[Giant aneurysm of the middle cerebral artery presenting with complex partial seizure. Case report].

A 24-year-old female who had had several attacks of complex partial seizures was admitted after minor head trauma. There was no neurological deficit on admission, but a large oval calcification was incidentally found in the left temporal region on the plain skull film. Computed tomography scan and carotid angiography revealed a giant thrombosed aneurysm which arose from the M2 portion of the left middle cerebral artery. Focal spike discharges were found on the left temporal region on conventional electroencephalography. Left frontotemporal craniotomy and opening of the left sylvian fissure disclosed a giant aneurysm at the M2 portion of the left middle cerebral artery. The neck of the aneurysm was buried in the dome of the aneurysm and the parent artery was curved at an acute angle at the site of the neck. The aneurysm was excised and end-to-end anastomosis of the main stem of the M2 portion was successfully performed. Postoperative course was uneventful and the patient became completely free from seizures. The surgical technique and the possible mechanism of complex partial seizure in this patient are described.