IgG4-related retroperitoneal fibrosis: A case report and review of literature.

Idiopathic Retroperitoneal fibrosis is a rare clinical condition recently identified as an autoimmune process related to Immunoglobulin G4 (IgG4) deposition. Herein we report a case of a 46 year old male presenting with 4 months history of backache, fever, flank pain and leg swelling for 2 weeks. Investigations revealed acute kidney injury diagnosed as a result of bilateral ureteric obstruction. This was later confirmed to be retroperitoneal fibrosis on CT scan and biopsy. Histopathology was consistent with IgG4 related disease. Treatment with immunosuppressive agents showed reduction in the fibrosis and normalization of the kidney functions. We discuss the IgG4 related retroperitoneal fibrosis in detail along with its varied presentations.