Nephrogenic adenoma: a form of adenomatous metaplasia of the bladder. A clinical and electron microscopical study.

3 additional cases of "nephrogenic adenoma" of the bladder are added to the 20 previously reported cases. Light and electron microscopic studies of the first 2 cases support the hypothesis of urothelial metaplasia. The name "adenomatous metaplasia" should replace "nephrogenic adenoma". Malignant change occurred in the third case, suggesting that this ought to be regarded as a potentially dangerous from of metaplasia. In the absence of malignant change, ileocaecocystoplasty with subtotal cystectomy afforded symptomatic cure in 2 cases: radical cystectomy was performed in the third because of malignant adenocarcinoma.