Abstract
IgG4-related disease (IgG4-RD) is a new clinical entity characterized by lymphoplasmacytic lesions rich in IgG4-positive plasma cells. Myocardial involvement is extremely rare and not a typical cardiovascular manifestation of IgG4-RD. We report a rare case of IgG4-RD-associated myocardial mass causing severe aortic incompetence, successfully treated with surgery and corticosteroids. (Level of Difficulty: Intermediate.).