Inverted papilloma of the urinary tract.

OBJECTIVES: • To compare the clinical and pathological details of inverted papilloma (IP) of the urinary tract diagnosed in Western Australia with those published. • To determine whether urinary tract IP requires post-treatment cystoscopic follow-up.

PATIENTS AND METHODS: • Clinical and pathological details were summarized for 41 cases of IP of the urinary tract diagnosed in Western Australia between 1998 and 2010. • Publications on IP of the urinary tract were reviewed and summarized.

RESULTS: • IP of the urinary tract is a rare benign tumour most commonly diagnosed in older men presenting with haematuria or symptoms of lower urinary tract obstruction. • IP is most frequently identified in the bladder neck or trigone as a polypoid growth with a smooth surface. • The major differential diagnosis is transitional cell carcinoma (TCC) with an inverted growth pattern, with differentiation based mainly on morphological criteria. • Treatment involves transurethral resection for lower urinary tract lesions whereas upper urinary tract IPs are resected by ureteroscopy, percutaneous endoscopy, partial ureterectomy or nephroureterectomy. • IP is weakly associated with a history of TCC and with increased risk of concomitant or subsequent TCC.

CONCLUSIONS: • Based on the association with TCC, post-treatment follow-up for IP of the urinary tract should include cystoscopic follow-up.