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