Sonography and neuropathology of a congenital brain tumor: report of a rare incident.

A rare case of a congenital brain tumor was diagnosed by sonography in a fetus at 33 weeks' gestation. The ultrasound examination showed a large area of both increased echogenicity and echolucency in one hemisphere suggestive of brain tumor or hemorrhage. The neuropathological examination revealed an undifferentiated glial tumor with large areas of necrosis.