Nephrogenic adenoma in a patient with transitional cell carcinoma of the bladder receiving intravesical bacillus Calmette-Guérin.

A 76-year-old-man was admitted to our hospital for a recurrent bladder tumor. He had received intravesical bacillus Calmette-Guérin (BCG) treatment for a transitional cell carcinoma of the bladder. A follow-up cystoscopy revealed a solitary papillary tumor in the left bladder wall. A transurethral cold cup biopsy revealed a nephrogenic adenoma without any evidence of malignant cells. We discuss the pathogenesis of nephrogenic adenoma and suggest that prolonged cystitis caused by intravesical BCG may play an etiological role.