Atherosclerotic pseudoaneurysm of the ascending aorta.

Pseudoaneurysms in the ascending aorta most commonly occur as a complication of surgical procedures at this site. They have also been reported in association with trauma, infection, aortitis, and other disorders. Pseudoaneurysm formation in the descending aorta or arch may occur as a result of penetrating ulcers in the presence of severe atherosclerotic plaque.