Unilateral Hypoplasia of the Internal Carotid Artery

Hypoplasia of the internal carotid artery (ICA) is a rare congenital anomaly. Most of the patients are asymptomatic. When clinically symptomatic it presents as cerebral ischemia or hemorrhage. Carotid artery hypoplasia should not be confused with other conditions which may have a similar appearance such as arterial dissection, atherosclerosis, vasculitis and tubular fibromuscular hyperplasia. Hypoplasia of the ICA is usually discovered incidentally by computed tomography or magnetic resonance imaging. We report three cases of ICA hypoplasia which were discovered incidentally on computed tomography angiography (CTA). One of the three patients described an ipsilateral amaurosis fugax associated with the hypoplasia of the right internal carotid artery.