Aneurysm of the vein of Galen: prenatal diagnosis and perinatal management.

An aneurysm of the vein of Galen is a rare arteriovenous malformation of the central nervous system. Fetal manifestations have included nonimmune hydrops, hydrocephalus, and intracranial hemorrhage. This anomaly may be diagnosed prenatally by several imaging modalities. A cystic cranial mass was identified by ultrasound in a fetus at 30 weeks gestation. Both pulsed-wave Doppler and color-velocity imaging studies suggested aneurysm of the vein of Galen was the most likely diagnosis. The fetus demonstrated no evidence of hydrops on serial ultrasound examinations. A 2430 g female infant was delivered vaginally at 35 weeks gestation. Postnatal management included transarterial embolization of the vessels feeding the aneurysm with craniectomy, an intra-aneurysmal balloon, and vascular microcoils. Hydrocephalus developed and a ventriculo-peritoneal shunt was placed. The infant has grown appropriately in the first year of life. An aneurysm of the vein of Galen may be diagnosed prenatally by real-time ultrasound, pulsed-wave Doppler, color-velocity imaging, or magnetic resonance imaging. The presence of this malformation should prompt close follow-up for the remainder of the pregnancy. Careful obstetric management and early postnatal intervention may lead to a favorable outcome.