Separate origins of the left internal and external carotid arteries from the aorta in a patient with intracerebral hemorrhage.

Agenesis of the left common carotid artery with separate origins of the left internal and external carotid arteries from the aorta is an extremely rare anomaly. This anomaly is typically asymptomatic unless associated with other conditions. We report a case of separate origins of the left internal and external carotid arteries from the aorta in a patient with intracerebral hemorrhage. A 42-year-old man was transferred to our hospital by ambulance because of left hemiparesis. Computed tomography scan revealed right putaminal hemorrhage. Computed tomography angiography and digital subtraction angiography demonstrated independent origins of the left internal carotid artery and external carotid artery from the aortic arch. Right internal carotid angiography revealed blood supply to the left anterior cerebral artery and middle cerebral artery via the anterior communicating artery. The separate origins of the left internal and external carotid arteries from the aorta may cause hemodynamic stress to the contralateral side, leading to right intracerebral hemorrhage.