Acute infarction in a patient with agenesis of the internal carotid artery and transcavernous anastomosis.

A 70-year-old man presented with left-sided weakness and dysarthria. His brain MRI and magnetic resonance angiography demonstrated acute infarctions in the bilateral middle cerebral artery territories in a setting of agenesis of the right internal carotid artery (ICA) with transcavernous anastomosis, a rare developmental anomaly. In this setting, atherosclerotic disease in the unilateral common carotid artery or ICA can induce acute infarctions in the bilateral anterior circulation.