DOI: https://doi.org/10.36347/sjmcr.2026.v14i04.033

Pages: 723-727

Nephrogenic adenoma (NA) is an uncommon benign lesion of the urinary tract that arises from the proliferation of implanted renal tubular cells in areas of urothelial injury. This condition has the capacity to clinically and histologically mimic urothelial carcinoma, thereby posing a significant diagnostic challenge. The following report details the case of a 55-year-old male patient with a medical history of high-grade pT1 non–muscle-invasive bladder cancer (NMIBC), which was resected six years prior. The patient presented with recurrent gross hematuria, pollakiuria, and dysuria. Contrast-enhanced computed tomography (CT) revealed a suspicious posterior bladder wall lesion. Transurethral resection of the bladder tumor was performed, and histopathological examination revealed tubular and microcystic structures lined by bland cuboidal to flattened cells. Immunohistochemistry revealed strong positivity for PAX8 and negativity for GATA3, thereby confirming a diagnosis of nephrogenic adenoma. No recurrence was observed at 12 months of follow-up. This case underscores the significance of immunohistochemical analysis in distinguishing nephrogenic adenoma from urothelial carcinoma, particularly in patients with a prior history of bladder malignancy.