IgG4-Related Disease in Urological Practice: A Case Series of Mistaken Malignancies

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibro-inflammatory condition first recognized in 2001, primarily associated with autoimmune pancreatitis, and later identified in various organ systems. The peculiar tendency to form tumefactive lesions mimics infiltrative malignancy, leading to misdiagnosis and inappropriate treatment. Involvement of the urinary tract and its presentation to urologists remain uncommon, with only a limited number of published case reports. We report our experience with IgG4-RD, elucidating the clinical presentations, diagnostic dilemmas, and subsequent management of four patients. Each case was initially presented as a diagnostic challenge, necessitating multidisciplinary discussion. Presentations included renal pelvic masses (unilateral and bilateral), a suprarenal mass, and a retroperitoneal mass causing bilateral hydroureteronephrosis. In all cases, initial imaging raised the suspicion of malignancy, prompting aggressive surgical interventions, including nephroureterectomy, nephrectomy, and partial nephrectomy. Subsequent histopathological evaluation confirmed the diagnosis of IgG4-related disease. IgG4-RD in the urinary tract is uncommon often mimicking malignancy. Early suspicion and minimally invasive biopsy for accurate tissue diagnosis, along with multidisciplinary evaluation, is crucial for diagnosing IgG4-related disease involving the urinary tract and avoiding unnecessary extirpative surgery.