Nephrogenic adenoma - a study with special reference to clinical presentation

Objective To obtain information on the presenting symptoms, location, sex distribution, age, endoscopic appearance, histopathology, suitable treatment and recurrence of nephrogenic adenoma, a rare, benign lesion of the urinary tract mucosa. Patients and methods The records of 31 patients with nephrogenic adenoma diagnosed at the Sahlgrenska University Hospital between 1980 and 1996 were reviewed to determine the symptomatology, imaging investigations, endoscopic presentation, clinical outcome after resection and the frequency of recurrence. Results The lesions were found in the urinary bladder, bulbar urethra, urethral diverticula and the prostatic urethra. Eight patients presented with haematuria, 13 complained of urinary frequency and bladder pain and in 12 patients without subjective symptoms from the urinary tract, the lesion was found accidentally. Twenty-seven of the patients had a history of previous urothelial trauma, either by instrumentation or inflammation. Seventeen of the lesions were polypoid at endoscopy, the remainder being nat except for two cases, in which they were not noted because they were concealed in another lesion to be resected. Seven patients had one or more recurrences. All patients with symptoms responded well to transurethral resection. Conclusion Nephrogenic adenoma mimics tumour or chronic cystitis and it is rarely suspected on clinical grounds; instead, the diagnosis is almost always histological. This study supports the view that nephrogenic adenoma may represent a metaplastic response to trauma of the urothelium and that transurethral resection provides a good method of relieving the symptoms in symptomatic nephrogenic adenoma.