Epithelioid trophoblastic tumor of the broad ligament: a case report and review of the literature.

We report an epithelioid trophoblastic tumor, a recently delineated type of gestational trophoblastic tumor (GTT), discovered in the right broad ligament of a 41-year-old woman. The patient had gestational trophoblastic disease and was treated with methotrexate regimen 15 times 10 years earlier. The yellowish, spongy tumor with tiny hemorrhage spots was located in the right broad ligament, adherent to the right ovary. Microscopically, the tumor was circumscribed, with a pushing border, and the epithelial-differentiated tumor cells grew in cords, nests, and sheets within which were aggregates of hyaline material and necrotic debris. Most tumor cells were mononuclear with distinct cell borders, eosinophilic cytoplasm, and had nuclei with occasional indistinct nucleoli. Scattered multinucleated cells consistent with syncytiotrophoblastic cells were also present. Immunohistochemical staining revealed strong diffuse reactivity for cytokeratins (AE1/AE3, CAM 5.2, CK18), and focal reactivity, mainly in syncytiotrophoblastic cells, for beta-human chorionic gonadotropin, human placental lactogen, and inhibin-alpha. The histologic and immunohistochemical features were characteristic of epithelioid trophoblastic tumor and helped to distinguish the tumor from other trophoblastic tumors and squamous cell carcinoma. Our unusual findings in this case included a high level of serum beta-human chorionic gonadotropin, an unusual tumor location, and a higher Ki-67 proliferative index of 47.2%.