When Sarcoma Strikes the Jaw: A Rare Case of Intraosseous Synovial Sarcoma

When Sarcoma Strikes the Jaw: A Rare Case of Intraosseous Synovial Sarcoma | 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 When Sarcoma Strikes the Jaw: A Rare Case of Intraosseous Synovial Sarcoma Rajat Choudhari, Yashasvi Patel, Pinakin Patel, Kamal Kishor Lakhera, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7151019/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 29 Nov, 2025 Read the published version in SN Comprehensive Clinical Medicine → Version 1 posted 14 You are reading this latest preprint version Abstract Introduction Synovial sarcoma (SS) is a malignant soft tissue tumor of uncertain histogenesis which forms 5–10% of all soft tissue sarcomas and most commonly presents in the extremities. SS of the head and neck region forms 6–7% of all cases and most common site is the hypopharynx, parapharyngeal spaces and posterior pharyngeal wall. We report a rare case of primary synovial sarcoma arising from the mandibular bone treated with surgical resection and adjuvant radiotherapy. Case presentation A 52-year-old gentleman presented with a 6-month history of swelling in the left lower jaw associated with dull pain and loosening of teeth which, on examination, was revealed to be a 6 x 4 cm mass in the left mandibular region. CECT revealed an ill-defined heterogenous soft tissue lesion of 52 x 39 mm in the left lower mandible with destruction of the bone. Incisional biopsy showed plump spindly cells positive for CK, vimentin, Bcl2 and TLE-1 and negative for P63, P40, caldesmon, SMA, HMB45, S100 and beta-catenin confirming synovial sarcoma. The patient underwent wide local excision of the tumor with enbloc segmental mandibulectomy and supra-omohyoid neck dissection with fibular osteocutaneous free flap reconstruction. Due to the high-grade nature of SS, the tumor bed and neck was treated with adjuvant radiotherapy (50.4 Gy in 25 fractions). Conclusion Primary synovial sarcoma of the mandible is rare and carries poor prognosis. Histological confirmation is possible through immunohistochemistry and genetic testing. Surgical resection is the mainstay of treatment with radiotherapy reserved for aggressive cases Synovial sarcoma intraosseous sarcoma jaw tumors synovial sarcoma of jaw Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Synovial sarcoma (SS) is a malignant soft tissue tumor of uncertain histogenesis which may present with varied epithelial differentiation. It forms 5–10% of all soft tissue sarcomas and most commonly presents in the extremities [ 1 ]. It usually occurs in joint capsules and tendinous regions but relation to synovium may not always be present. SS of the head and neck region forms 6–7% of all cases and most common site of synovial sarcoma in the head and neck region is the hypopharynx, parapharyngeal spaces and posterior pharyngeal wall. Due to the pluripotent cell of origin, they can also arise in intraosseous locations, albeit rarely, in the oral cavity but nonetheless carrying worse prognosis [ 2 ]. We report a rare case of primary synovial sarcoma arising from the mandibular bone treated with surgical resection and adjuvant radiotherapy. Case presentation A 52-year-old gentleman presented to our oncology department with a 6-month history of swelling in the left lower jaw associated with dull pain and loosening of teeth which had recently ulcerated through the skin with mucoid discharge. On local examination, he was found to have a poor dental hygiene with partial loss of dentition and a 6 x 4 cm mass in the left mandibular region with normal overlying mucosa and gingivobuccal sulcus (GBS) and ulceration over the inferior aspect of skin with purulent discharge (Fig. 1 ). Contrast enhanced Computerized tomography (CECT) revealed an ill-defined heterogenous soft tissue lesion of 52 x 39 mm in the left lower mandible with destruction of the bone and obliteration of the GBS (Fig. 2 ). Incisional biopsy showed plump spindly cells with hyperchromatic nuclei arranged in haphazard fascicles with a differential of high-grade sarcoma or sarcomatoid variant of squamous cell carcinoma due to the intraoral location of tumor. On immunohistochemistry (IHC), the tumor cells were found to be positive for CK, vimentin, Bcl2 and TLE-1 and negative for P63, P40, caldesmon, SMA, HMB45, S100 and beta-catenin confirming synovial sarcoma. The patient underwent wide local excision of the tumor with enbloc segmental mandibulectomy and supra-omohyoid neck dissection with fibular osteocutaneous free flap reconstruction (Fig. 3 ). The surgical histopathology confirmed the biopsy diagnosis with negative margins and one positive lymph node out of 15. The post operative period was uneventful. Due to the high-grade nature of SS, the tumor bed and neck was treated with adjuvant radiotherapy (50.4 Gy in 25 fractions). The patient tolerated the treatment with minimal toxicity. He was found to be disease free with good oral function at 6 months follow up (Fig. 4 ). Discussion and conclusion Synovial sarcoma (SS) arises from pluripotent mesenchymal cells and is generally considered a high-grade sarcoma. Although 70% of these cases present in the extremities, a good chunk can virtually arise from any tissue and location in the body. SS has been described in various parts of the oral cavity including tongue, palate, maxilla, gingiva and mandible [ 3 ]. Due to the cell of origin being pluripotent mesenchymal cells, intraosseous origin is also possible. Rare sites in the head and neck region such as the temporomandibular joint (TMJ), coronoid process of mandible and occipital bone have been reported in the literature [ 4 ]. Due to its propensity to arise in para-articular regions, SS is infrequent in the mandibular and maxillary bodies as compared to TMJ. Imaging can prove to be unreliable to make an accurate diagnosis, nonetheless, some classical features may cast light on the likelihood of its presence. A panoramic radiograph of the mandible shows a multiocular radiolucent lytic lesion within the body of the mandible with cortical plate expansion. CECT is a better modality to determine the exact extent of tissue and bony involvement. SS can have four histological variants including i) monophasic spindle cell, ii) monophasic epithelioid iii) biphasic and iv) poorly differentiated or ossifying types. Diagnosis is made on biopsy but may prove to be difficult in cases of poorly differentiated and monophasic subtypes whereas the biphasic form may be reliably confirmed. They require IHC and molecular testing for confirmation. The monophasic variant has a worse prognosis compared to biphasic variety with poorly differentiated being the worst [ 5 ]. The pathological diagnosis of a SS can be challenging with a wide array of differentials including, solitary fibrous tumor, malignant peripheral nerve sheath tumor, clear cell sarcoma, fibrosarcoma and spindle cell rhabdomyosarcoma [ 6 ]. Presence of a prominent ‘staghorn’ vascular pattern may cause confusion in differentiating it from hemangiopericytoma which is a close differential [ 7 ]. Epithelial component of SS is positive for Cytokeratins and TLE1, EMA, BCL2 and negative for CD34, caldesmon, desmin, myogenin, S100, HMB45 and SOX10 [ 2 ]. TLE-1 belongs to wide family of proteins that act on multiple transcription factors and signalling pathways. This is one of the most sensitive markers for SS due to its role in the Wnt/β- catenin pathway in the tumorigenesis of SS [ 8 ]. Although, CD34 is a marker for hematopoietic cell origin and generally negative in SS, poorly differentiated variant may exhibit its positivity [ 7 ]. The gold standard for diagnosis of SS is genetic testing through Fluorescence in situ Hybridization, flow cytometry or RT-PCR to detect translocation t(X;18) which is a gene fusion protein of SS18 and SSX1-2, which is a fusion protein [ 8 ]. Due to the lack of widescale availability of this testing, pathologists often rely on IHC for accurate diagnosis of SS. The Royal Marsden staging system is used for staging of the disease which offers a more simplified and accurate prognostic index than the AJCC system and our patient fell into stage IVA [ 9 ]. Primary treatment of SS consists of surgical resection with enbloc bone resection and lymph node dissection. Radiotherapy is indicated for high-risk cases with aggressive histology, positive surgical margins, lesions > 5cm, recurrent or locally advanced cases [ 10 ]. Chemotherapy with doxorubicin and ifosfamide can be offered in cases of recurrent and metastatic diseases. Even in cases of a large tumor, neoadjuvant chemotherapy may be used to downsize the tumor and reduce surgical morbidity. Due to high chance of local recurrence in the jaw, close and early follow up is mandatory to salvage, foregoing which may result in early mortality. Even with aggressive therapy, long term prognosis remains grim due to the aggressive nature due to development of lung secondaries. 5-year survival is reported around 65–80% with 45% chances of recurrence. Primary synovial sarcoma of the mandible is rare and carries poor prognosis. Preoperative diagnosis is difficult due to non-specificity of clinical and histological features. Final confirmation is possible through immunohistochemistry and genetic testing. Surgical resection is the mainstay of treatment with radiotherapy reserved for aggressive cases. Declarations Funding – This research did not receive any specific grant from any funding agencies in the public, commercial or non-profit sectors. Compliance with Ethical standards – Ethical approval is not required for Case reports and Images from the Institutional Ethics Committee of SMS Medical College, Jaipur. Conflict of interest – The authors declare no conflict of interest Consent to participate – Written informed consent was obtained from the patient for use of clinical information and de-identified photographs. Consent for publication – Written informed consent was obtained from the patient for publication of clinical information and de-identified photographs Data availability – Data will be made available on reasonable request. Code availability – No special software or data code was used for the study as this was a case report and no data analysis was done. Authors Contributions – RC, YP, KKL were responsible for conception and design of the work and data acquisition. RC, YP, PP, SS drafted the work and revised it critically for important intellectual content. All authors approved the version to be published and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. References Tao Q, Qiao B, Wang Y, Hu F. Diagnosis and treatment of primary synovial cell sarcoma that occurred in the left mandible body: A case report and literature review. Oral Surgery, Oral Med Oral Pathol Oral Radiol Endodontology. 2011 Feb 1;111(2):e12–20. Soltaninia O, Dehghan A, Fatehi F, Naderi H. A rare intraosseous synovial sarcoma of the mandible: A case report. Int J Surg Case Rep. 2024 Jul 1;120:109880. Desai S, Pol J, Patil D, Hormuzdi D, Shinde R, Goyal P, et al. Synovial sarcoma of the oral cavity: Report of 4 cases and review of the literature. Rom J Rhinol. 2023 Jul 1;13(51):111–21. Quan H, Sreekissoon S, Wang Y. Synovial sarcoma of the head and neck: A review of reported cases on the clinical characteristics and treatment methods. Front Cell Dev Biol. 2023 Jan 6;10:1077756. Khalili M, Eshghyar N, Ensani F, Shakib PA. Synovial sarcoma of the mandible. J Res Med Sci. 2012 Nov;17(11):1082. Donohoe E, Barry T, Martin D, Tietz B. Case report: monophasic synovial sarcoma of the mandible. Oral Surg Oral Med Oral Pathol Oral Radiol. 2021 Jul 1;132(1):e16. Koga C, Harada H, Kusukawa J, Kameyama T. Synovial sarcoma arising in the mandibular bone. Oral Oncol Extra. 2005 Mar 1;41(3):45–8. Teixeira LN, Zambaldi Da Cruz E, Cláudia A, Rosa G, Rodrigues AA, Passador-Santos F, et al. Primary Intraosseous Synovial Sarcoma in the Mandible. Case Rep Oncol Med. 2021 Jan 1;2021(1):9945591. Ramanathan RC, A’Hern R, Fisher C, Thomas JM. Modified staging system for extremity soft tissue sarcomas. Ann Surg Oncol. 1999 Jan;6(1):57–69. Liu Z, Jin S, Fu S, Hu Y, He Y. Management of the primary intraosseous synovial sarcoma of the jaws: Be careful of the surgical margin. J Oral Maxillofac Surg. 2015 Mar 1;73(3):550–63. Additional Declarations No competing interests reported. Supplementary Files CAREchecklistEnglish.pdf Cite Share Download PDF Status: Published Journal Publication published 29 Nov, 2025 Read the published version in SN Comprehensive Clinical Medicine → Version 1 posted Editorial decision: Revision requested 02 Sep, 2025 Reviews received at journal 21 Aug, 2025 Reviews received at journal 20 Aug, 2025 Reviews received at journal 18 Aug, 2025 Reviewers agreed at journal 17 Aug, 2025 Reviewers agreed at journal 16 Aug, 2025 Reviews received at journal 14 Aug, 2025 Reviewers agreed at journal 14 Aug, 2025 Reviewers agreed at journal 14 Aug, 2025 Reviewers agreed at journal 13 Aug, 2025 Reviewers invited by journal 12 Aug, 2025 Editor assigned by journal 28 Jul, 2025 Submission checks completed at journal 28 Jul, 2025 First submitted to journal 17 Jul, 2025 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-7151019","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":502160560,"identity":"d76ecd0c-0a13-4550-a6fd-527b036344ad","order_by":0,"name":"Rajat 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discharge\u003c/p\u003e","description":"","filename":"Fig.1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7151019/v1/b8a8efff6c70885f52eb0f6f.jpg"},{"id":89462071,"identity":"d211cd5a-6cc8-4c1e-9b2e-c845e69e06c7","added_by":"auto","created_at":"2025-08-20 08:06:33","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":920721,"visible":true,"origin":"","legend":"\u003cp\u003eContrast enhanced CT showing ill-defined heterogenous soft tissue lesion of 52 x 39 mm in the left lower mandible with destruction of the bone and obliteration of the GBS\u003c/p\u003e","description":"","filename":"Fig.2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7151019/v1/d3100354789ec3035ec912c1.jpg"},{"id":89462074,"identity":"39ae67c9-60e1-4c78-b81c-33c804533c1b","added_by":"auto","created_at":"2025-08-20 08:06:33","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":2518412,"visible":true,"origin":"","legend":"\u003cp\u003eLeft mandibular defect pose resection and neck dissection reconstructed with fibular free flap with overlying muscle and skin paddle for mucosal reconstruction\u003c/p\u003e","description":"","filename":"Fig.3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7151019/v1/3f318080ec9db2f364a45e23.jpg"},{"id":89464362,"identity":"6cc514b1-aab2-4d06-9f35-e034c9effefc","added_by":"auto","created_at":"2025-08-20 08:22:33","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":2917778,"visible":true,"origin":"","legend":"\u003cp\u003ePost operative follow up with healed mucosal covering skin and adequate mouth opening\u003c/p\u003e","description":"","filename":"Fig.4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7151019/v1/d4dd23a7b4c4346bde82eb52.jpg"},{"id":97178335,"identity":"a761cb22-88b2-40f0-aa8e-563fee820c32","added_by":"auto","created_at":"2025-12-01 16:08:15","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":34071727,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7151019/v1/22e65006-7329-4c51-a54b-e808c0a8f5ca.pdf"},{"id":89463670,"identity":"38752a9c-ac55-4b75-806b-af4706d794fa","added_by":"auto","created_at":"2025-08-20 08:14:33","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":185296,"visible":true,"origin":"","legend":"","description":"","filename":"CAREchecklistEnglish.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7151019/v1/31c0fe175bca3d4c0c85c251.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eWhen Sarcoma Strikes the Jaw: A Rare Case of Intraosseous Synovial Sarcoma\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eSynovial sarcoma (SS) is a malignant soft tissue tumor of uncertain histogenesis which may present with varied epithelial differentiation. It forms 5–10% of all soft tissue sarcomas and most commonly presents in the extremities [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. It usually occurs in joint capsules and tendinous regions but relation to synovium may not always be present. SS of the head and neck region forms 6–7% of all cases and most common site of synovial sarcoma in the head and neck region is the hypopharynx, parapharyngeal spaces and posterior pharyngeal wall. Due to the pluripotent cell of origin, they can also arise in intraosseous locations, albeit rarely, in the oral cavity but nonetheless carrying worse prognosis [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. We report a rare case of primary synovial sarcoma arising from the mandibular bone treated with surgical resection and adjuvant radiotherapy.\u003c/p\u003e"},{"header":"Case presentation","content":"\u003cp\u003eA 52-year-old gentleman presented to our oncology department with a 6-month history of swelling in the left lower jaw associated with dull pain and loosening of teeth which had recently ulcerated through the skin with mucoid discharge. On local examination, he was found to have a poor dental hygiene with partial loss of dentition and a 6 x 4 cm mass in the left mandibular region with normal overlying mucosa and gingivobuccal sulcus (GBS) and ulceration over the inferior aspect of skin with purulent discharge (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Contrast enhanced Computerized tomography (CECT) revealed an ill-defined heterogenous soft tissue lesion of 52 x 39 mm in the left lower mandible with destruction of the bone and obliteration of the GBS (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Incisional biopsy showed plump spindly cells with hyperchromatic nuclei arranged in haphazard fascicles with a differential of high-grade sarcoma or sarcomatoid variant of squamous cell carcinoma due to the intraoral location of tumor. On immunohistochemistry (IHC), the tumor cells were found to be positive for CK, vimentin, Bcl2 and TLE-1 and negative for P63, P40, caldesmon, SMA, HMB45, S100 and beta-catenin confirming synovial sarcoma. The patient underwent wide local excision of the tumor with enbloc segmental mandibulectomy and supra-omohyoid neck dissection with fibular osteocutaneous free flap reconstruction (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). The surgical histopathology confirmed the biopsy diagnosis with negative margins and one positive lymph node out of 15. The post operative period was uneventful. Due to the high-grade nature of SS, the tumor bed and neck was treated with adjuvant radiotherapy (50.4 Gy in 25 fractions). The patient tolerated the treatment with minimal toxicity. He was found to be disease free with good oral function at 6 months follow up (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e"},{"header":"Discussion and conclusion","content":"\u003cp\u003eSynovial sarcoma (SS) arises from pluripotent mesenchymal cells and is generally considered a high-grade sarcoma. Although 70% of these cases present in the extremities, a good chunk can virtually arise from any tissue and location in the body. SS has been described in various parts of the oral cavity including tongue, palate, maxilla, gingiva and mandible [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Due to the cell of origin being pluripotent mesenchymal cells, intraosseous origin is also possible. Rare sites in the head and neck region such as the temporomandibular joint (TMJ), coronoid process of mandible and occipital bone have been reported in the literature [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Due to its propensity to arise in para-articular regions, SS is infrequent in the mandibular and maxillary bodies as compared to TMJ.\u003c/p\u003e\u003cp\u003eImaging can prove to be unreliable to make an accurate diagnosis, nonetheless, some classical features may cast light on the likelihood of its presence. A panoramic radiograph of the mandible shows a multiocular radiolucent lytic lesion within the body of the mandible with cortical plate expansion. CECT is a better modality to determine the exact extent of tissue and bony involvement. SS can have four histological variants including i) monophasic spindle cell, ii) monophasic epithelioid iii) biphasic and iv) poorly differentiated or ossifying types. Diagnosis is made on biopsy but may prove to be difficult in cases of poorly differentiated and monophasic subtypes whereas the biphasic form may be reliably confirmed. They require IHC and molecular testing for confirmation. The monophasic variant has a worse prognosis compared to biphasic variety with poorly differentiated being the worst [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe pathological diagnosis of a SS can be challenging with a wide array of differentials including, solitary fibrous tumor, malignant peripheral nerve sheath tumor, clear cell sarcoma, fibrosarcoma and spindle cell rhabdomyosarcoma [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Presence of a prominent ‘staghorn’ vascular pattern may cause confusion in differentiating it from hemangiopericytoma which is a close differential [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Epithelial component of SS is positive for Cytokeratins and TLE1, EMA, BCL2 and negative for CD34, caldesmon, desmin, myogenin, S100, HMB45 and SOX10 [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. TLE-1 belongs to wide family of proteins that act on multiple transcription factors and signalling pathways. This is one of the most sensitive markers for SS due to its role in the Wnt/β- catenin pathway in the tumorigenesis of SS [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Although, CD34 is a marker for hematopoietic cell origin and generally negative in SS, poorly differentiated variant may exhibit its positivity [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. The gold standard for diagnosis of SS is genetic testing through Fluorescence in situ Hybridization, flow cytometry or RT-PCR to detect translocation t(X;18) which is a gene fusion protein of SS18 and SSX1-2, which is a fusion protein [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Due to the lack of widescale availability of this testing, pathologists often rely on IHC for accurate diagnosis of SS.\u003c/p\u003e\u003cp\u003eThe Royal Marsden staging system is used for staging of the disease which offers a more simplified and accurate prognostic index than the AJCC system and our patient fell into stage IVA [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Primary treatment of SS consists of surgical resection with enbloc bone resection and lymph node dissection. Radiotherapy is indicated for high-risk cases with aggressive histology, positive surgical margins, lesions \u0026gt; 5cm, recurrent or locally advanced cases [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Chemotherapy with doxorubicin and ifosfamide can be offered in cases of recurrent and metastatic diseases. Even in cases of a large tumor, neoadjuvant chemotherapy may be used to downsize the tumor and reduce surgical morbidity. Due to high chance of local recurrence in the jaw, close and early follow up is mandatory to salvage, foregoing which may result in early mortality. Even with aggressive therapy, long term prognosis remains grim due to the aggressive nature due to development of lung secondaries. 5-year survival is reported around 65–80% with 45% chances of recurrence.\u003c/p\u003e\u003cp\u003ePrimary synovial sarcoma of the mandible is rare and carries poor prognosis. Preoperative diagnosis is difficult due to non-specificity of clinical and histological features. Final confirmation is possible through immunohistochemistry and genetic testing. Surgical resection is the mainstay of treatment with radiotherapy reserved for aggressive cases.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e – This research did not receive any specific grant from any funding agencies in the\u0026nbsp;\u003c/p\u003e\n\u003cp\u003epublic, commercial or non-profit sectors.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompliance with Ethical standards\u003c/strong\u003e – Ethical approval is not required for Case reports and Images from the Institutional Ethics Committee of SMS Medical College, Jaipur.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e – The authors declare no conflict of interest\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to participate\u003c/strong\u003e – Written informed consent was obtained from the patient for use of clinical information and de-identified photographs.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e – Written informed consent was obtained from the patient for publication of clinical information and de-identified photographs\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e – Data will be made available on reasonable request.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCode availability\u003c/strong\u003e – No special software or data code was used for the study as this was a case report and no data analysis was done. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors Contributions\u003c/strong\u003e – RC, YP, KKL were responsible for conception and design of the work and data acquisition. RC, YP, PP, SS drafted the work and revised it critically for important intellectual content. All authors approved the version to be published and agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eTao Q, Qiao B, Wang Y, Hu F. Diagnosis and treatment of primary synovial cell sarcoma that occurred in the left mandible body: A case report and literature review. Oral Surgery, Oral Med Oral Pathol Oral Radiol Endodontology. 2011 Feb 1;111(2):e12\u0026ndash;20. \u003c/li\u003e\n\u003cli\u003eSoltaninia O, Dehghan A, Fatehi F, Naderi H. A rare intraosseous synovial sarcoma of the mandible: A case report. Int J Surg Case Rep. 2024 Jul 1;120:109880. \u003c/li\u003e\n\u003cli\u003eDesai S, Pol J, Patil D, Hormuzdi D, Shinde R, Goyal P, et al. Synovial sarcoma of the oral cavity: Report of 4 cases and review of the literature. Rom J Rhinol. 2023 Jul 1;13(51):111\u0026ndash;21. \u003c/li\u003e\n\u003cli\u003eQuan H, Sreekissoon S, Wang Y. Synovial sarcoma of the head and neck: A review of reported cases on the clinical characteristics and treatment methods. Front Cell Dev Biol. 2023 Jan 6;10:1077756. \u003c/li\u003e\n\u003cli\u003eKhalili M, Eshghyar N, Ensani F, Shakib PA. Synovial sarcoma of the mandible. J Res Med Sci. 2012 Nov;17(11):1082. \u003c/li\u003e\n\u003cli\u003eDonohoe E, Barry T, Martin D, Tietz B. Case report: monophasic synovial sarcoma of the mandible. Oral Surg Oral Med Oral Pathol Oral Radiol. 2021 Jul 1;132(1):e16. \u003c/li\u003e\n\u003cli\u003eKoga C, Harada H, Kusukawa J, Kameyama T. Synovial sarcoma arising in the mandibular bone. Oral Oncol Extra. 2005 Mar 1;41(3):45\u0026ndash;8. \u003c/li\u003e\n\u003cli\u003eTeixeira LN, Zambaldi Da Cruz E, Cl\u0026aacute;udia A, Rosa G, Rodrigues AA, Passador-Santos F, et al. Primary Intraosseous Synovial Sarcoma in the Mandible. Case Rep Oncol Med. 2021 Jan 1;2021(1):9945591. \u003c/li\u003e\n\u003cli\u003eRamanathan RC, A\u0026rsquo;Hern R, Fisher C, Thomas JM. Modified staging system for extremity soft tissue sarcomas. Ann Surg Oncol. 1999 Jan;6(1):57\u0026ndash;69. \u003c/li\u003e\n\u003cli\u003eLiu Z, Jin S, Fu S, Hu Y, He Y. Management of the primary intraosseous synovial sarcoma of the jaws: Be careful of the surgical margin. J Oral Maxillofac Surg. 2015 Mar 1;73(3):550\u0026ndash;63. \u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"sn-comprehensive-clinical-medicine","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sncm","sideBox":"Learn more about [SN Comprehensive Clinical Medicine](https://www.springer.com/journal/42399)","snPcode":"42399","submissionUrl":"https://submission.nature.com/new-submission/42399/3","title":"SN Comprehensive Clinical Medicine","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Synovial sarcoma, intraosseous sarcoma, jaw tumors, synovial sarcoma of jaw","lastPublishedDoi":"10.21203/rs.3.rs-7151019/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7151019/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eIntroduction\u003c/h2\u003e\u003cp\u003eSynovial sarcoma (SS) is a malignant soft tissue tumor of uncertain histogenesis which forms 5\u0026ndash;10% of all soft tissue sarcomas and most commonly presents in the extremities. SS of the head and neck region forms 6\u0026ndash;7% of all cases and most common site is the hypopharynx, parapharyngeal spaces and posterior pharyngeal wall. We report a rare case of primary synovial sarcoma arising from the mandibular bone treated with surgical resection and adjuvant radiotherapy.\u003c/p\u003e\u003ch2\u003eCase presentation\u003c/h2\u003e\u003cp\u003eA 52-year-old gentleman presented with a 6-month history of swelling in the left lower jaw associated with dull pain and loosening of teeth which, on examination, was revealed to be a 6 x 4 cm mass in the left mandibular region. CECT revealed an ill-defined heterogenous soft tissue lesion of 52 x 39 mm in the left lower mandible with destruction of the bone. Incisional biopsy showed plump spindly cells positive for CK, vimentin, Bcl2 and TLE-1 and negative for P63, P40, caldesmon, SMA, HMB45, S100 and beta-catenin confirming synovial sarcoma. The patient underwent wide local excision of the tumor with enbloc segmental mandibulectomy and supra-omohyoid neck dissection with fibular osteocutaneous free flap reconstruction. Due to the high-grade nature of SS, the tumor bed and neck was treated with adjuvant radiotherapy (50.4 Gy in 25 fractions).\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003ePrimary synovial sarcoma of the mandible is rare and carries poor prognosis. Histological confirmation is possible through immunohistochemistry and genetic testing. Surgical resection is the mainstay of treatment with radiotherapy reserved for aggressive cases\u003c/p\u003e","manuscriptTitle":"When Sarcoma Strikes the Jaw: A Rare Case of Intraosseous Synovial Sarcoma","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-20 08:06:28","doi":"10.21203/rs.3.rs-7151019/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-09-02T17:48:55+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-21T13:08:22+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-20T15:39:51+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-18T19:26:00+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"36004409621004703385161110293049696987","date":"2025-08-17T14:29:02+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"273442657247496085450585856527702760405","date":"2025-08-16T12:23:06+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-14T11:02:06+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"330189840372931960031913901183556729557","date":"2025-08-14T09:23:26+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"158562139697809288762147595199456972917","date":"2025-08-14T09:03:59+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"128946394974871469738458062936366167545","date":"2025-08-13T14:18:16+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-12T08:05:35+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-28T15:53:50+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-28T12:46:39+00:00","index":"","fulltext":""},{"type":"submitted","content":"SN Comprehensive Clinical Medicine","date":"2025-07-17T16:15:12+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"sn-comprehensive-clinical-medicine","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sncm","sideBox":"Learn more about [SN Comprehensive Clinical Medicine](https://www.springer.com/journal/42399)","snPcode":"42399","submissionUrl":"https://submission.nature.com/new-submission/42399/3","title":"SN Comprehensive Clinical Medicine","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"1b9a26af-096b-476a-bce3-a5e93911f7d4","owner":[],"postedDate":"August 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-01T16:00:50+00:00","versionOfRecord":{"articleIdentity":"rs-7151019","link":"https://doi.org/10.1007/s42399-025-02146-1","journal":{"identity":"sn-comprehensive-clinical-medicine","isVorOnly":false,"title":"SN Comprehensive Clinical Medicine"},"publishedOn":"2025-11-29 15:57:21","publishedOnDateReadable":"November 29th, 2025"},"versionCreatedAt":"2025-08-20 08:06:28","video":"","vorDoi":"10.1007/s42399-025-02146-1","vorDoiUrl":"https://doi.org/10.1007/s42399-025-02146-1","workflowStages":[]},"version":"v1","identity":"rs-7151019","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7151019","identity":"rs-7151019","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}