Persistent second cervical intersegmental artery in a case of possible PHACE syndrome.

The proximal segment of the vertebral artery most often consists of a persistent sixth cervical intersegmental artery that originates from the subclavian artery, but it may also derive from a fifth, fourth, or third cervical intersegmental artery (in decreasing order of frequency), or from a first thoracic intersegmental artery. The involvement of more cranial cervical branches is exceptional, with no known persistent first cervical intersegmental artery and possibly five cases of persistent second cervical intersegmental arteries reported so far. This report describes a patient with multiple arterial variations including right persistent second cervical intersegmental artery of common carotid origin, distal VA duplication, circumflex aortic arch, and segmental internal carotid agenesis in a context of possible PHACE syndrome.