[Nephrogenic adenoma in intestinal mucosa. A case in urethro-sigmoid anastomosis]

To describe a case of nephrogenic adenoma occurring in the intestinal mucosa of the neobladder urethro-sigmoid anastomosis in a patient who had undergone cystectomy for a bladder carcinoma.

Of 14 cases of nephrogenic adenoma in 11 patients, one involved the lamina propria of large bowel mucosa. A 67-year-old patient submitted to radical cystoprostatectomy and orthotopic bladder substitution using a detubulized sigmoid neobladder due to multicentric G3 pTa, pTis urothelial bladder carcinoma had two episodes of stricture of the distal anastomosis. After the second episode, endoscopic resection of the area was performed. Histological examination of the specimen disclosed nephrogenic adenoma of the intestinal mucosa.

Nephrogenic metaplasia has been observed in the intestinal mucosa of patients undergoing different urological procedures. To our knowledge, our patient is the third case involving large bowel mucosa reported in the literature. These three cases suggest that nephrogenic adenoma might not be a metaplastic process specific to the urothelium.