Aneurysm of the extracranial internal carotid artery caused by fibromuscular dysplasia.

A case of aneurysm of the extracranial internal carotid artery (ICA) caused by fibromuscular dysplasia (FMD) is reported. The patient also had an aneurysm of the contralateral intracranial ICA, but the renal arteries were normal. A review of the literature shows extracranial ICA aneurysms to be uncommon, with only 3% caused by FMD. The surgical management of such difficult lesions at the base of the skull is discussed.