Penetrating atherosclerotic ulcer aneurysm of the innominate artery.

Penetrating atherosclerotic ulcer of the aorta is uncommon, and usually develops in the descending thoracic aorta. Rarely this condition involves the branch vessels of the aorta. We report a case of ruptured aneurysm of the innominate artery resulting from penetrating atherosclerotic ulcer. Open surgery was the treatment of choice for the ruptured aneurysm, while conservative treatment was recommended for the associated penetrating atherosclerotic ulcers of the descending aorta.