Primary endodermal sinus tumor of the endometrium presenting as "recurrent" endometrial adenocarcinoma

Primary endodermal sinus tumor of the endometrium is an extremely rare malignancy with few reports in the world literature.

A case of primary endodermal sinus tumor of the endometrium is presented. The case is unusual in several aspects: it occurred in a patient with a history of breast cancer and long-standing tamoxifen use, and was diagnosed only after presenting as an apparent unexpected recurrence of endometrial adenocarcinoma. The tumor recurred despite initial cytoreductive surgery and combination chemotherapy.

Rare types of endometrial cancers may present as unexpected recurrences of previously resected endometrial adenocarcinomas. Appropriate therapy depends on obtaining sufficient tissue to establish an accurate diagnosis to ensure selection of proper chemotherapeutic agents.