BERKELEY, CA (UroToday.com) - Nephrogenic adenomas represent rare benign tumors of the urinary tract that occur in patients with a history of prior urothelial injury due to urologic surgery and chronic irritation of the urinary tract. In most cases, nephrogenic adenoma are diagnosed during elective work up of the urinary tract and present as papillary lesions with suspicious cancer-like appearance. Histopathological findings typically show cuboidal, hobnail to low columnar epithelium-lined tubules, attended by plenty of granulocytes and lymphocytes, with no sign of cytologic atypia. In some rare cases of pseudo-invasive growth pattern, immunohistochemistry is required for differentiation between nephrogenic adenoma and low-grade transitional cell carcinoma of the bladder, clear cell urothelial carcinoma, urachal carcinoma, and low-grade adenocarcinoma of the prostate.
In our reported case, the authors were relieved to find out the benign nature of the tumor after the detection of the suspicious lesion had indicated to switch from endourological stone therapy to resection of the bladder tumor. Since resection of the nephrogenic adenoma, the patient has received multiple endourological interventions without recurrence of the disease at 17 month follow-up.
However, the authors wondered if a standard-of-treatment based on the available literature could be implemented for unexpected tumors in adolescent patients. Reviewing published data showed different topics of clinical relevance that led to the following approach of therapy: Unexpected detection of tumors of the urinary tract in young patients with a history of urological surgery is not necessarily a worrisome event since the diagnosis of nephrogenic adenoma at the site of prior urothelial injury is well documented. Nevertheless complete resection to ensure histological characteristics remains mandatory. Since few cases of metachronous malignancy are being published and the question of precancerous potential of nephrogenic adenoma has not been definitively answered yet, urological follow-up of the lesion, with a reported recurrence rate up to 80%, is advisable.
Written by:
René Mager as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Klinik für Urologie und Kinderurologie, Universitätsklinikum Frankfurt, Germany
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