Two unusual variants of internal carotid artery aneurysms due to fibromuscular dysplasia

Aneurysms of the internal carotid artery (ICA) secondary to fibromuscular dysplasia (FMD) are extremely rare. We report two unique variants of extracranial ICA aneurysms due to FMD. The first patient was a hypertensive 51-year-old woman who was found to have a nontraumatic, nonmycotic saccular pseudoaneurysm of the right ICA. The second patient was a 46-year-old woman who presented with 90% stenosis and a focal dissecting aneurysm of the right ICA. Both underwent successful aneurysm resection with interposition saphenous vein grafting after anterior subluxation of the mandible. A review of the literature revealed only 21 other reported cases of aneurysms of the extracranial ICA due to FMD; all were managed successfully with surgical repair. Surgery can be performed with minimal or no morbidity, even in the distal ICA, if the exposure is adequate.Presented at the Fourth Annual Winter Meeting of the Peripheral Vascular Surgery Society, Breckenridge, Colo., January 21–23, 1994.