Non-trophoblastic tumor of the placenta with combined histologic features of chorangioma and leiomyoma.

Chorangioma is the most common non-trophoblastic tumor of the placenta, which represents an excessive vascular proliferation within chorionic villi. While the histologic picture of a chorangioma may vary greatly from lesion to lesion, the presence of abundant smooth muscle tissue within a chorangioma has not been previously reported. Herein we report a case of a 34-year-old primigravida woman with a peculiar mesenchymal placental tumor, characterized by combined features of chorangioma and leiomyoma; large lobules of numerous small blood vessels within loose stroma, separated by broad bundles of smooth muscle fibers. Genetic studies by means of PCR excluded maternal and confirmed placental origin of the lesion.