Common carotid artery dissection: a rare cause of acute neck swelling.

Spontaneous carotid artery dissection is a rare condition with potentially devastating consequences. Internal carotid artery and vertebral artery dissections have been implicated as the cause of 20% of strokes occurring in patients younger than 45 years. We describe a very rare case of a nontraumatic common carotid artery dissection in a 45-year-old man that was initially misdiagnosed as a sternocleidomastoid hematoma. This case highlights the need for vigilance for this often-missed diagnosis, as well as the indication for noninvasive imaging in unidentified neck swellings.