IgG₄-related disease: an atypical presentation of steroid-responsive renal mass

IgG 4 -related disease (IgG 4 -RD) is a systemic fibroinflammatory disease characterised by dense lymphoplasmacytic infiltration rich in IgG 4 -positive plasma cells, storiform fibrosis and obliterative phlebitis. Serum IgG 4 levels are typically elevated but half of the patients had normal serum IgG 4 levels. IgG 4 -RD represents a spectrum of diseases that involve various organs such as the pancreas, liver, kidneys, and salivary glands often...