Abstract
A 68-year-old male was admitted as an emergency case because of two severe back pain episodes in one week. Chest X-ray showed a marked prominence of the aortic knob. A remarkable bulging of the distal aortic arch and a crescentic low density area along the descending aorta on enhanced chest CT suggested a closing aortic dissection. Operation revealed extensive collapse of the very fragile intima of the aneurysmal wall and extraluminal hematoma along the descending aorta due to bleeding from the ruptured site. The ruptured aneurysm of this type should be accurately differentiated from the DeBakey type III closing aortic dissection which can be followed up medically.
