Proximal left subclavian artery aneurysms: a case report and review of the literature.

Aneurysms of the proximal subclavian artery are extremely rare. A 39-year-old female with an incidental finding of a small proximal left subclavian artery aneurysm at its origin from the aortic arch is described. This was an incidental finding during workup for chest pain. No other vascular abnormalities were found and no obvious etiology was identified. The workup, plan for conservative treatment, and close follow-up are described. Although larger aneurysms and those in the middle and distal subclavian arteries, symptomatic or asymptomatic, are generally considered for surgical treatment, very little is known about the natural history of small proximal subclavian aneurysms.