Immunoglobulin G4-related periaortitis mimicking an intramural hematoma.

Immunoglobulin G4 (IgG4)-related sclerosing disease in the cardiovascular system is a recently proposed disease entity, which is still unfamiliar to most clinicians. We present a case of IgG4-related periaortitis of the ascending aorta mimicking an intramural hematoma in the computed tomography (CT) scan, which led to an unnecessary surgery. IgG4-related periaortitis needs to be considered in the differential diagnosis in a patient with thickened aortic wall because the disease should be treated medically in light of its good response to steroid therapy.