[Nephrogenic adenoma of the upper and lower urinary tract. Apropos of 22 cases]

Nephrogenic adenoma (NA) is a lesion that can present in the urothelium--from the renal pelvis to the urethra-, and is considered to be immature metaplasia arising from chronic aggression. We report 22 cases of NA in 21 patients that had been diagnosed and treated in our service from 1975 to 1990. The lesion was found at all levels of the urinary tract: renal pelvis (1 case), ureter (1 case), bladder (16 cases) and urethra (4 cases). The present series was comprised of 15 males (one with bladder NA and recurrence in urethra) and 6 females, with ages ranging from 24 to 79 years (mean 55). The diagnosis was made on the histological findings in all cases and the etiology of the lesion was multiple: previous surgery (11 cases), previous or coexisting urothelial carcinoma (8 cases), intracavitary chemotherapy and/or pelvic radiotherapy (3 cases), previous history of tuberculosis (5 cases), interstitial cystopathy (4 cases), lithiasis (2 cases), permanent catheter (3 cases) and urethral stenosis (1 case). Treatment and prognosis was influenced by the underlying urological disease. NA per se does not carry an unfavourable prognosis.