Ruptured supratentorial arteriovenous malformations associated with venous aneurysms.

Six patients with ruptured supratentorial arteriovenous malformation (AVM) and an associated venous aneurysm (ectasia, dilatation, varix, pouch) are described. At presentation, patients ranged in age from 16 to 61 years and were equally distributed according to sex. Maximal AVM diameter was between 2.5 and 5.0 cm at presentation while the maximal size of the venous aneurysm ranged between 0.75 and 3.0 cm. One patient had multiple venous pouches while 5 patients had a single venous aneurysm. Three patients had a single bleed; 1 patient had 2 bleeds; and 2 patients had 3 bleeds. Hemorrhage around the venous aneurysm was seen in 4 of 5 patients who underwent magnetic resonance imaging of the brain. One patient, who suffered 3 bleeds over a several year period, had both an increase in the size of the venous aneurysm as well as enlargement of the AVM. The following features did not appear to influence hemorrhage: AVM size or location; venous aneurysm size or location; age; sex; pattern; location or number of draining veins; or external circulation feeders. These observations suggest that a venous aneurysm may increase the risk of hemorrhage from a supratentorial AVM and may be an ominous feature.