Squamous cell carcinoma arising within a mature cystic teratoma of the ovary in a postmenopausal woman: A case report and literature review

Squamous cell carcinoma arising within a mature cystic teratoma of the ovary in a postmenopausal woman: A case report and literature review | 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 Squamous cell carcinoma arising within a mature cystic teratoma of the ovary in a postmenopausal woman: A case report and literature review Vishal Bahall, Visham Bhagaloo, Lance De Barry, Nadia Nidhan, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8575529/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: Malignant transformation of mature cystic teratomas (MCTs) of the ovary is rare, with squamous cell carcinoma (SCC) being the most common histologic subtype. Due to its nonspecific clinical presentation and similarity to benign dermoid cysts, preoperative diagnosis is often challenging, resulting in delayed recognition and poorer outcomes. Risk factors such as postmenopausal status, large tumour size, and elevated tumour markers should serve as red flags prompting clinical suspicion for malignant transformation within an ovarian teratoma. Case presentation: We describe the case of a 52-year-old woman who presented with chronic abdominal distension, bloating, and early satiety. Imaging revealed large bilateral dermoid cysts with associated right-sided hydroureteronephrosis and an elevated CA-125 level. She underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy, omentectomy, appendectomy and peritoneal washings. Histopathology confirmed a moderately differentiated squamous cell carcinoma arising within a mature cystic teratoma, confined to the right ovary (pT1a). Conclusion: Squamous cell carcinoma arising in a mature cystic teratoma represents a rare but clinically significant form of malignant transformation. This case underscores the importance of considering malignancy in postmenopausal women with large or symptomatic ovarian dermoid cysts and highlights the role of comprehensive histopathological evaluation in establishing an accurate diagnosis and guiding optimal management. squamous cell carcinoma mature cystic teratoma ovarian malignancy malignant transformation ovarian germ cell tumour Figures Figure 1 Figure 2 Introduction Mature cystic teratoma of the ovary (MCTO), also known as a dermoid cyst, is a benign germ cell neoplasm composed of well-differentiated tissues derived from all three germ layers. It represents approximately 60% of all benign ovarian tumours and is among the most frequently encountered ovarian neoplasms in women of reproductive age. The precise aetiology and pathophysiology of MCTO remain unclear, but hormonal, genetic, and microenvironmental factors are thought to play contributory roles. Malignant transformation within an MCTO is rare, occurring in approximately 1–2% of cases (1). It is most frequently reported in women aged 40–55 years, roughly a decade older than those typically affected by benign lesions (2). Squamous cell carcinoma (SCC) is the predominant histologic subtype, accounting for 80–89% of all malignancies arising from dermoid tumours (3). SCC transformation is more commonly observed in postmenopausal women and is often associated with large tumour size, elevated serum tumour markers (CA-125, CA19-9, CEA), and solid areas on imaging (4). Preoperative diagnosis remains challenging, as clinical and radiological features of benign and malignant MCTOs often overlap. Patients are frequently diagnosed incidentally or at advanced stages, leading to poorer outcomes (4, 5). Despite the absence of standardized treatment protocols, surgical staging remains the cornerstone of management, supplemented by adjuvant chemotherapy in cases demonstrating high-risk or advanced disease features (5). Herein, we report the case of a 52-year-old woman with a moderately differentiated squamous cell carcinoma arising within a mature cystic teratoma of the right ovary, confined to the ovary (pT1a). This case underscores the diagnostic challenges posed by malignant transformation of MCTO and highlights the importance of maintaining a high index of suspicion in older women presenting with large or symptomatic dermoid cysts and elevated tumour markers. Case Presentation A 52-year-old multiparous woman presented with a one-year history of progressive abdominal distension and a one-month history of new-onset lower abdominal pain. This was associated with intermenstrual bleeding, early satiety, and abdominal bloating. She had no known medical comorbidities and her surgical history was significant for two prior lower segment caesarean sections. There was no reported personal or family history of gynecologic malignancy. On clinical examination, the abdomen was markedly distended with a mildly tender, firm mass equivalent to a 40-week gestation, arising from the pelvis. Speculum examination revealed a grossly normal cervix measuring approximately 2 cm, deviated to the left. Bimanual examination confirmed a large pelvic–abdominal mass with limited mobility. Baseline laboratory investigations demonstrated a haemoglobin level of 13.1 g/dL, with preserved renal function. Tumor marker evaluation revealed an elevated cancer antigen 125 (CA-125) level of 111.3 U/mL and a lactate dehydrogenase (LDH) level of 183 U/L. Contrast-enhanced computed tomography (CT) of the chest, abdomen, and pelvis demonstrated no intrathoracic pathology. In the pelvis, a large predominantly cystic mass measuring 23.1 cm × 17.3 cm × 18.7 cm was identified arising from the right hemipelvis (Fig. 1 ). In addition, a left adnexal complex mass measuring 11.7 cm × 6.6 cm × 12.6 cm with imaging characteristics suggestive of a mature cystic teratoma was noted. There was associated mild right-sided hydroureteronephrosis secondary to distal ureteric compression, as well as a fibroid uterus. No radiologic evidence of ascites, lymphadenopathy, or distant metastatic disease was identified. Following multidisciplinary team (MDT) discussion, the patient was counseled regarding the high suspicion for ovarian malignancy. A decision was made to proceed with primary surgical management. She subsequently underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy, infracolic omentectomy, appendectomy, and peritoneal washings. Histopathological examination revealed a markedly enlarged right ovary measuring 33.5 × 22 × 20.5 cm, containing atypical squamous epithelial cells with marked nuclear pleomorphism, hyperchromasia and increased mitotic activity (Fig. 2 A). Tumour islands displayed prominent keratin pearl formation that confirmed squamous differentiation and background benign teratomatous elements that included mature ectodermal tissue (Fig. 2 B, 2 C). This confirmed moderately differentiated squamous cell carcinoma arising within a mature cystic teratoma. The malignancy was confined to the right ovary, with an intact capsule and no surface involvement, consistent with FIGO stage IA disease (pT1a). The left ovary measured 12 × 11 × 7.8 cm and demonstrated features of a benign mature cystic teratoma. Peritoneal washings were negative for malignant cells, and there was no evidence of tumor involvement in the omentum or appendix. In view of the early-stage disease, complete surgical staging, and favorable histopathologic findings, adjuvant therapy was not recommended following MDT review. The patient is currently undergoing surveillance. Discussion Squamous cell carcinoma (SCC) arising within a mature cystic teratoma (MCT) is an uncommon but clinically significant malignancy, accounting for approximately 0.17%- 2% of all MCTs and demonstrates a strong association with increasing patient age (1–3). Most cases are diagnosed in peri- or postmenopausal women, with mean age at diagnosis reported between 50–60 years, nearly two decades later than benign MCTs (1–4). A large systematic review by Li et al reported a mean age of 53.5 years and highlighted that 72% of affected women were more than or equal to 45 years old (1). This demographic pattern suggests a prolonged latency period and supports the hypothesis that malignant transformation represents the culmination of slow growing genomic alterations within long standing MCTs. The exact pathophysiological drivers behind malignant transformation in mature cystic teratomas remain incompletely understood. Proposed mechanisms include the effects of long-standing chronic inflammation, cumulative genomic instability, and the stepwise acquisition of somatic alterations involving key oncogenic and tumour suppressor pathways, particularly T53, PIK3CA, and PTEN (5–7). Age related genomic alterations may further contribute to this evolution, consistent with the long-standing nature of many MCTs prior to diagnosis as mentioned earlier. Additionally, some studies have suggested that high risk human papilloma virus infection may play a contributory role in a subset of cases raising the possibility of viral-mediated oncogenesis in this rare entity (8–10). Several clinical and radiological features have been reported as markers for increased malignant potential. Advanced age (> 50 years), large tumour diameter (> 10cm), elevated serum tumour markers (CA125, CA 19 − 9, CEA, and SCC antigen), and the presence of robust solid components or mural nodules on imaging should raise suspicions (3,10). Hackethal et al’s systematic review of 277 cases demonstrates that 79% of women with SCC-transformed MCTs were postmenopausal, and tumour sizes frequently exceeded 10cm (3). These red flag features were present in our patient, who was 52 years of age, symptomatic, and had significantly enlarged bilateral ovarian masses with associated tumour marker elevation. Despite these features, preoperative diagnosis is challenging due to overlapping clinical presentations between benign and malignant dermoid cysts. Patients commonly present with abdominal distension, pelvic pain, or pressure symptoms related to mass effect. Hydroureteronephrosis in this case highlights the degree of local compression, which may occur even in the absence of advanced malignant spread. Imaging modalities such as CT and MRI can offer diagnostic clues- irregular solid areas, papillary projections, or evidence of invasion- but are not pathognomic (1,3,11). Li et al similarly noted the limitations of imaging and serum markers, compounded by heterogenous reporting across studies (1). Consequently, histopathological evaluation remains the diagnostic gold standard given the absence of a consistent, reliable set of radiological or serum based criteria. Histologically, SCC arising within an MCT demonstrates areas of dysplastic or invasive squamous epithelium within a background of mature teratomatous tissue. Grossly the tumour appears as large and cystic with significant solid components. Focal tearing, localised rupture and penetration of the capsule typically leads to the deposition of keratin debris and formation of keratinous nodules in the peritoneal cavity or adjacent organs (12). Therefore, the most common route of spread is direct extension to adjacent pelvic organs, followed by peritoneal dissemination; lymphatic involvement is less common but increasingly recognised in advanced disease stages (1,12). Regarding the stage at diagnosis, Li et al reported stages I, II, II, IV disease in 50%, 18.8%, 26.8%, and 4.4% of cases respectively, with markedly reduced survival for stages III-IV having worse prognosis compared to stage I in a significant way (1). The overall survival at five years were 85.8%, 39.1%, 26.2% and 0% across stages I-IV respectively (1). Given the rarity of this entity, standardized treatment guidelines do not exist. Management strategies therefore parallel those used for epithelial ovarian carcinoma. Primary cytoreductive surgery remains the cornerstone of therapy and should include total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, peritoneal cytology and in selected cases- lymphadenectomy (3,13). It was found that in SCC of MCT, hysterectomy and omentectomy appear to improve the prognosis (1). In a retrospective case series by Powell et al., all patients presented with stage III-IV disease and had poor outcomes, with a median overall survival of 12.5 months despite radical surgery and platinum-based chemotherapy (14). Their findings demonstrate the aggressive behaviour of advanced SCC in MCT and highlights the importance of early detection. Adjuvant chemotherapy is generally recommended for stage 1C or higher disease, or when high-risk histological features are present. Platinum- based regimens, particularly carboplatin combined with paclitaxel, are widely used and yield the most favourable responses reported to date (1,3,14,15). The role of radiotherapy remains controversial; while some authors propose a potential benefit in isolated pelvic disease, evidence is limited and inconsistent (1,16). For completely excised stage IA disease without capsular breach- as in this case- there is no consensus, and careful surveillance may be appropriate. Early-stage diagnosis, comprehensive staging, and complete resection are the strongest predictors of long- term survival. The patient described in this report benefitted from the tumour being confined to the ovary, thorough staging surgery, and absence of high-risk features, all of which support a favourable prognosis. This case reinforces the need for heightened clinical vigilance in postmenopausal women presenting with large or symptomatic dermoid cysts, particularly when tumour markers are elevated. Abbreviations MCT Mature cystic teratoma MCTO Mature cystic teratoma of the ovary SCC squamous cell carcinoma CA 125–Cancer antigen 125 CA 19–9–Cancer antigen 19 − 9 CEA Carcinoembryonic antigen LDH Lactate dehydrogenase CT Computed tomography MRI Magnetic resonance imaging MDT Multidisciplinary team FIGO International Federation of Gynaecology and Obstetrics Declarations Ethics approval and consent to participate: Not applicable. Consent : Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor of this journal. Availability of data and materials: Not applicable. Competing interests: The authors declare that they have no competing interests. Funding: Not applicable. Authors contributions: VB conceptualized, drafted, and supervised the manuscript. VB, LDB, NN, and SH drafted and edited the manuscript. AR performed the histopathological examination, provided interpretation of the histopathology findings and edited the manuscript. All authors read and approved the final manuscript. Acknowledgements: Not applicable. Authors’ information: VB: Obstetrics and Gynaecology, San Fernando General Hospital, South-West Regional Health Authority VB: Medical Oncology, San Fernando General Hospital, South-West Regional Health Authority, Trinidad and Tobago LDB: Obstetrics and Gynaecology, San Fernando General Hospital, South-West Regional Health Authority NN: Obstetrics and Gynaecology, San Fernando General Hospital, South-West Regional Health Authority SH: Obstetrics and Gynaecology, San Fernando General Hospital, South-West Regional Health Authority AR: Department of Pathology, San Fernando General Hospital, South-West Regional Health Authority, Trinidad and Tobago References Li C, Zhang Q, Zhang S, Dong R, Sun C, Qiu C, et al. Squamous cell carcinoma arising in ovarian mature cystic teratoma: a systematic review. Gynecol Oncol. 2019;154(3):598–604. Dos Santos L, Mok E, Iasonos A, Park KJ, Soslow RA, Aghajanian C, et al. Squamous cell carcinoma arising in mature cystic teratoma of the ovary: A case series and review of the literature. Gynecol Oncol. 2007;105(2):321–4. Hackethal A, Brueggmann D, Bohlmann MK, Franke FE, Tinneberg HR, Münstedt K. Squamous-cell carcinoma in mature cystic teratoma of the ovary: systematic review and analysis of published data. Lancet Oncol. 2008;9(12):1173–80. Koonings PP, Campbell K, Mishell DR Jr, Grimes DA. Relative frequency of primary ovarian neoplasms: a 10-year review. Obstet Gynecol. 1989;74:921–6. Yoshida Y, Kato N, Koshiyama M, et al. Molecular genetic analysis of ovarian squamous cell carcinoma arising from mature cystic teratoma. Int J Gynecol Pathol. 2000;19:354–7. Ulker V, Numanoglu C, et al. The role of p53 in malignant transformation of ovarian dermoid cysts. Eur J Gynaecol Oncol. 2014;35:306–12. O’Neill CJ, McCluggage WG. Morphological and immunohistochemical typing of ovarian cancer. Histopathology. 2011;58(4):539–58. Tseng CJ, Chou HH, Huang KG, et al. Squamous cell carcinoma arising in mature cystic teratoma of the ovary. Gynecol Oncol. 1996;63:364–70. Sato N, Kurman RJ, et al. Detection of HPV DNA in ovarian squamous cell carcinoma arising from MCT. Int J Gynecol Pathol. 1991;10:119–28. Chiang AJ, Chen DR, Cheng JT, Chang TH. Detection of human papilloma virus in squamous cell carcinoma arising from dermoid cysts. Taiwan J Obstet Gynaecol. 2015;54(5):559–66. Kikkawa F, Ishikawa H, et al. Clinical characteristics of malignant transformation of ovarian mature cystic teratoma. Obstet Gynecol. 1997;89:197–202. Kido A, Togashi K, et al. MRI findings in dermoid cysts with malignant transformation. AJR Am J Roentgenol. 1999;172:445–9. Park CH, Kim JY, et al. Surgical outcomes in malignant transformation of MCT. J Obstet Gynaecol Res. 2010;36:789–95. Powell JL, Dulaney DP, Yates WA, et al. Malignant transformation of MCT: clinical characteristics and management. J Reprod Med. 1998;43:1007–11. Kumar A, Schneider V. Chemotherapy for squamous carcinoma arising in dermoid cysts. Cancer. 1983;51:2316–9. Sumi T, Ishiko O. Role of radiotherapy in malignant transformation of ovarian dermoid cysts. Int J Clin Oncol. 2001;6:341–4. 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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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-8575529","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":577703344,"identity":"0a8285e3-0830-480c-924e-5827470efeb8","order_by":0,"name":"Vishal Bahall","email":"","orcid":"","institution":"San Fernando General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Vishal","middleName":"","lastName":"Bahall","suffix":""},{"id":577703345,"identity":"52ec3c7b-7fcb-4992-a153-9ec853cb1ebd","order_by":1,"name":"Visham Bhagaloo","email":"","orcid":"","institution":"San Fernando General 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07:06:10","extension":"xml","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":42030,"visible":true,"origin":"","legend":"","description":"","filename":"1271408af7284e3a9ab41625b5dd4ba11structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8575529/v1/95d47f1a96db59814e8303f2.xml"},{"id":100856480,"identity":"9ce90419-7796-4c12-9872-cba22768870c","added_by":"auto","created_at":"2026-01-22 07:06:10","extension":"html","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":50883,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8575529/v1/d5435861cf70c3848483c0a4.html"},{"id":100856474,"identity":"168c0ce2-40c6-4ddc-900d-a008274f8421","added_by":"auto","created_at":"2026-01-22 07:06:10","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":40179,"visible":true,"origin":"","legend":"Abdominopelvic CT image demonstrates a large cystic mass with solid components measuring 23.1 cm x 17.3 cm x 18.7 cm.","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8575529/v1/279f77966bb3644a6a4ed1b3.jpeg"},{"id":100859337,"identity":"b7b60732-acca-41fc-bf43-b72137867437","added_by":"auto","created_at":"2026-01-22 07:26:51","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2371737,"visible":true,"origin":"","legend":"Histopathological features of the tumour. Tumour nests are composed of atypical squamous epithelial cells demonstrating marked nuclear pleomorphism, hyperchromasia, and increased mitotic activity (A, arrow). Prominent keratin pearl formation is seen within tumour islands, confirming squamous differentiation (B, arrowhead). The background shows benign teratomatous components, including mature ectodermal tissue (C).","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8575529/v1/3e53046445bb7f45afe6f1d3.png"},{"id":102294789,"identity":"123f4685-c88e-49be-b522-f3d4f4bcecb3","added_by":"auto","created_at":"2026-02-10 09:57:18","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3142007,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8575529/v1/d5a68ee9-d7c5-4db9-b137-aa554c89d35d.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Squamous cell carcinoma arising within a mature cystic teratoma of the ovary in a postmenopausal woman: A case report and literature review","fulltext":[{"header":"Introduction","content":"\u003cp\u003eMature cystic teratoma of the ovary (MCTO), also known as a dermoid cyst, is a benign germ cell neoplasm composed of well-differentiated tissues derived from all three germ layers. It represents approximately 60% of all benign ovarian tumours and is among the most frequently encountered ovarian neoplasms in women of reproductive age. The precise aetiology and pathophysiology of MCTO remain unclear, but hormonal, genetic, and microenvironmental factors are thought to play contributory roles.\u003c/p\u003e \u003cp\u003eMalignant transformation within an MCTO is rare, occurring in approximately 1\u0026ndash;2% of cases (1). It is most frequently reported in women aged 40\u0026ndash;55 years, roughly a decade older than those typically affected by benign lesions (2). Squamous cell carcinoma (SCC) is the predominant histologic subtype, accounting for 80\u0026ndash;89% of all malignancies arising from dermoid tumours (3). SCC transformation is more commonly observed in postmenopausal women and is often associated with large tumour size, elevated serum tumour markers (CA-125, CA19-9, CEA), and solid areas on imaging (4).\u003c/p\u003e \u003cp\u003ePreoperative diagnosis remains challenging, as clinical and radiological features of benign and malignant MCTOs often overlap. Patients are frequently diagnosed incidentally or at advanced stages, leading to poorer outcomes (4, 5). Despite the absence of standardized treatment protocols, surgical staging remains the cornerstone of management, supplemented by adjuvant chemotherapy in cases demonstrating high-risk or advanced disease features (5).\u003c/p\u003e \u003cp\u003eHerein, we report the case of a 52-year-old woman with a moderately differentiated squamous cell carcinoma arising within a mature cystic teratoma of the right ovary, confined to the ovary (pT1a). This case underscores the diagnostic challenges posed by malignant transformation of MCTO and highlights the importance of maintaining a high index of suspicion in older women presenting with large or symptomatic dermoid cysts and elevated tumour markers.\u003c/p\u003e"},{"header":"Case Presentation","content":"\u003cp\u003eA 52-year-old multiparous woman presented with a one-year history of progressive abdominal distension and a one-month history of new-onset lower abdominal pain. This was associated with intermenstrual bleeding, early satiety, and abdominal bloating. She had no known medical comorbidities and her surgical history was significant for two prior lower segment caesarean sections. There was no reported personal or family history of gynecologic malignancy.\u003c/p\u003e \u003cp\u003eOn clinical examination, the abdomen was markedly distended with a mildly tender, firm mass equivalent to a 40-week gestation, arising from the pelvis. Speculum examination revealed a grossly normal cervix measuring approximately 2 cm, deviated to the left. Bimanual examination confirmed a large pelvic\u0026ndash;abdominal mass with limited mobility.\u003c/p\u003e \u003cp\u003eBaseline laboratory investigations demonstrated a haemoglobin level of 13.1 g/dL, with preserved renal function. Tumor marker evaluation revealed an elevated cancer antigen 125 (CA-125) level of 111.3 U/mL and a lactate dehydrogenase (LDH) level of 183 U/L.\u003c/p\u003e \u003cp\u003eContrast-enhanced computed tomography (CT) of the chest, abdomen, and pelvis demonstrated no intrathoracic pathology. In the pelvis, a large predominantly cystic mass measuring 23.1 cm \u0026times; 17.3 cm \u0026times; 18.7 cm was identified arising from the right hemipelvis (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). In addition, a left adnexal complex mass measuring 11.7 cm \u0026times; 6.6 cm \u0026times; 12.6 cm with imaging characteristics suggestive of a mature cystic teratoma was noted. There was associated mild right-sided hydroureteronephrosis secondary to distal ureteric compression, as well as a fibroid uterus. No radiologic evidence of ascites, lymphadenopathy, or distant metastatic disease was identified.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFollowing multidisciplinary team (MDT) discussion, the patient was counseled regarding the high suspicion for ovarian malignancy. A decision was made to proceed with primary surgical management. She subsequently underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy, infracolic omentectomy, appendectomy, and peritoneal washings.\u003c/p\u003e \u003cp\u003eHistopathological examination revealed a markedly enlarged right ovary measuring 33.5 \u0026times; 22 \u0026times; 20.5 cm, containing atypical squamous epithelial cells with marked nuclear pleomorphism, hyperchromasia and increased mitotic activity (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eA). Tumour islands displayed prominent keratin pearl formation that confirmed squamous differentiation and background benign teratomatous elements that included mature ectodermal tissue (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eB, \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003eC). This confirmed moderately differentiated squamous cell carcinoma arising within a mature cystic teratoma. The malignancy was confined to the right ovary, with an intact capsule and no surface involvement, consistent with FIGO stage IA disease (pT1a). The left ovary measured 12 \u0026times; 11 \u0026times; 7.8 cm and demonstrated features of a benign mature cystic teratoma. Peritoneal washings were negative for malignant cells, and there was no evidence of tumor involvement in the omentum or appendix.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn view of the early-stage disease, complete surgical staging, and favorable histopathologic findings, adjuvant therapy was not recommended following MDT review. The patient is currently undergoing surveillance.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eSquamous cell carcinoma (SCC) arising within a mature cystic teratoma (MCT) is an uncommon but clinically significant malignancy, accounting for approximately 0.17%- 2% of all MCTs and demonstrates a strong association with increasing patient age (1\u0026ndash;3). Most cases are diagnosed in peri- or postmenopausal women, with mean age at diagnosis reported between 50\u0026ndash;60 years, nearly two decades later than benign MCTs (1\u0026ndash;4). A large systematic review by Li et al reported a mean age of 53.5 years and highlighted that 72% of affected women were more than or equal to 45 years old (1). This demographic pattern suggests a prolonged latency period and supports the hypothesis that malignant transformation represents the culmination of slow growing genomic alterations within long standing MCTs.\u003c/p\u003e \u003cp\u003eThe exact pathophysiological drivers behind malignant transformation in mature cystic teratomas remain incompletely understood. Proposed mechanisms include the effects of long-standing chronic inflammation, cumulative genomic instability, and the stepwise acquisition of somatic alterations involving key oncogenic and tumour suppressor pathways, particularly T53, PIK3CA, and PTEN (5\u0026ndash;7). Age related genomic alterations may further contribute to this evolution, consistent with the long-standing nature of many MCTs prior to diagnosis as mentioned earlier. Additionally, some studies have suggested that high risk human papilloma virus infection may play a contributory role in a subset of cases raising the possibility of viral-mediated oncogenesis in this rare entity (8\u0026ndash;10).\u003c/p\u003e \u003cp\u003eSeveral clinical and radiological features have been reported as markers for increased malignant potential. Advanced age (\u0026gt;\u0026thinsp;50 years), large tumour diameter (\u0026gt;\u0026thinsp;10cm), elevated serum tumour markers (CA125, CA 19\u0026thinsp;\u0026minus;\u0026thinsp;9, CEA, and SCC antigen), and the presence of robust solid components or mural nodules on imaging should raise suspicions (3,10). Hackethal et al\u0026rsquo;s systematic review of 277 cases demonstrates that 79% of women with SCC-transformed MCTs were postmenopausal, and tumour sizes frequently exceeded 10cm (3). These red flag features were present in our patient, who was 52 years of age, symptomatic, and had significantly enlarged bilateral ovarian masses with associated tumour marker elevation.\u003c/p\u003e \u003cp\u003eDespite these features, preoperative diagnosis is challenging due to overlapping clinical presentations between benign and malignant dermoid cysts. Patients commonly present with abdominal distension, pelvic pain, or pressure symptoms related to mass effect. Hydroureteronephrosis in this case highlights the degree of local compression, which may occur even in the absence of advanced malignant spread. Imaging modalities such as CT and MRI can offer diagnostic clues- irregular solid areas, papillary projections, or evidence of invasion- but are not pathognomic (1,3,11). Li et al similarly noted the limitations of imaging and serum markers, compounded by heterogenous reporting across studies (1). Consequently, histopathological evaluation remains the diagnostic gold standard given the absence of a consistent, reliable set of radiological or serum based criteria.\u003c/p\u003e \u003cp\u003eHistologically, SCC arising within an MCT demonstrates areas of dysplastic or invasive squamous epithelium within a background of mature teratomatous tissue. Grossly the tumour appears as large and cystic with significant solid components. Focal tearing, localised rupture and penetration of the capsule typically leads to the deposition of keratin debris and formation of keratinous nodules in the peritoneal cavity or adjacent organs (12). Therefore, the most common route of spread is direct extension to adjacent pelvic organs, followed by peritoneal dissemination; lymphatic involvement is less common but increasingly recognised in advanced disease stages (1,12).\u003c/p\u003e \u003cp\u003eRegarding the stage at diagnosis, Li et al reported stages I, II, II, IV disease in 50%, 18.8%, 26.8%, and 4.4% of cases respectively, with markedly reduced survival for stages III-IV having worse prognosis compared to stage I in a significant way (1). The overall survival at five years were 85.8%, 39.1%, 26.2% and 0% across stages I-IV respectively (1).\u003c/p\u003e \u003cp\u003eGiven the rarity of this entity, standardized treatment guidelines do not exist. Management strategies therefore parallel those used for epithelial ovarian carcinoma. Primary cytoreductive surgery remains the cornerstone of therapy and should include total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, peritoneal cytology and in selected cases- lymphadenectomy (3,13). It was found that in SCC of MCT, hysterectomy and omentectomy appear to improve the prognosis (1). In a retrospective case series by Powell et al., all patients presented with stage III-IV disease and had poor outcomes, with a median overall survival of 12.5 months despite radical surgery and platinum-based chemotherapy (14). Their findings demonstrate the aggressive behaviour of advanced SCC in MCT and highlights the importance of early detection.\u003c/p\u003e \u003cp\u003eAdjuvant chemotherapy is generally recommended for stage 1C or higher disease, or when high-risk histological features are present. Platinum- based regimens, particularly carboplatin combined with paclitaxel, are widely used and yield the most favourable responses reported to date (1,3,14,15). The role of radiotherapy remains controversial; while some authors propose a potential benefit in isolated pelvic disease, evidence is limited and inconsistent (1,16). For completely excised stage IA disease without capsular breach- as in this case- there is no consensus, and careful surveillance may be appropriate.\u003c/p\u003e \u003cp\u003eEarly-stage diagnosis, comprehensive staging, and complete resection are the strongest predictors of long- term survival. The patient described in this report benefitted from the tumour being confined to the ovary, thorough staging surgery, and absence of high-risk features, all of which support a favourable prognosis. This case reinforces the need for heightened clinical vigilance in postmenopausal women presenting with large or symptomatic dermoid cysts, particularly when tumour markers are elevated.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eMCT\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eMature cystic teratoma\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eMCTO\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eMature cystic teratoma of the ovary\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eSCC\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003esquamous cell carcinoma\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003e125\u0026ndash;Cancer antigen 125\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003e19\u0026ndash;9\u0026ndash;Cancer antigen 19\u0026thinsp;\u0026minus;\u0026thinsp;9\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCEA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eCarcinoembryonic antigen\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eLDH\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eLactate dehydrogenase\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCT\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eComputed tomography\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eMRI\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eMagnetic resonance imaging\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eMDT\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eMultidisciplinary team\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eFIGO\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eInternational Federation of Gynaecology and Obstetrics\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate:\u003c/strong\u003e Not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent\u003c/strong\u003e:\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWritten informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor of this journal.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials:\u0026nbsp;\u003c/strong\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests:\u0026nbsp;\u003c/strong\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u0026nbsp;\u003c/strong\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors contributions:\u0026nbsp;\u003c/strong\u003eVB conceptualized, drafted, and supervised the manuscript. VB, LDB, NN, and SH drafted and edited the manuscript. AR performed the histopathological examination, provided interpretation of the histopathology findings and edited the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements:\u0026nbsp;\u003c/strong\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors’ information:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eVB: Obstetrics and Gynaecology, San Fernando General Hospital, South-West Regional Health Authority\u003c/p\u003e\n\u003cp\u003eVB: Medical Oncology, San Fernando General Hospital, South-West Regional Health Authority, Trinidad and Tobago\u003c/p\u003e\n\u003cp\u003eLDB: Obstetrics and Gynaecology, San Fernando General Hospital, South-West Regional Health Authority\u003c/p\u003e\n\u003cp\u003eNN: Obstetrics and Gynaecology, San Fernando General Hospital, South-West Regional Health Authority\u003c/p\u003e\n\u003cp\u003eSH: Obstetrics and Gynaecology, San Fernando General Hospital, South-West Regional Health Authority\u003c/p\u003e\n\u003cp\u003eAR: Department of Pathology, San Fernando General Hospital, South-West Regional Health Authority, Trinidad and Tobago\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eLi C, Zhang Q, Zhang S, Dong R, Sun C, Qiu C, et al. Squamous cell carcinoma arising in ovarian mature cystic teratoma: a systematic review. Gynecol Oncol. 2019;154(3):598\u0026ndash;604.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDos Santos L, Mok E, Iasonos A, Park KJ, Soslow RA, Aghajanian C, et al. Squamous cell carcinoma arising in mature cystic teratoma of the ovary: A case series and review of the literature. Gynecol Oncol. 2007;105(2):321\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHackethal A, Brueggmann D, Bohlmann MK, Franke FE, Tinneberg HR, M\u0026uuml;nstedt K. Squamous-cell carcinoma in mature cystic teratoma of the ovary: systematic review and analysis of published data. Lancet Oncol. 2008;9(12):1173\u0026ndash;80.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKoonings PP, Campbell K, Mishell DR Jr, Grimes DA. Relative frequency of primary ovarian neoplasms: a 10-year review. Obstet Gynecol. 1989;74:921\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYoshida Y, Kato N, Koshiyama M, et al. Molecular genetic analysis of ovarian squamous cell carcinoma arising from mature cystic teratoma. Int J Gynecol Pathol. 2000;19:354\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eUlker V, Numanoglu C, et al. The role of p53 in malignant transformation of ovarian dermoid cysts. Eur J Gynaecol Oncol. 2014;35:306\u0026ndash;12.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eO\u0026rsquo;Neill CJ, McCluggage WG. Morphological and immunohistochemical typing of ovarian cancer. Histopathology. 2011;58(4):539\u0026ndash;58.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTseng CJ, Chou HH, Huang KG, et al. Squamous cell carcinoma arising in mature cystic teratoma of the ovary. Gynecol Oncol. 1996;63:364\u0026ndash;70.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSato N, Kurman RJ, et al. Detection of HPV DNA in ovarian squamous cell carcinoma arising from MCT. Int J Gynecol Pathol. 1991;10:119\u0026ndash;28.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChiang AJ, Chen DR, Cheng JT, Chang TH. Detection of human papilloma virus in squamous cell carcinoma arising from dermoid cysts. Taiwan J Obstet Gynaecol. 2015;54(5):559\u0026ndash;66.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKikkawa F, Ishikawa H, et al. Clinical characteristics of malignant transformation of ovarian mature cystic teratoma. Obstet Gynecol. 1997;89:197\u0026ndash;202.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKido A, Togashi K, et al. MRI findings in dermoid cysts with malignant transformation. AJR Am J Roentgenol. 1999;172:445\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePark CH, Kim JY, et al. Surgical outcomes in malignant transformation of MCT. J Obstet Gynaecol Res. 2010;36:789\u0026ndash;95.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePowell JL, Dulaney DP, Yates WA, et al. Malignant transformation of MCT: clinical characteristics and management. J Reprod Med. 1998;43:1007\u0026ndash;11.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKumar A, Schneider V. Chemotherapy for squamous carcinoma arising in dermoid cysts. Cancer. 1983;51:2316\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSumi T, Ishiko O. Role of radiotherapy in malignant transformation of ovarian dermoid cysts. Int J Clin Oncol. 2001;6:341\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e\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":"squamous cell carcinoma, mature cystic teratoma, ovarian malignancy, malignant transformation, ovarian germ cell tumour","lastPublishedDoi":"10.21203/rs.3.rs-8575529/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8575529/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\u003eMalignant transformation of mature cystic teratomas (MCTs) of the ovary is rare, with squamous cell carcinoma (SCC) being the most common histologic subtype. Due to its nonspecific clinical presentation and similarity to benign dermoid cysts, preoperative diagnosis is often challenging, resulting in delayed recognition and poorer outcomes. Risk factors such as postmenopausal status, large tumour size, and elevated tumour markers should serve as red flags prompting clinical suspicion for malignant transformation within an ovarian teratoma.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase presentation:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe describe the case of a 52-year-old woman who presented with chronic abdominal distension, bloating, and early satiety. Imaging revealed large bilateral dermoid cysts with associated right-sided hydroureteronephrosis and an elevated CA-125 level. She underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy, omentectomy, appendectomy and peritoneal washings. Histopathology confirmed a moderately differentiated squamous cell carcinoma arising within a mature cystic teratoma, confined to the right ovary (pT1a).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSquamous cell carcinoma arising in a mature cystic teratoma represents a rare but clinically significant form of malignant transformation. This case underscores the importance of considering malignancy in postmenopausal women with large or symptomatic ovarian dermoid cysts and highlights the role of comprehensive histopathological evaluation in establishing an accurate diagnosis and guiding optimal management.\u003c/p\u003e","manuscriptTitle":"Squamous cell carcinoma arising within a mature cystic teratoma of the ovary in a postmenopausal woman: A case report and literature review","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-22 07:05:51","doi":"10.21203/rs.3.rs-8575529/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":"b54fe4a2-f9e2-4b75-9f1d-df9a20f995d8","owner":[],"postedDate":"January 22nd, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-01-25T04:39:01+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-22 07:05:51","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8575529","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8575529","identity":"rs-8575529","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}