aortic regurgitation developed seven years after mediastinal radiation therapy report of a case we report on radiationinduced valvular dysfunction in a 41yearold woman who developed aortic regurgitation with clinical symptoms requiring aortic valve replacement seven years after mediastinal radiation therapy for carcinoma of the breast she was treated with cobalt radiation therapy of 4000 rads to her left mediastinum the excised threecuspid aortic valve was edematous and densely fibrotic without commissural fusion histological examination strongly suggested that the aortic valve with diffuse fibrosis destruction of elastic fibers and bizarre nucleus in fibroblasts had been induced by mediastinal radiation therapy to our knowledge symptomatic radiationinduced valvular dysfunction in the aortic position has been reported infrequently with only eleven reported cases in this case symptomatic aortic regurgitation was diagnosed seven years after mediastinal radiation therapy it is emphasized that longterm followup is important for patients receiving mediastinal radiation therapy