A case of IgG4-related lymphadenopathy, pericarditis, coronary artery periarteritis and luminal stenosis.

Immunoglobulin G4 (IgG4)-related disease is an emerging new clinicopathological disorder that is characterized by elevation of serum IgG4 levels and histological findings of IgG4-positive plasmacytic infiltration. IgG4-related disease may appear synchronously or metachronously in a wide variety of organs. The current patient was found to have pericardial effusion and retroperitoneal fibrosis. He was subsequently diagnosed with coronary artery stenosis. (18)F-FDG positron emission tomography showed enhanced FDG uptake in lymph nodes as well as pericardial and peri-aortic tissue. Histopathology of the mediastinal lymph node showed the infiltration of numerous IgG4-positive cells, leading to the diagnosis of IgG4-related lymphadenopathy with pericardial and periarterial involvement.