IgG4-related disease (IgG4-RD) is a chronic, immune-mediated disorder that can affect multiple organs, causing inflammation, fibrosis, and long-term organ damage. I uncommonly see these patients as they often present as a retroperitoneal mass concerning for a connective tissue malignancy however biopsied proven IgG4 related non-malignant disease requiring immunosuppressant treatment which I often did as there …
