Aneurysms of the extracranial carotid arteries are in most cases secondary to atherosclerosis, but may also be due to degeneration, infection of the arterial wall (mycotic forms), congenital abnormalities, trauma, fibromuscular dysplasia, irradiation arteritis, dissecting aneurysm or non-specific causes.
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.