Combined use of alpha-fetoprotein and ultrasound in the prenatal diagnosis of arteriovenous fistula in the brain.

A case of arteriovenous fistula in the brain detected by the combined use of maternal serum alpha-fetoprotein (AFP) and ultrasound in the third trimester of pregnancy is described. The maternal serum AFP concentration at 34 weeks of gestation was 300 ng/mL (2.3 times the median). Stage II diagnostic ultrasonography at 37 weeks revealed a large midline cystic mass, contiguous to a normal-appearing lateral ventricle and surrounded by an abnormal heterogeneous zone of increased echogenicity. At birth, the cord blood AFP concentration was 2 SD above the mean. Subsequent histopathologic examination revealed a vein of Galen aneurysm and fistula in the brain.