Placental involvement in congenital hepatoblastoma.

We describe extensive placental involvement by hepatoblastoma in a 2600 g, 33-week estimated gestational age (EGA) hydropic female fetus with the hepatoblastoma otherwise limited to the liver. The placenta weighed 1190 g and histopathologic examination revealed diffuse tumor emboli in chorionic villous vessels. The placental tumor exhibited a cytologic appearance similar to the primary tumor and showed strong alpha-fetoprotein staining. Although unusual, other congenital tumors, including neuroblastoma and leukemia, have also been described metastatic to the placenta. This case emphasizes the important role of careful histopathologic examination of the placenta which, combined with immunohistochemistry and clinicopathologic correlation, may establish a diagnosis and possibly obviate the need for invasive neonatal diagnostic procedures.