Multifocal IgG4-related aortitis and periaortitis simulating aortic dissection.

Immunoglobulin G4-related aortitis (IgG4-RA) is histologically characterized by the infiltration of IgG4 positive plasma cells and fibrosis in systemic organs and the elevation of serum IgG4 levels. The cardiovascular system is commonly involved with various possible presentations such as aortitis, arteritis, periaortitis, periarteritis, and inflammatory aneurysm. We present a case of a 48-year-old male without known previous medical history, admitted for further workup of long-standing chest pain and shortness of breath with suspected aortic dissection on initial assessment. Investigation with computed tomography angiography (CTA) and magnetic resonance angiography (MRA) indicated severe thoracic and abdominal aortoarteritis associated with an ascending thoracic aortic aneurysm, which was confirmed to be IgG4-RA on histopathologic analysis. Thoracic and abdominal IgG4-RA clinical and radiological presentation may simulate other causes of acute aortic syndrome such as aortic dissection, atherosclerotic aneurysm and inflammatory conditions. Accurate recognition of IgG4-RA diagnostic imaging features are essential for early diagnosis and treatment surveillance.