Aortic and Mitral Valve Replacement Due to Extensive Inflammatory Immunoglobulin G4-Related Pseudotumor.

A 64-year-old woman with extensive tumorous infiltration of the mitral and aortic valves underwent partial resection of a tumor of the left ventricular outflow tract and replacement of both affected valves. Histology revealed an inflammatory pseudotumor with a significant number of immunoglobulin-G4-positive plasma cells. The histologic and clinical findings suggested immunoglobulin-G4-related disease of the heart.