Spontaneous regression of arteriovenous malformations.

Spontaneous regression of an arteriovenous malformation (AVM) is quite rare. When a regression does occur, there is usually an associated factor, such as intracranial hemorrhage, operation, radiation therapy, or new neurological deficit. Twenty-one cases of AVM regression identified in the literature are reviewed. An additional case in which the resolution was totally spontaneous is presented. Regressions occurred over intervals ranging from 7 months to 21 years. Several mechanisms for regression are discussed.