Epithelioid trophoblastic tumor presenting as an ovarian mass in a postmenopausal woman.

Epithelioid trophoblastic tumor (ETT) is a rare neoplasm derived from chorionic-type intermediate trophoblastic cells. Most cases of ETT are intrauterine and present during reproductive age. We report a case of ovarian ETT developing 47 yr after the patient's last pregnancy. A 75-yr-old woman transferred to our hospital because of multiple pulmonary masses which was diagnosed as sqaumous cell carcinoma in another hospital. PET-CT revealed a huge solid mass in the pelvic cavity, suspicious for ovarian malignancy. Serum β-hCG was 57,971 mIU/mL. Hysterectomy and bilateral salpingo-oophorectomy were performed. Gross examination showed an enlarged right ovary, measuring 17×14×7 cm. The cut surface was yellow-tan and solid with extensive areas of necrosis. The uterus was unremarkable. The histologic finding was the same as the previous lung biopsy. The tumor consisted of monomorphic cells with abundant eosinophilic cytoplasm, forming solid sheets and nests. There was geographic tumor cell necrosis with hyaline materials. Immunohistochemically, cytokeratin 7 and p63 showed diffuse reactivity in the tumor cells. There was focal staining for β-hCG. Ki-67 proliferative index was about 80%. This case indicates that ETT can rarely occur in postmenopausal women and to the best of our knowledge, our patient is the oldest reported case of ETT to date.