A case of giant right coronary artery aneurysm due to IgG4-related disease

A man diagnosed with immunoglobulin G4 (IgG4)-related disease at the age of 65 years underwent abdominal aortic replacement due to an abdominal aortic aneurysm. In the same hospitalization period, a small coronary artery aneurysm was noticed. He was treated with corticosteroids and his serum IgG levels returned to normal. After experiencing sudden chest pain at age 74 years, coronary angiography showed that the size of the aneurysm had increased dramatically. He underwent coronary artery bypass graft and coronary artery resection without using cardiopulmonary bypass. Thus, we conclude that observation of aneurysms in patients with IgG4-related disease is important, even under corticosteroid therapy.