ABSTRACT
Nephrogenic adenoma is a rare benign lesion of bladder that may be confused with malignant lesions. There is a strong relation with urinary tract irritation and intravesicle instrumentations. Nephrogenic adenoma was initially thought to originate from urothelial metaplasia; however, no solid proof is available. We present a case of 55-year-old lady with urinary problem. Cystocopic examination showed a sessile mass, and biopsy revealed circumscribed proliferation of tubules, cysts, and papillae that were lined by low cuboidal to columnar epithelial cells. Nephrogenic adenoma can be a significant diagnostic pitfall due to the presence of certain histological features such as the presence of enlarged nuclei with prominent nucleoli. Immunohistochemistery study was strongly positive for CK7, P504S, CD10, and EMA, but negative for CK20, PSA, and P63