Distal aneurysms of the superior cerebellar artery and posterior inferior cerebellar artery feeding an associated arteriovenous malformation: case report.

The authors report a case of two distal aneurysms of the cerebellar arteries, one arising from the vermian branch of the posterior inferior cerebellar artery, the other arising from the hemispheric branch of the superior cerebellar artery, and both feeding an associated arteriovenous malformation (AVM). The aneurysm of the distal posterior inferior cerebellar artery was considered the source of a cerebellar hemorrhage because of the location of a hematoma in the cerebellar vermis. The life-threatening hematoma was evacuated in an emergency operation 6 hours after the acute onset of symptoms. The cerebellar aneurysms and the AVM were clipped or extirpated successfully after the patient's condition improved. The association of two rare types of aneurysms with an AVM strongly supports the theory that increased hemodynamic stress derived from the AVM plays an important role in aneurysm formation. The authors think that one should operate on the symptomatic lesion first or both the aneurysm and the AVM in the same operative procedure.