HIGH-INCIDENCE OF NEPHROGENIC ADENOMA OF THE BLADDER AFTER RENAL-TRANSPLANTATION

Background. Tumors of the bladder termed nephrogenic adenomas in kidne y allograft recipients are believed to develop as urothelial metaplast ic proliferations in response to mechanical trauma, chemical noxae, ir radiation, and bacterial or viral pathogens, We report on the incidenc e of nephrogenic adenoma of the bladder in patients who received renal transplants during a period of 7 years and 3 months at the University Hospital of Vienna. Methods. Diagnosis was obtained by cystoscopy and histological analysis. Nephrogenic adenoma was treated by transurethr al electroresection and administration of antibiotics in case of urina ry tract infections. Follow-up consisted of cytological controls of ur ine and bladder irrigation fluid as well as of cystoscopy every 3 mont hs. Results. In 7 of 1328 renal allograft recipients, nephrogenic aden oma could be detected after 7 to 60 months following renal transplanta tion. In five patients, recurrence was detected 9 to 23 months after d iagnosis of the initial lesion, No evidence of malignant degeneration was observed in any patient. Nephrogenic adenoma was not related to im munosuppressive therapy, cytomegalovirus disease, or gancyclovir thera py. Conclusions. We suggest that after successful transurethral electr oresection of nephrogenic adenomas, cytological controls are adequate every 3 months. Only in renal transplant patients with recurrence of v oiding disturbances, macrohematuria, or urinary tract infection are cy stoscopy and biopsy indicated in the routine follow-up regimen.