Immunoglobulin G4-Related Kidney Disease with Membranous Proliferative Glomerulonephritis Presenting with a Renal Pelvic Mass

Immunoglobulin G4 (IgG4)-related kidney disease is a chronic immune-mediated fibro-inflammatory disorder characterized by multiple organ infiltration with IgG4-positive plasma cells, storiform fibrosis, and obliterative phlebitis or tumefactive lesions. Previous studies have explored IgG4-related kidney disease, increasing our understanding of its clinical manifestations, and pathological and radiologic findings. However, IgG4-related kidney...