Unilateral agenesis of the internal carotid artery.

Unilateral agenesis of the internal carotid artery (ICA) is an extremely rare anomaly. Diagnosis is often incidental in a radiological examination. Recognition of this anomaly has important clinical implications because other life-threatening conditions can be associated and it must be taken into account when planning carotid surgery. We report a case of 64-year-old man with agenesis of the ICA.