[Differential diagnosis of multilocular bladder tumors in young patients: nephrogenic adenoma of the bladder in a 25-year old male cystinuria patient].

The occurrence of malignant neoplasms of the urinary tract in patients below the age of 40 years is rare. Nevertheless, finding masses with suspicious malignant appearance in young patients should alert the examiner particularly against the background of reported cases of urothelial or urachal carcinoma in childhood or adolescence. This report presents the case of a 25-year-old male patient with recurrent urolithiasis due to cystinuria. During elective stone therapy via ureteroscopy a tumor of distinct malignant appearance was conspicuous and was immediately resected. The histopathological findings revealed the diagnosis of a nephrogenic adenoma.