Carotid artery dissection associated with an elongated styloid process.

A 51-year-old man presented with right orbital pain and Horner syndrome three weeks previously. Although magnetic resonance imaging (MRI) showed no intracranial abnormalities, time-of-flight imaging of MR angiography (Picture A) detected an intimal flap and T1-weighted imaging (Picture B) indicated an intramural hematoma in the right internal carotid artery (ICA) at the cervical segment. Threedimensional computed tomographic angiography (Picture C, D) revealed an elongated styloid process close to the right ICA. Transient compression of the ICA by the styloid process induced by neck rotation was associated with ICA dissection. Aspirin was prescribed and the patient’s symptoms gradually disappeared. MRI performed six months later showed restoration of the ICA dissection. Eagle first reported that an elongated styloid process can cause symptomatic compression of the neighboring structures (1), occasionally in association with ICA dissection (2). Therefore, an elongated styloid process is an important cause of ICA dissection.