Nephrogenic adenoma of the urinary bladder: clinical experience and review of the literature.

BACKGROUND: Nephrogenic adenoma (NA) is a rare disease of the urinary tract. We report our clinical experience with this disease in the urinary bladder and review the literature.

METHODS: Between April 1994 and July 2004, 8 patients were diagnosed with NA of the urinary bladder: 3 men and 5 women, aged 23-77 years (mean 49.6). Multiple predisposing factors were analyzed. The mean follow-up time was 56 months.

RESULTS: NA was not associated with transitional cell carcinoma in our series. All patients had recurrent urinary tract infection. Urinary tuberculosis was diagnosed in 2 patients. Two patients had undergone previous open urosurgery, and 4 patients had received previous endourologic management. A history of urolithiasis was found in 1 patient. Previous long-term urinary catheterization was noted in 3 patients. Two patients had received pelvic radiation therapy for cervical cancer. Urinary frequency and microscopic hematuria were found in all patients. All nephrogenic adenomas were treated with transurethral resection. Recurrent nephrogenic adenomas were diagnosed in 3 patients (median time to disease relapse, 7 months). Recurrent tumors were also treated with the endourologic method.

CONCLUSION: NA is an uncommon benign metaplastic lesion occurring in the urothelium. Transurethral resection of NA provides a definite diagnosis and relief of symptoms. The recurrence rate of NA is relatively high, so careful and long-term follow-up is necessary.