[Pseudodiverticula of the ureter: a precancerous lesion?]

Ureteral diverticula belong to the group of acquired diverticula even though their pathogenesis and clinical significance are still debated. They are occasionally detected during urography or retrograde pyelography and appear as small spicular or saccate wall outpouchings, single or more often multiple, mostly limited to the upper third of the ureter. The frequent association of these lesions with transitional cell carcinoma of the urinary tract is a problem of great clinical interest since they might represent a preneoplastic manifestation. The authors report on 16 patients with pseudodiverticula, 6 of whom (37.5%) affected with benign prostatic hyperplasia, 4 (25%) with synchronous or metachronous vesical neoplasm and 3 with renal stones. The remaining three patients were affected respectively with vesicoureteral reflux, neurogenic bladder and ureteropelvic junction obstruction. All patients were men over 46 years old. Ureteral involvement was bilateral in 50% of patients. The radiologic pattern consisted of small marginal outpouchings 1-3 mm in diameter, whose demonstration requires good contrast opacification and ureter distension. Pseudodiverticula were always localized in the upper third of the ureter and were multiple in 15/16 cases. Anatomical-histologic studies showed that pseudodiverticula result from hyperplastic-type proliferation of lung epithelium in the ureteral submucosa. Our observations do not confirm literature data on the frequent association between pseudodiverticula and transitional cell carcinoma because of the common presence, in our patients, of other non-neoplastic urinary conditions. The patients with benign hyperplasia of the ureteral epithelium cannot be excluded to be a risk group for cancer, even though no precise confirmation exists. The best advice is to carefully follow-up the patients with ureteral pseudodiverticula, clinically and with IVP.