epithelioid trophoblastic tumor

Arising from the putative chorionic-type intermediate trophoblast, epithelioid trophoblastic tumor is a recent addition to the spectrum of gestational trophoblastic diseases.

Frequently, epithelioid trophoblastic tumor involves the uterine cervix and is misdiagnosed as invasive squamous-cell carcinoma.

CGH

The pathogenesis of the epithelioid trophoblastic tumor is poorly understood, and its molecular analysis is essentially lacking.

Comparative genomic hybridization analysis show a balanced chromosomal profile without detectable gain or loss of the genome. Chromosomal alterations detectable by conventional comparative genomic hybridization are not features of epithelioid trophoblastic tumors. (18820674)

DNA genotyping shows unique paternal alleles, confirming the trophoblastic nature of the tumors.

In difficult cases, the presence of the paternal alleles demonstrated by DNA genotyping is a powerful diagnostic application in separating an epithelioid trophoblastic tumor from its maternal mimics, particularly the far more common squamous-cell carcinoma of the uterine cervix. (18820674)

Localization

 broad ligament (15104307)

Synopsis

 mononuclear tumor cells

• distinct cell borders,
• eosinophilic cytoplasm
• nuclei with occasional indistinct nucleoli

 scattered multinucleated cells consistent with syncytiotrophoblastic cells were also present.

Immunochemistry

 cytokeratins AE1/AE3+
 CAM5.2+
 CK18+
 high Ki-67 proliferative index

References

 Xu ML, Yang B, Carcangiu ML, Hui P. Epithelioid trophoblastic tumor: comparative genomic hybridization and diagnostic DNA genotyping. Mod Pathol. 2008 Sep 26. PMID: 18820674