Abstract
We present an extremely rare case of an arteriovenous malformation (AVM) in the territory of the middle cerebral artery, the main trunk of which was occluded asymptomatically. Immediately after an uneventful excision of the entire AVM, massive brain swelling occurred unexpectedly and was treated successfully with high dose barbiturate therapy associated with other standard measures of controlling increased intracranial pressure. The underlying pathophysiological mechanisms leading to the massive intraoperative brain swelling in this case are discussed.