We report a case of a 64-year-old woman who was referred to our hospital complaining of hemoptysis and severe back pain. A chest computed tomography revealed impending rupture of the aortic arch aneurysm associated with an aberrant right subclavian artery. She had been treated with oral steroids for idiopathic thrombocytopenic purpura (ITP) with good control. She underwent emergency total aortic arch replacement under deep hypothermic circulatory arrest. Intraoperative transesophageal echocardiogram showed moderate aortic regurgitation and we found a quadricuspid aortic valve. Aortic valve replacement was also performed. Steroids were given intravenously during and after the operation as a steroid cover and platelets were transfused as well. Although her early postoperative course was uneventful, recurrence of ITP occurred 3 weeks after surgery. Increased dose of steroids caused the patient to be susceptible to infection. She suffered from high fever and suddenly died of massive hemoptysis due to dehiscence of the distal anastomosis caused by graft infection 60 days postoperatively. To the best of our knowledge, this is the second case report from Japan describing an aortic arch aneurysm repair in a patient with ITP and is also the first report of combined congenital anomalies with aberrant right subclavian artery and quadricuspid aortic valve.