A CASE OF EXTRACRANIAL INTERNAL CAROTID ARTERY ANEURYSM

A case of extracranial internal carotid artery aneurysm which is relatively rare is presented, together with some review of literatures. A 50-year-old woman was admitted to another hospital because of sudden onset of severe headache and a tumor in the right side of theneck. MRI showed that the neck tumor was neurinoma. The patient was operates on. Intraoperatively, the tumor was found to be an aneurysm of the right internal carotid artery (ICA). The patient was referred to our institution. On 3 D-CT, a saccular aneurysm was located at the right ICA, which was 30×25mm in size with mural thrombus. Brain MRI visualized a cerebral infarction of the right frontal lobe without any abnormal neurological findings. The patient underwent an aneurysmectomy and interposition of saphenous vein graft. The intraoperative carotid stump pressure was 62 mmHg ; however, an outlying internal shunt was placed because of the cerebral infarction and the prolonged clamping time of the right ICA. Intraoperative electroencephalographic monitoring did not show any abnormal changes, and the graft blood flow volume was sufficient. Postoperative course was uneventful and an arteriogram showed no stenosis of the bypass graft. Pathological examination revealed that the aneurysm was true type with disruption of medial elastica and inflammatory cellular infiltration in all layers, which was diagnosed as nonspecific vasculitis.