Giant vein of Galen malformation in an adult.

Vein of Galen malformations (VoGMs) are rare vascular malformations resulting from persistent shunting of primitive choroidal vessels into the median prosencephalic vein of Markowski. VoGMs are associated with poor clinical outcome with a reported 76.7% mortality if left untreated. We present an exceedingly rare case of a giant, untreated VoGM measuring 7.8 × 5.5 × 7 cm in a 42-year-old man. The embryologic origin, classification, clinical manifestations, and treatment options of VoGMs are discussed with a review of pertinent literature.