Abstract
Rheumatoid arthritis and interstitial pneumonitis were diagnosed in a 72-year-old man and thoracic computed tomography revealed an aortic arch aneurysm 50mm in diameter. Steroid therapy gave symptomatic relief and improved laboratory findings, but hyperglycemia and hypertension developed. Two months later the thoracic aneurysm ruptured, and computed tomography revealed expansion of the aneurysm to 60mm in diameter and surrounding hematoma. Emergency total arch replacement was performed successfully with deep hypothermic cardiopulmonary bypass and selective cerebral perfusion. The steroid therapy was considered to be responsible for the rapid expansion and rupture of the thoracic aneurysm. When prescribing steroids for a patient who has a concomitant atherosclerotic cardiovascular disease, we should not only control the steroidal side effects strictly, but also carefully watch the course of the atherosclerotic lesion.