Immunoglobulin G4-related disease is a systemic disease, recognized as extensive T-lymphocyte and IgG4-positive plasma cells. It can present as inflammatory pseudotumor in various organs. A female 75 years old, diagnosed IgG4-related autoimmune pancreatitis, presented with urinary retention. Pelvic examination showed well-defined, soft tissue mass, bulging from anterior vaginal wall. MRI pelvis demonstrated a huge periurethral mass, size 6.2 × 4.4 × 4.2 cm, encasing the urethra, extending from bladder neck to distal urethra, and mimicking the prostate gland. Tissue biopsy showed compatible with IgG4-related disease. Immunosuppresive drugs were given for few months and the patient could void normally.
