Background: Ovarian carcinomas may produce human chorionic gonadotropin (HCG) or HCG-like substances and may even contain syncytiotrophoblast cells, but a true choriocarcinomatous component has not been described in these tumors.
Methods: Two cases of poorly differentiated ovarian carcinoma with choriocarcinomatous components are reported. Pathologic findings were correlated with immunohistochemical stains, hormonal effects, and clinical behavior.
Results: Each tumor contained a circumscribed, extensively necrotic and hemorrhagic brown nodule. Microscopically, the nodules exhibited a mixture of cytotrophoblast and syncytiotrophoblast. The syncytiotrophoblast capped cytotrophoblast and was strongly positive for beta-HCG. In one of the cases, a transformation zone composed of poorly differentiated carcinoma with occasional beta-HCG-positive cells was observed between a mucinous cystadenoma and the choriocarcinomatous elements. The two cases exhibited activation of the ovarian stroma in the form of condensation and luteinization. Extra-abdominal metastases developed early in both patients and, despite multiagent chemotherapy, they died shortly postoperatively.
Conclusions: Choriocarcinoma may rarely develop as a result of dedifferentiation of common epithelial ovarian tumors. Recognition of choriocarcinomatous components in ovarian carcinomas is important because of its association with aggressive behavior.