A 70-year-old man with stable coronary artery disease presented to the emergency department (ED) with new onset of right arm and leg weakness, as well as dysphasia.

His workup included a computed tomogram (CT) scan of his head that showed an acute stroke in the distribution of the left middle cerebral artery. A carotid duplex ultrasound examination revealed no significant bilateral carotid artery stenosis but did show a 1.5 cm aneurysm with a small amount of mural thrombus in the proximal left internal carotid artery (ICA) (Figure 27-1). A magnetic resonance angiogram (MRA) of the neck confirmed the presence of the proximal left ICA aneurysm, but there was also a question of stenosis at the proximal and distal extent of the aneurysm (Figure 27-2).

A catheter-directed angiogram was therefore performed to rule out any other intimal defects given the discrepancy between the MRA and the duplex. No significant stenosis was identified, and no other luminal irregularities were seen (Figure 27-3).

After he functionally recovered from his stroke, he was offered left carotid aneurysm repair with a vein interposition graft (Figures 27-4 and 27-5).

This was accomplished and he recovered uneventfully. Further workup revealed no other aneurysmal disease.

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  Rare pathologic finding. Several series exist that are small and often span decades.^{1,2,3,4, and 5} One study reported the incidence of pro-cedures performed for carotid artery aneurysm to be less than 1% of the total carotid procedures over a 20-year period.¹

  
  
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  Men are much more commonly afflicted than women, as would be expected since the most common etiology of carotid aneurysms is a degenerative, atherosclerotic pathology.

  
  
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  No association with the occurrence of other aneurysms has been shown.