Incidentally Discovered Inverted Papilloma of the Urinary Bladder in Patients with Lower Urinary Tract Symptoms

Background and Purpose: Inverted urothelial papilloma (IP) is an uncommon urothelial neoplasm. We aimed to determine the clinicopathologic characteristics of IP of the bladder and its association with prostate volume and lower urinary tract symptoms (LUTS). Patients and Methods: From 1994 to 2008, 53 patients with urinary IP underwent transurethral resection of the bladder tumor (TURBT) at our institution. We reviewed the clinicopathologic characteristics of IP of the bladder and its association with prostate volume and LUTS. Results: The patient population consisted of 46 men and 7 women with a mean age of 56 years (male to female ratio 6.6:1). The most common presenting symptom was LUTS (33 men and 3 women). Of the 33 men with LUTS, the mean prostate volume before TURBT was 48.1 cc (range 21.8-109.3 cc). IP was found incidentally in 14 men on transrectal ultrasonography (TRUS) and in 2 men during transurethral prostate resection. In IP located on the bladder neck of patients with benign prostatic hyperplasia (BPH), significantly higher obstructive symptoms and larger prostate volumes than that of other located IP with BPH were observed. Conclusions: This is the largest series of cases of urinary bladder IP reported from Korea. Despite the absence of agreement of its etiology, its presenting symptoms were related to LUTS and benign prostatic enlargement. TRUS may be helpful, especially in unresponsive patients with LUTS despite medical treatment.