Unusual appearance of intracranial fibromuscular dysplasia. A case report.

Fibromuscular dysplasia (FMD) of intracranial arteries is seen rarely and usually limited to the intrapetrosal internal carotid artery or carotid siphon. The authors report a case with recurrent subarachnoid hemorrhage diagnosed angiographically as FMD with extensive involvement of intracranial arteries. Angiography showed large fusiform dilatations and multiple aneurysms along the left intracranial internal carotid artery into its major branches, middle cerebral and posterior communicating arteries, and tip of the basilar and posterior cerebral arteries. Such an angiographic appearance has not been previously reported. Radiologic findings are demonstrated and possible pathophysiologic mechanisms are discussed.