Dissecting aneurysms of the basilar artery in 2 patients.

Abstract
An uncommon consequence of intracranial vascular disease is the intramural dissection of blood, or dissecting aneurysm. A 69 yr old man with chronic subarachnoid hemorrhage from a posterior fossa mass lesion and a 30 yr old man with migraine and a brain stem stroke illustrate the diverse etiologic, clinical, radiographic and pathologic characteristics of this unusual lesion.