Mature Cystic Ovarian Teratoma with Squamous Cell Carcinoma Transformation: a Case Report and Literature Review.

Objectives: Cancerous transformation in mature cystic ovarian teratoma is rare. Herein, we reported a case of squamous cell carcinoma transformation in mature cystic ovarian teratoma and performed an in-depth literature review to highlight the risk factors, prognosis, and suggested treatment for these patients. Case presentation: We report a 66-years old postmenopausal woman diagnosed with a 120x90 (mm) mass at the left adnexa compatible with mature cystic ovarian teratoma. Following resection, the histopathological investigations showed malignant transformation in her mature cystic ovarian teratoma, and the immunohistochemistry for cytokeratin (CK) 5/6 and tumor protein 63 (P63) indicated squamous cell carcinoma transformation. She has been observed for her stage IA tumor and has been cancer-free for 6 months. Conclusions: Although malignant transformation in mature cystic ovarian teratoma is rare, it should be suspected if certain risk factors, e.g., elderly and high tumor size, exist. Stage IA patients' prognosis is favorable, and chemotherapy is not recommended.