CT demonstration of extracranial carotid artery aneurysms.

Aneurysms arising from the extracranial carotid arteries are uncommon lesions. Clinically, they may present as lateral masses in the superior cervical area, as medial masses in the tonsillar fossa or parapharyngeal region, or as a mass palpable in both areas. Tenderness or pain may or may not be present. Pulsation is usually detectable. Embolic neurological episodes are a common event leading to discovery of these lesions. Etiologies include trauma, atherosclerosis, fibromuscular dysplasia, infection, and congenital predisposing factors. We report the CT appearance of this condition in three patients. In all three patients (four aneurysms) the CT findings were characteristic. Thus far, we have discovered only one account in the English literature that included the CT demonstration of an extracranial carotid aneurysm.