Double left brachiocephalic vein with a preaortic course: a rare finding.

A double left brachiocephalic vein is an uncommon anatomic variation. Among these, a accessory branch with preaortic course is extremely rare. In this case, both branches of the left brachiocephalic vein were anterior to the aortic arch. We describe the computed tomography findings with volume-rendering imaging of this rare anatomic variation.