Immunoglobulin G4(IgG4) related disease (IgG4-RD) is a chronic fibro-inflammatory condition characterized by immunohistochemically positive IgG4-positive plasma cell infiltrates in the tissues, elevated serum IgG4 levels, and fibrosis in the affected organs. The most frequent complaints are associated with obstructive phlebitis, mass and tumor-like tissue swelling. Our case was admitted with a complaint of breast mass, and lymphocyte infiltration, dense fibrosis foci were detected in the breast biopsy. Besides, serum IgG4 levels were found to be increased and IgG4 related disease was diagnosed. The importance of glucocorticoid and immunosuppressive therapy in the treatment of this rare chronic inflammatory disease, which can be confused with many clinical conditions, has been mentioned.
Keywords: Glucocorticoid, Immunoglobulin G4 related disease, Immunosuppressive therapy, Breast mass
