ABSTRACT
Epithelioid trophoblastic tumor (ETT) is an unusual variant of gestational trophoblastic tumor that is closely related to choriocarcinoma and placental site trophoblastic tumor (PSTT) but shows different morphologic, immunohistochemical features. ETT grows in a nodular pattern compared with the infiltrative pattern of PSTT. Histologically the tumor is characterized by uniform population of mononucleate intermediate trophoblastic cells that resemble the trophoblastic cells in the chorionic laeve, so we called them "chorionic-type intermediate trophoblast". Immunohistochemically ETT was positive for cytokeratin, epithelial membrane antigen(EMA) and staining for human placental lactogen (hPL) and human chorionic gonadotrophin (hCG) was generally patchy, focal or negative whereas PSTT contained more hPL-positive cells than hCG-positive cells. ETT can behave in a malignant fashion such as distant metastasis. We experienced a case of ETT by clinical result, pathologic finding, so we report a case with brief literature review.