Epithelioid trophoblastic tumor: A case series.

An epithelioid trophoblastic tumor (ETT) is an extremely rare gestational trophoblastic tumor. Cases of ETT present with abnormal vaginal bleeding in women of reproductive age group with marginally elevated beta human chorionic gonadotrophin (B-hCG) levels. Here, we describe a series of four patients (all were females) including histomorphology, immunoprofiles, and diagnostic difficulty of this rare entity. All cases were in their reproductive age group. The mean pre-treatment hCG level was 665.24 (mIU/mL). Microscopically, all cases had a tumor showing an epithelioid appearance arranged in large nests and sheets. Individual tumor cells were round to polygonal with abundant eosinophilic cytoplasm, with central vesicular nuclei and prominent nucleoli. Areas of hemorrhage, necrosis, and intercellular hyaline-like material deposition were identified in all cases (100%). Immunohistochemically, tumor cells in all cases showed diffuse positivity for AE1/AE3 and p63 (100%). GATA3 was available in one case (25%), which was positive in the tumor cells. In one case (25%), hPL was focally positive, and in one case (25%), it was negative. SALL4 was performed in two cases (50%) and was negative in tumor cells. The mean Ki67 labeling index was 19.2 (range 10-30%). All four patients underwent surgical intervention and were treated with hysterectomy. The mean follow-up in this series was 39.4 months (range 6-70), and all patients are alive to date with a mean survival of 32.8 months (range, 4-67).