Persistent fifth aortic arch left subclavian aneurysm in an adult.

Persistent fifth aortic arch is so rare an anomaly that only seven cases have been reported. We treated an adult with this anomaly in which there was a single lumen aortic arch, single arterial trunk and left subclavian aneurysm. The patient underwent corrective surgery. From an analysis of the eight cases, this anomaly can be divided into two groups, depending on the aortic arch. The first group of six had double lumen aortic arch. All in this group had intra and/or extra cardiac anomalies, and only two with only PDA underwent ligation. The second group of two had a single lumen aortic arch and corrective surgery was done. Thus, those patients with a persistent fifth aortic arch should be classed into the first or second group, according to the angiographical findings.