Hypoplastic internal carotid artery stenosis with a low-lying carotid bifurcation causing cerebral ischemia.

Congenital abnormalities of the internal carotid artery (ICA) are infrequent and can be associated with aberrations of the Circle of Willis. A 47-year-old gentleman presented with transient neurological symptoms and cerebral infarction and carotid Doppler showed a stenotic right ICA. Subsequent computed tomographic angiography showed a hypoplastic ICA with a low-lying bifurcation at the C6 level and aplasia of the anterior communicating artery. This patient was commenced on aggressive medical therapy and at 7-month follow-up was symptom-free. This case report highlights the need for a centralized registry with long-term follow-up data in order to identify optimal management.