[Pathological and immunohistochemical analyses of 32 cases of nephrogenic adenoma]

To observe clinical and pathological features of nephrogenic adenoma (NA), and to find some useful immunohistochemical markers for its diagnosis.

The clinical features of 32 NA patients were obtained. Each case underwent microscopic observation and immumohistochemical staining. The primary antibodies were α-methylacyl-CoA racemase (AMACR, P504S), cytokeratin AE1/AE3, cytokeratin 7 (CK7), cytokeratin 20 (CK20), paired-box 2 (PAX2), paired-box 8 (PAX8), vimentin, membrane metallo-endopeptidase (MME, CD10), prostate specific antigen (PSA), high molecular weight cytokeratin (34βE12), P63 and carcinoembryonic antigen (CEA).

NA mainly involved old men, and the bladder was the commonest location. The macroscopic features were prevalently small polypoid or papillary lesions, ranging from 1 mm to 10 mm (mean=4). The typical histological features included tubular, tubulocystic, polypoid and/or papillary. Immunohistochemistry for NA was positive for AMACR, AE1/AE3, PAX2, PAX8, CK7, vimentin and CD10. The negative immunostain for NA included P63, PSA and CEA.

NA is a rare and easily misdiagnosed lesion. Careful histological examination is essential to accurately identify this lesion. A panel composed of AMACR (P504S), PAX8/PAX2, CK7, P63, PSA and CEA appears to be sensitive and specific in differentiating NA from its mimics of urothelial and prostatic origins.