Definition
A benign urogenital proliferation that may be found in the bladder, urethra, renal pelvis or ureters. It is thought to represent a reaction of the urothelium to injury2 by instrumentation, surgery or calculi. When the lesion develops in renal transplant recipients, the lesions are composed of donor cells, indicating that they probably represent implanted detached renal tubules3.
This is an uncommon lesion of adults.
The lesions may be single or multiple.
Nephrogenic adenoma has a variable architecture; papillary, tubular, nested, hobnail or solid. The hobnails may line vessels-like structures. Small tubules may have a pseudoinfiltrative pattern. Dilated tubules filled with eosinophilic material produce a thyroidised appearance. A basal layer is lacking. There may be cytological atypia with focally prominent nucleoli, but mitoses are absent. The stroma may be oedematous or inflammatory. Calcification and ossification occur3.
|
|
various sites |
bladder |
prostate |
||
|
3/161 |
4/41 |
||||
|
0/223 |
0/161 |
0/41, 1/112 |
|||
|
|
|
3/102 |
|||
|
|
9/92 |
||||
|
4/161 |
1/41, 5/92 |
||||
|
|
0/161 |
0/41 |
|||
In prostatic urethra / extending into prostate: prostatic carcinoma. Demonstration of origin from the urethra helps in the diagnosis of nephrogenic adenoma. Both may express P504S1. Positivity for PSA favours prostatic adenocarcinoma, while negativity suggest nephrogenic adenoma.
signet ring cell, clear cell or papillary adenocarcinoma
This page last revised 1.11.2004.
©SMUHT/PW Bishop