Bilateral Somatically Derived Germ Cell Tumors With 12p Gains Arising in High-grade Serous Carcinomas of the Ovary: A Case Report and Review of the Literature.

Epithelial ovarian neoplasms are commonly observed in older patients, while germ cell tumors (GCTs) typically present in young individuals. When GCTs are detected in patients over 35 yrs old, they often have an associated epithelial component, a phenomenon known as somatically derived GCTs. We report a unique case of mixed GCT involving bilateral ovaries with a background of high-grade serous carcinoma, including a yolk sac tumor and choriocarcinoma in the mixed GCT component. Somatically derived GCTs are rare with only 45 cases of ovarian carcinoma with somatic yolk sac tumor reported to date. Pathologists face diagnostic challenges in identifying somatically derived GCTs, as they can mimic high-grade epithelial neoplasms. Somatically derived GCTs have poor outcomes, therefore, precise diagnosis is crucial for prognostic and therapeutic considerations.