Results population-based analysis. International orthopaedics. 2020, 44(12):2779-2786.\u003c/li\u003e\n\u003cli\u003eKuruva SP, Bala S, Konatam ML, Karnam AK, Maddali LS, Gundeti S. Clinicopathological features, treatment and survival outcomes of synovial sarcoma. South Asian journal of cancer. 2018, 7(4):270-272.\u003c/li\u003e\n\u003cli\u003eStacchiotti S, Van Tine BA. Synovial Sarcoma: Current Concepts and Future Perspectives. Journal of clinical oncology : official journal of the American Society of Clinical Oncology. 2018, 36(2):180-187.\u003c/li\u003e\n\u003cli\u003eNielsen TO, Poulin NM, Ladanyi M. Synovial sarcoma: recent discoveries as a roadmap to new avenues for therapy. Cancer discovery. 2015, 5(2):124-134.\u003c/li\u003e\n\u003cli\u003eStorlazzi CT, Mertens F, Mandahl N, Gisselsson D, Isaksson M, Gustafson P, Domanski HA, Panagopoulos I. A novel fusion gene, SS18L1/SSX1, in synovial sarcoma. Genes, chromosomes \u0026amp; cancer. 2003, 37(2):195-200.\u003c/li\u003e\n\u003cli\u003eWang Y, Delisle M, Smith D, Alshamsan B, Srikanthan A. Metastasectomy in synovial sarcoma: A systematic review and meta-analysis. European journal of surgical oncology : the journal of the European Society of Surgical Oncology and the British Association of Surgical Oncology. 2022, 48(9):1901-1910.\u003c/li\u003e\n\u003cli\u003evon Mehren M, Randall RL, Benjamin RS, Boles S, Bui MM, Conrad EU, 3rd, Ganjoo KN, George S, Gonzalez RJ, Heslin MJ et al. Soft Tissue Sarcoma, Version 2.2016, NCCN Clinical Practice Guidelines in Oncology. Journal of the National Comprehensive Cancer Network : JNCCN .2016, 14(6):758-786.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"pelvis, synovial sarcoma, hemorrhage, case report","lastPublishedDoi":"10.21203/rs.3.rs-2477332/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2477332/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSynovial sarcoma originating in the pelvis is an extremely rare malignancy, and only a few cases have been reported. Usually, the tumor is detected at an advanced stage, making treatment more difficult.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase presentation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe admitted a 32-year-old male patient with MRI suggestive of an 8.2*7.7*8.9-cm mass in the pelvis with bleeding. After comprehensive evaluation, aggressive surgical treatment was performed, and postoperative pathology suggested biphasic synovial sarcoma, which was treated with regular chemotherapy in the oncology department. Ten months later, the patient was found to have recurrence of the tumor at the follow-up examination, and the patient is still alive.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSynovial sarcoma, a highly malignant soft tissue sarcoma, and primary intrapelvic synovial sarcoma is even rarer, with a poor prognosis. Ultrasound, CT and MRI can help specialists to detect the tumor at an early stage and treat it aggressively, especially by active surgical treatment, which can effectively improve the survival rate. Combined with the course of diagnosis and treatment of this case, it is possible to deepen the understanding of primary pelvic synovial sarcoma and discuss appropriate treatment strategies for this rare disease.\u003c/p\u003e","manuscriptTitle":"Primary pelvic synovial sarcoma: case report and review of the literature","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-01-23 15:34:02","doi":"10.21203/rs.3.rs-2477332/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"7040180c-6f37-4527-878f-29df758f7259","owner":[],"postedDate":"January 23rd, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2023-11-08T23:29:12+00:00","versionOfRecord":[],"versionCreatedAt":"2023-01-23 15:34:02","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-2477332","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2477332","identity":"rs-2477332","version":["v1"]},"buildId":"_2-kVJe1T_tPrBINL-cwx","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}