Isolated retroaortic left innominate vein in an adult without cardiac or aortic anomalies.

Retroaortic innominate vein is an uncommon variant reported in patients with congenital heart disease. However, isolated retroaortic innominate vein without associated cardiac or arch anomalies is extremely rare. We present a case of a 68-year-old man who was found to have this anomalous variant incidentally on computed tomography (CT) of the thorax. We also briefly discuss its associations, embryology, and clinical significance.