Extrauterine Epithelioid Trophoblastic Tumor Arising in the Ovary With Multiple Metastases: A Case Report

Epithelioid trophoblastic tumor is a neoplasm of the chorionic-type intermediate trophoblasts. It is considered a rare gestational trophoblastic disease and is frequently misdiagnosed as carcinoma. Extrauterine epithelioid trophoblastic tumor has been reported in multiple anatomical sites. We report a case of a 50-year-old woman who presented with abdominal pain and distension. Her initial β-human chorionic gonatotropin level was 806.7 IU/L. Imaging showed a large complex ovarian mass with peritoneal and subcapsular hepatic deposits as well as pulmonary nodules. Morphological features of the tumor and its immunohistochemical reactivity to CK8/18, CK7, p63, and CD10 were consistent with the diagnosis of an extrauterine epithelioid trophoblastic tumor arising from the ovary. The differential diagnoses, including other ovarian tumors, were ruled out on the basis of morphology and negative immunostaining to a relatively extended panel of antibodies. A prolonged follow up of these cases and the recognition of such rare tumors in unusual sites are crucial to the diagnosing pathologist and treating physician.