[Agenesis of the left internal carotid artery, common carotid artery and main trunk of the external carotid artery associated with multiple cerebral aneurysms: case report].

A case of agenesis of the left internal carotid artery, common carotid artery and main trunk of external carotid artery with multiple cerebral aneurysms is presented. No similar case has been reported before. A 70-year-old man who had severe headache was admitted to the neurological department of Matsuyama Shimin Hospital. On admission he demonstrated nuchal rigidity and motor aphasia. CT scan revealed subarachnoid hemorrhage with intracerebral hematoma in the left temporal area. Right common carotid angiography, bilateral retrograde brachial angiography and aortography demonstrated an agenesis of the left internal carotid artery, common carotid artery and main trunk of external carotid artery with aneurysms of the anterior communicating artery, left middle cerebral artery and basilar tip. And these revealed that the left middle cerebral artery was fed from the basilar artery via the dilated left posterior communicating artery, and the left ophthalmic artery was originated from the left middle cerebral artery. CT of the base of the skull revealed no carotid canal on the left side. We confirmed these findings by operation. The importance of altered hemodynamic forces on the circle of Willis produced by the agenesis of the internal carotid artery and the embryological considerations are discussed.