Dolichoectasia of the right internal carotid artery diagnosed incidentally by MR angiography in a 17-year-old girl.

Dolichoectasia of the cerebral artery, a rare disorder of arterial elongation, dilatation, and tortuosity, usually involves the vertebrobasilar system in elderly patients with hypertension and is associated with the development of atherosclerosis in the aging process. We present a very rare case in a 17-year-old girl with multiple sclerosis of dolichoectasia of the supraclinoid segment of the internal carotid artery that was found incidentally on magnetic resonance angiography and seems to represent a congenital arterial malformation.