IgG4-Related Diseases Involving Bilateral Renal Pelvises Successfully Treated with Steroid Therapy

Immunoglobulin (Ig) G4-related diseases are very rare diseases and are difficult to diagnose and treat. Here, we report a rare condition, an IgG4-related disease involving the bilateral renal pelvises, which was successfully treated with steroid therapy. A 64-year-old female was admitted with left flank pain and hematuria. Computed tomographic images showed irregular enhancing masses around the bilateral renal pelvises and lymph nodes in the left para-aortic area. A histopathological examination of a renal needle biopsy revealed numerous cells that were positive for IgG and more than 10 IgG4-positive cells per high-powered field. The IgG4/IgG ratio was more than 40%. Her serum IgG4 level was elevated to 1440 mg/dL, and her IgG4/IgG ratio was 82.1%. After a diagnosis of IgG4 sclerosing disease, a double-J ureteral stent was inserted and steroid therapy was performed for 20 weeks. Her symptoms dramatically improved, and the follow-up images showed a resolved state. There was no relapse of the disease for more than 6 months after the removal of the stent.