[Nephrogenic adenoma arising from an urethral diverticulum in a female. Report of a case and review of the literature].

Nephrogenic adenoma is a benign epithelial tumour localised at the level of the urothelium and caused by metaplasia of the urothelium following prolonged aggressive stimulation over time, for example trauma or chronic urinary infection. Even a diverticulum, in whatever site it is localised, is subject to an increased risk of neoplastic transformation of the urothelium. It above all affects male subjects, with a male/female ratio of 3:1 over the age of 20, which is inverted in younger subjects. The most frequently affected site is the vescical trigonum in 72% of cases, followed by the pelvic tract of the ureter (19%) and urethra. The majority of patients is asymptomatic or reports aspecific symptoms: the most frequent picture is macroscopic hematuria, owing to the rich vascularisation of the tumour. This is followed by irritative type signs such as pollakiuria, strangury, posturination dripping and sometimes painful tenesmus. Differential diagnosis is necessary for pale cell adenocarcinoma, parauretral cysts and Gartner duct's cysts which may be associated with urethral diverticulum, localised on the bottom, and rarely symptomatic. Diagnosis is based on retrograde urethrography, cystography and endoscopic tests, with biopsy if necessary. NMR provides further details regarding the site, localisation and benign or malignant nature of the lesion. Treatment is surgical: endoscopic (transurethral) if the dimension are limited, or traditional using a suprapubic or transvaginal route if it is associated with diverticulum. Prognosis is discrete and depends on the timeliness with which the factors predisposing metaplasia are eliminated.