Angiographically occult and spontaneously thrombosed large brain arteriovenous malformation.

Treatment for brain arteriovenous malformations (AVM) include combinations of surgery, radiosurgery and embolization. Very rarely, spontaneous obliteration may occur, especially among small lesions with single superficial vein drainage and prior bleeding. We report the case of a large symptomatic AVM, without history of hemorrhage or prior treatment, in which self-obliteration was noted at surgery.