Evaluation of urinary inverted papillomas: a report of 13 cases and literature review.

Inverted papilloma (IP) of the urothelium accounts for 2.2% of urothelial neoplasms. The aim of this study was to report the results of 13 patients with urinary IP, pointing out the clinical features, presentations, treatment options and outcomes. The mean age and mean follow-up periods of the patients were 60.23 +/- 3.25 (range, 44-81) years and 30 (range, 6-42) months, respectively. There was no coexistence of urothelial carcinoma with IP at presentation. Cystoscopy showed a solitary papillary tumor in the bladders of 11 patients and solid pedunculated tumors in the remaining two patients. The site of development was the bladder in 12 cases (92%) and ureter in one (8%) case. Transurethral bladder tumor resection was performed in 12 cases. For the case with IP in the ureter, nephroureterectomy was performed. Pathologic examination demonstrated that seven of the 13 cases were of the trabecular type and six were of the glandular type. Of the 13 cases, two (7%) had recurrence, at 1 year and 1 month and 1 year and 5 months from initial resection. The male to female ratio was 5.5:1. Initial symptoms included macroscopic hematuria in five cases, microscopic hematuria in four, and dysuria and microscopic hematuria in three; one case was asymptomatic. IPs of the urinary bladder are benign tumors that can be treated successfully by transurethral resection and fulguration of the tumor bed. In addition, these lesions must be followed up closely for recurrence and malignant transformation.