Primary ovarian mucinous cystic tumor with prominent theca cell proliferation and focal granulosa cell tumor in its stroma: case report, literature review, and comparison with Sertoli-Leydig cell tumor with heterologous elements.

A 73-year-old woman was found to have a 22 cm unilateral multilocular mucinous cystic tumor of the ovary. Microscopic examination showed a routine appearance of the epithelial component, which ranged from benign to borderline to low-grade carcinoma. The stromal component was unusual because of a striking cellular theca cell component in the stroma, which, in turn, merged with a component of adult granulosa cell tumor. The "parent" neoplasm in this case and 3 other similar cases in the literature appears to be the mucinous neoplasm, in contrast with the other example of mucinous neoplasia associated with sex cord neoplasia, the Sertoli-Leydig cell tumor with heterologous elements, in which the "parent" neoplasm is likely the Sertoli-Leydig cell tumor.