Epithelioid trophoblastic tumor: A case series

Area of Science:

• Gynecologic Pathology
• Reproductive Endocrinology
• Oncology

Background:

• Epithelioid trophoblastic tumor (ETT) is an exceedingly rare form of gestational trophoblastic neoplasm.
• ETTs typically manifest with abnormal vaginal bleeding in women of reproductive age, often with mildly elevated beta human chorionic gonadotropin (β-hCG) levels.

Purpose of the Study:

• To present a series of four ETT cases, detailing their histomorphology, immunoprofiles, and diagnostic challenges.
• To contribute to the understanding of this rare entity to improve diagnostic accuracy and patient management.

Main Methods:

• Retrospective analysis of four ETT cases, including clinical data, histomorphology, and immunohistochemical staining.
• Evaluation of tumor cell morphology, arrangement, and specific markers such as AE1/AE3, p63, GATA3, hPL, SALL4, and Ki67.

Main Results:

• All four patients were of reproductive age with a mean pre-treatment hCG level of 665.24 mIU/mL.
• Microscopically, tumors showed epithelioid morphology in nests/sheets with eosinophilic cytoplasm, vesicular nuclei, and prominent nucleoli. Hemorrhage, necrosis, and hyaline material were common.
• Immunohistochemistry revealed diffuse positivity for AE1/AE3 and p63 in all cases. GATA3 was positive in one case, hPL was focally positive in one, and SALL4 was negative in two cases. The mean Ki67 index was 19.2%.

Conclusions:

• ETT diagnosis can be challenging due to its rarity and overlapping features with other neoplasms.
• Consistent immunohistochemical findings, particularly AE1/AE3 and p63 positivity, aid in diagnosis.
• Surgical management (hysterectomy) in this series resulted in favorable outcomes, with all patients alive at follow-up.