IgG4-related disease of the mitral valve demonstrated by immunohistochemistry

IgG4-related disease (IgG4-RD) is known to involve the cardiovascular system as aortitis or periaortitis1; however, the number of reported valvulopathies are exceptionally rare. This case is the first with immunohistochemistry proven mitral valve involvement.A 72-year-old Korean woman with paroxysmal atrial fibrillation and end-stage renal disease due to long-standing diabetes and hypertension presented to the emergency department with near-syncope and dyspnoea with exertion. Further evaluation revealed three-vessel coronary artery disease and severe mitral valve stenosis due to suspected rheumatic mitral valve disease with a mitral valve area of 0.62 cm2, peak gradient of 15.5 mm Hg and mean velocity of 136 cm/s. The patient underwent three-vessel coronary artery bypass graft surgery and mitral valve replacement with a 27 mm pericardial bioprosthesis. Both the anterior and posterior chordae tendineae were …