Management of ureteral IgG4-Related Disease: The great masquerader

IgG4-related disease (IgG4-RD) is a systemic fibro-inflammatory condition that can mimic malignancies, including ureteric urothelial carcinoma (UCC). This case report describes a 65-year-old female presenting with obstructive uropathy due to IgG4-related ureteritis. Initial imaging suggested UCC, however ureteric biopsy was negative. Elevated serum IgG4 levels (3.77 g/L) supported the diagnosis of IgG4-related ureteritis. Treatment with methotrexate, prednisolone, and rituximab led to significant improvement, with subsequent imaging showing resolution of obstructive uropathy. This case highlights the importance of considering IgG4-RD in the differential diagnosis of ureteric malignancies to prevent unnecessary invasive procedures and optimize patient outcomes through appropriate immunosuppressive therapy.