Carotid Artery Dissection and Aneurysm with Styloid Process Fracture

Background: Mechanical stimulation may lead to internal carotid artery (ICA) dissection and aneurysm. Case Description: We encountered a rare case of ICA dissection and aneurysm with prolonged styloid process (SP) fracture. A 37-year-old sales worker presented with right-sided amaurosis fugax. After admission to a nearby optical clinic, he was admitted to our hospital. Computed tomography angiography (CTA) and digital subtraction angiography showed dissection and apparent aneurysmal change in the right cervical portion of the ICA. CTA also showed elongated SPs, so we diagnosed Eagle's syndrome, and fracture of the right-side process. After 2 weeks of antiplatelet therapy, the aneurysm enlarged and dissection remained, so we treated the patient with coil embolization and stenting. Conclusion: We encountered a rare case of ICA dissection and aneurysm with Eagle's syndrome. Endovascular treatment was performed because the SP was fractured.