Volume 16, Number 2Case ReviewImmunoglobulin G4–related Retroperitoneal Fibrosis of the PelvisAnthony DyerPeter M SadowErika BracamonteMatthew GretzerRetroperitoneal fibrosis (RPF) is a rare disease characterized by the replacement of normal tissue with fibrosis and/or inflammation. In this case, a 68-year-old man presented with RPF in the pelvis, a rare location for this disease. Biopsies were performed, which showed elevated levels of C-reactive protein, erythrocyte sedimentation rate, and, most importantly, immunoglobulin G4 (IgG4). It has been postulated that IgG4-related sclerosing disease is a systemic disease. Treatment has been successful with systemic corticosteroids. [Rev Urol. 2014;16(2):92-94 doi: 10.3909/riu0594] © 2014 MedReviews®, LLCRetroperitoneal fibrosisSerum immunoglobulin G4