A Case of Aortic Stenosis with Serum IgG4 Elevation, and IgG4-Positive Plasmacytic Infiltration in the Aortic Valve, Epicardium, and Aortic Adventitia

: A 74-year-old man was admitted for preoperative screening of aortic stenosis. Five months before this admission, he was found to have elevated serum immunoglobulin G4 (IgG4; 2,010 mg/dL). Computed tomography (CT) showed a soft tissue mass surrounding the abdominal aorta, suggestive of IgG4-related periaortitis. CT coronary angiography showed perivascular thickening of the right coronary artery, and subsequent coronary angiography showed a multi-vessel disease. The patient underwent aortic valve replacement and coronary bypass surgery. Immunohistochemical analysis showed IgG4-positive plasmacytic infiltration in specimens from the aortic valve, epicardium, and aortic adventitia, suggestive of the possible role of IgG4-related immune inflammation for the pathogenesis.