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

OBJECTIVE

To assess our experience in the treatment and clinical outcome of bladder nephrogenic adenoma (NA) updating and reviewing the literature concerning this issue.

PATIENTS AND

METHODS

From September 1976 to June 1999, bladder NA was diagnosed in 8 patients: 6 men and 2 women with a 3:1 male ratio, aged 26-80 (mean 58.3) years. Follow-up ranged from 4 to 194 (mean 93.5) months.

RESULTS

NA was associated with transitional cell carcinoma in 3 cases. Predisposing factors were assessed in all patients. Previous surgery of the lower urinary tract was detected in 5 cases: ureterocystoneostomy in 2, partial cystectomy in 1, repair of vesicouterine fistula in 1, and multiple urethroplasties in 1. Previous endoscopic treatments were carried out in 2 patients, transurethral resection of the prostate in 1 and repeated transurethral resection of the vesicle in the other. A history of intravesical instillation of bacillus Calmette-Guérin was assessed in 1 case. Patients complained of irritative voiding symptoms in 6 cases and hematuria in 2. Endoscopically, the lesions appeared polypoid and multifocal in 5 patients, and flat and single in 3. The lesions were removed endoscopically, providing relief of symptoms in all cases. Histopathology assessed the diagnosis of nephrogenic adenoma, detecting focal atypic cells in 1 case only. Five patients (63%) relapsed 2-24 months after management. Recurrences were also treated endoscopically.

CONCLUSIONS

Clinical and endoscopic features of bladder NA are not specific, simulating urothelial carcinoma or chronic cystitis. Endoscopic management allows accurate histological diagnosis and provides long-lasting relief of symptoms. NA needs careful and long-term follow-up, because of the high risk of recurrences and the potential neoplastic degeneration of the metaplastic urothelium.