Epithelioid Trophoblastic Tumor: Clinicopathologic and Immunohistochemical Analysis of Three Cases

Epithelioid trophoblastic tumor is an unusual type of trophoblastic tumor. Here we report on the clinicopathologic and immunohistochemical features of three cases of epithelioid trophoblastic tumor. All three patients were of reproductive age and presented with vaginal bleeding and mild elevation of human chorionic gonadotropin (hCG). All patients underwent a hysterectomy. The tumors consisted of epithelioid intermediate trophoblastic cells that were mononucleated and eosinophilic, or showed clear cytoplasm on microscopic examination. One case presented with a focal choriocarcinoma component. Immunohistochemically, the tumors displayed diffuse positivity for cytokeratin 18, E-cadherin, epidermal growth factor receptor, and p53 and focal positivity for p63 and hCG. However, expression of α-inhibin and placental alkaline phosphatase was almost negative. Tests for human placental lactogen and epithelial membrane antigen were also negative in all cases.