Ventricular obstruction secondary to vascular malformations.

Enlarged veins in two vascular malformations blocked the cerebrospinal fluid outflow pathways, causing hydrocephalus. Both patients presented not with the usual clinical picture (hemorrhage, seizure, etc.), but with signs of increased intracranial pressure. Computed tomography and angiography were necessary to understand the pathophysiology. An arteriovenous malformation was responsible for the first patient's headache, and a venous varix was the causative lesion in the second patient. Hydrocephalus caused by a venous varix has not been reported before.