[Nephrogenic adenoma of the bladder. Morphological and immunophenotypic study with particular attention to differential diagnosis]

Abstract

Background: Nephrogenic Adenoma (NA) is a rare lesion of the urinary tract, considered a metaplastic response to chronic inflammation, trauma or immunosuppression.

Methods and results: We report two cases of NA arising in the urinary bladder of patients with previous history of recurrent urinary tract infections due to neuropsychiatric disease. Pathological examination of the lesions, resected by transurethral (TUR) management, revealed a papillary proliferation of tubules and cysts lined by cuboidal to low-columnar cells without atypia. Immunohistochemistry showed positivity for Cam 5.2, CK7 and EMA. MIB 1 count demonstrated a positivity in 12/200 cells in case 1 and < 2/200 in case 2. No expression of nuclear p53 was evident.

Conclusion: NA is a benign unusual neoplasm which might be misdiagnosed as clear cell adenocarcinoma of the bladder or prostatic adenocarcinoma. Its recognition is important because it is a benign lesion cured by a conservative resection and no additional therapy is generally required.