Extracranial carotid artery aneurysm

MR examination of the cranium revealed lacunar infarcts on the left cerebral hemisphere. Contrast-enhanced 3D MRA showed an extracranial internal carotid artery aneurysm measuring 3cm x 3cm x 2.5cm (Fig. 1). A carotid angiogram revealed an aneurysm at the left internal carotid artery distal to the bifurcation of the common carotid artery (Fig. 2). There was no history of neck injury.

The patient was treated surgically. Under general anaesthesia, resection of the aneurysm and restoration of the arterial flow by an internal saphenous venous graft between the internal and common carotid arteries was performed. The post-operative period was uneventful. During follow-up at 6 months, the patient remained asymptomatic. A carotid Doppler US examination showed no evidence of recurrent aneurysm or iatrogenic carotid stenosis.

A pulsatile neck swelling is the commonest presentation of an extracranial carotid artery aneurysm. Other symptoms include pain, transient ischaemic attacks, stroke and dysphagia. Differential diagnoses include carotid body tumour, cervical lymphadenopathy, tortuous carotid artery and other mass-like lesions.

The diagnosis of carotid artery aneurysm can easily be confirmed by a non-invasive carotid Doppler US examination. Digital subtraction angiography (DSA) remains the gold standard in treatment planning. Three-dimensional magnetic resonance angiography and conventional MR images can easily show the size of the aneurysm, extent of mural thrombus and anatomical relationship of the aneurysmsal neck to the parent artery. Owing to the potential complications of carotid artery aneurysm, including rupture with fatal haemorrhage and distal circulatory thrombo-embolism, early surgical or endovascular treatment is advocated.