Splaying of the carotid bifurcation caused by a cervical sympathetic chain schwannoma.

Splaying of the carotid bifurcation revealed by an imaging study is usually indicative of a carotid body tumor, but there are other possibilities. To promote awareness of a cervical sympathetic chain schwannoma as another cause of splaying of the carotid bifurcation, we present a case of cervical sympathetic chain schwannoma, with an additional 7 cases in the English-language literature, and discuss the relationship between the great vessels of the neck and a carotid body tumor or a schwannoma of the cervical sympathetic chain or vagus nerve from an anatomic viewpoint. We conclude that splaying of the carotid bifurcation with hypervascularity suggests a carotid body tumor, whereas in cases without hypervascularity, a cervical sympathetic chain schwannoma is another possibility. Vagus nerve schwannomas can separate the internal jugular vein and internal carotid artery, but seldom widen the carotid bifurcation.