Massive congenital intracranial teratoma: a report of two cases.

Although intracranial teratoma is a well-recognized entity in the differential diagnosis of pediatric brain tumors, massive congenital intracranial teratoma replacing the cerebral hemispheres of a neonate has seldom been reported. We describe two such instances that histologically exhibit predominantly neuroepithelial differentiation. In 1 case serial prenatal ultrasonography revealed ventricular dilatation prior to identification of the lesion. Theories of pathogenesis are briefly discussed.