Chorangioma with trophoblastic proliferation

Only two examples of the entity of chorangiocarcinoma, in which there is a proliferation of both the vascular and epithelial components of the placental villi, have been reported in the literature. To test the hypothesis that chorangiocarcinomas are actually more common than implied by the literature, histological sections of chorangiomas were reviewed. Syncytiotrophoblast and cytotrophoblast proliferation, with nuclear atypia, similar to that found in trophoblastic neoplasia, were seen in 15 of 23 cases. Thus, 65% of chorangiomas fulfilled the diagnostic criteria to warrant re-assignment as "chorangiocarcinoma". The proliferation index of the cytotrophoblast in the tumor as measured by MIB-1 (Ki-67) immunostaining was significantly higher in "chorangiocarcinoma" than chorangioma (35.4% vs 15.7%, P