Fetomaternal hemorrhage caused by intraplacental choriocarcinoma: a case report and review of literature in Japan.

Fetomaternal hemorrhage induced by intraplacental choriocarcinoma is considered to be extremely rare. We herein describe a neonate with severe anemia caused by intraplacental choriocarcinoma that was histopathologically identified after birth. Furthermore, we reviewed three other such cases in Japan. As a result, the incidence of intraplacental choriocarcinoma may be higher than previously estimated. Therefore, we suggest that the placenta should be examined in any suspected cases of fetomaternal hemorrhage.