Prenatal diagnosis of bilateral retinoblastomas by multimodality fetal imaging: case report and review of the literature.

Retinoblastoma is the prototypic genetic tumor. Caused by mutations in the RB1 gene, retinoblastomas are heritable in 40% of the cases and, in such cases, tumors are bilateral in 80%, unilateral in 15%, and trilateral in 5% of the cases. Trilateral retinoblastoma is a term that describes bilateral retinoblastomas plus a midline suprasellar or pineal neuroectodermal tumor.