[Three cases of IgG4-related disease associated with urinary tract obstruction]

IgG4-related disease (IgG4RD) is a novel clinical entity characterized by tissue infiltration of IgG4-positive plasma cells. We report here 3 cases of IgG4RD associated with urinary tract obstruction. Patient 1 was a 59-year-old male who complained of difficulty on urination. A CT scan showed bilateral ureteral wall thickness, hydronephrosis, and an enlarged prostate. His serum IgG4 was 817 mg/dl. We made a diagnosis of IgG4RD and performed bilateral ureteral stenting and steroid therapy. A significant reduction in the size of the lesion was detected, and IgG4 was decreased to 272 mg/dl. He was doing well after removal of the ureteral stent. Patient 2 was a 51-year-old female who complained of bilateral swelling of the submaxillary gland. A CT scan showed left ureteral wall thickness and hydronephrosis. Her serum IgG4 was 1,020 mg/dl. We made a diagnosis of IgG4RD and performed left ureteral stenting and steroid therapy. A significant reduction in the size of the lesion was detected, and IgG4 was decreased to 337 mg/dl. She was doing well after removal of the ureteral stent. Patient 3 was a 64-year-old male who underwent evaluation for autoimmune pancreatitis. He complained of back pain and bilateral hydronephrosis was detected. His serum IgG4 level was 649 mg/dl. Bilateral ureteral stenting was performed based on a diagnosis of IgG4RD. He did not receive steroid therapy because of poorly-controlled diabetes mellitus. After insertion of the ureteral stent, hydronephrosis and back pain were relieved. We could only find a few case reports in the literature on IgG4RD associated with urinary tract obstruction. It is important for clinicians to bear in mind that IgG4RD sometimes causes urinary tract obstruction.