Spontaneous pseudoaneurysm of the extracranial internal carotid artery

A 57-year-old woman with a history of breast cancer presented to otolaryngology for evaluation of a pea-sized asymptomatic left neck mass. Flexible laryngoscopy showed no abnormalities, but MRI of the neck with contrast showed a left carotid space mass measuring 1.3 × 1.2 × 1.6 cm. Differential diagnosis was reported as schwannoma, lymph node, or paraganglioma. High-resolution duplex carotid ultrasonography showed to-and-fro flow in the left mid-internal carotid artery (ICA) suggestive of a pseudoaneurysm (Panel A). A definitive tract could not be appreciated by Doppler imaging, likely due to the posterior location of the pseudoaneurysm neck behind the active chamber. Computed tomography angiography (CTA) of the brain confirmed the diagnosis (Panel B) and an intimal defect was noted intraoperatively. Complete resection of the pseudoaneurysm was performed with end-to-end anastomosis (Panel C). Pathology was consistent with aneurysmal dilatation of an elastic-transitional-type artery with degenerative changes. The patient is doing well on aspirin 81 mg daily at the 1-year follow-up.

Panel A Panel B Panel C

Extracranial carotid artery aneurysms are rare, with an incidence of 0.5–1%, ¹ and pseudoaneurysms of cervical ICAs are even rarer. ² They commonly occur as a result of trauma, deep neck space infections or atherosclerosis. ³ Other less common etiologies include fibromuscular dysplasia, Marfan’s syndrome or radiation. Affected patients may be completely asymptomatic or experience pain, fever, dysarthria, hoarseness, syncope or transient ischemic attack. ² Physical exam may reveal bruit, cranial nerve deficits or a pulsating neck mass. The clinical course of such aneurysms is unpredictable and life-threatening complications can occur including stroke, delayed massive epistaxis, cranial nerve deficits, and even death. ² Several surgical options exist; however, excision and reconstruction with vein interposition graft remains the most definitive approach with an acceptable complication rate. ¹ Endovascular therapy with stent grafts and coil embolization has been described with unknown long-term patency rate. ¹

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