Presentation
Incidental finding in persistent cough and suspicious chest x-ray.
Patient Data
There is a dominant right-sided aortic arch from which the right common carotid and right subclavian arteries originate.
A smaller incomplete left aortic arch, from which the left common carotid and left subclavian arteries originate, is demonstrated coursing towards but without communication with a bulge (diverticulum) at the descending aorta. The segment of the left aortic arch between the left subclavian artery and descending aorta is not opacified, likely atretic.
The descending aortic diverticulum does not give rise to an aberrant subclavian artery (unlike in Kommerell diverticulum) and likely represents a remnant of the distal left aortic arch.
Case Discussion
This is a case of incomplete double aortic arch with distal left arch atresia, which can easily be mistaken for a right aortic arch with mirror-image branching. This is a rare vascular ring anomaly wherein the nonpatent distal left arch persists as a fibrous cord tethering the anterior left arch with the descending aortic diverticulum. The presence of the fibrous cord results to a more posterior position of the left arch in the mediastinum in contrast to a typical position of the innominate artery in right aortic arch with mirror-image branching.