Giant aneurysm of the internal carotid artery in the carotid canal.

A case of giant aneurysm of the intrapetrous portion of the internal carotid artery, with intracranial and extra-cranial extension in an eight-year-old girl, is reported. Intracranial extension was demonstrated by the presence of a large sac projecting above the petrous shadow in a frontal carotid angiogram, and upward displacement of the middle cerebral artery in the post-ligation angiogram. Extracranial extension was shown clinically as a pulsating mass in the nasopharynx, and also radiologically as a widened medial coronoid space. Erosive destruction of the petrous bone and its neighbourhood produced palsies of the 6th, 7th, 8th, 9th and 10th cranial nerves. There was appreciable recovery in the cranial nerve palsies when the patient was assessed clinically two weeks after ligation of the internal carotid artery.