Nephrogenic adenoma of the bladder in renal transplant recipients: a report of 9 cases with assessment of deoxyribonucleic acid ploidy and long-term followup.

Purpose: We evaluated the outcome of nephrogenic adenoma, a benign tumor rarely encountered in renal transplant recipients.

Materials And Methods: Between 1985 and 1993, 9 renal transplant recipients with a nephrogenic bladder adenoma removed by endoscopic resection were followed for 24 to 88 months (mean 40). Tumor deoxyribonucleic acid ploidy was assessed by flow cytometry at diagnosis and/or relapse.

Results: The relapse rate was 88%. The tumors were diploid and of low proliferating potential, and showed no malignant transformation.

Conclusions: Our study confirms the lack of premalignant potential of nephrogenic adenomas. However, since transplant recipients might be at increased risk for bladder cancer, they should be followed closely.