Both immunohistochemical and morphologic studies showed that the ETT is mainly composed of chorionic-type intermediate trophoblastic cells.[1] These cells are arranged in nests, cords, sheets, and trabeculae in a background of prominent hyaline material and geographic necrosis.[6] Immunohistochemical staining of the tumor cells showed patchy reactivity for cytokeratin 18, pancytokeratin, epithelial membrane antigen, human placental lactogen (hPL), β-hCG, and p63.[8]. The gene discussed is KRT18; the disease is neoplasm.