Purpose: This study aimed to evaluate the tumor biologic behavior and prognostic value of inverted papilloma(IP) of the urinary tract.
Materials & Methods: Thirty-one cases(27 males and 4 females, mean age 55.2 years) of urinary IP that were treated at a single center were retrospectively reviewed. There were 21 cases with bladder IP only(group 1), 8 cases with bladder IP and transitional cell carcinoma(TCC) within a single neoplasm(group 2), and 2 cases with IP and TCC in a different location(group 3). The patient and tumor characteristics were analyzed.
Results: There was a male predominance with hematuria being the main presenting symptom in all groups. The most common macroscopic feature of IP was a polypoid lesion in group 1. The most common location of IP was bladder neck(57.1%) in group 1 and lateral bladder wall(75%) in group 2. The most common associated urologic disease was benign prostatic hyperplasia in group 1. Transurethral resection was performed in 30 cases(96.8%). There were no recurrences at a mean follow-up of 19.4(3-68) months after surgery in 27 cases followed for 3 months or longer.
Conclusion: One-third of urinary IP were associated with TCC within a single neoplasm or in a different location, and this suggests that IP has a malignant potential. However, because there was no recurrence in IP of the urinary tract, a surveillance protocol as frequent as the one suggested for urothelial cancer does not seem to be necessary.