Rupture of thoracic aorta caused by penetrating aortic ulcer.

We present the findings in a 57-year-old man with a rupture of the thoracic aorta that originated in a penetrating atherosclerotic aortic ulcer. It formed a large hematoma that clinically mimicked a true saccular thoracic aneurysm. The possibility of penetrating aortic ulcer should be considered in the differential diagnosis of aortic aneurysm.