Communicating Segment Aneurysm of Internal Carotid Artery Associated with Saltzman's Type III Persistent Trigeminal Artery: A Case Report.

Persistent trigeminal artery (PTA), also called primitive trigeminal artery, represents the most common embryonic remnant of fetal circulation in adulthood, (only after fetal pattern of posterior communicating artery [PComA]) with an estimated incidence of between 0.1% and 0.76%. The permanence of this fetal pattern constitutes an incidental finding in most cases, however, may be associated with aneurysms, arteriovenous malformations, trigeminal neuralgia, and other types of fetal circulation persistency. A patient with giant aneurysm in the communicating segment of the right internal carotid artery, associated with the presence of PTA and fetal pattern of PComA, also on the right side is reported.