Immunoglobulin G4-Related Periaortitis Involving the Aortic Arch Mimicking a Mediastinal Tumor

Immunoglobulin G4 (IgG4)-related sclerosing disease is a recently proposed systemic fibroinflammatory disease entity, with periaortitis as a representative manifestation in the cardiovascular system. We present a case of IgG4-related periaortitis involving the aortic arch and proximal great vessels, mimicking an anterior mediastinal tumor on computed tomography. In patients with a soft tissue mass along the aortic wall, IgG4-related periaortitis should be included as a differential diagnosis and timely serologic investigation should be performed to prevent unnecessary surgery, because the disease shows a remarkable response to corticosteroids.