[Impending rupture of a pseudoaneurysm in the descending thoracic aorta: a rare clinical course].

A sixty-year-old male manifested high fever, bloody sputa and an abnormal shadow in the left hilus on chest X-ray film. He was treated with antibiotics as for a infections lung disease. But back pain which he had been suffered from didn't improve. He was referred to the second hospital with suspicion of lung neoplasm. He underwent radiation therapy. The shadow in the left hilus had been increasing in size with the radiation therapy. On CT scanning, the shadow was recognized as an impending aneurysm along the descending thoracic aorta. He was referred to our hospital and operated upon in emergency basis. On operative findings, the aortic aneurysm located from the distal portion of the left common carotid artery and was huge sacklar shape. In surgical procedure, the entrance in the descending aorta was closed with a vascular patch graft because the aortic wall around the entrance was normal and unaffected. Postoperative course was uneventful. We should learn some warning from this case.