Fibroepithelial polyp of the lower urinary tract in adults.

OBJECTIVE: Fibroepithelial polyps of the urinary tract are rare with most cases reported in children.

DESIGN: We report the clinicopathologic features of 12 fibroepithelial polyps of the lower urinary tract in adults.

PATIENTS: There were 9 males, 2 females, and 1 patient where the gender was unknown (median age, 44 years; range, 17-70 years).

RESULTS: Chief clinical symptoms were hematuria, urinary urgency, and hesitancy. Five patients were asymptomatic, where the lesions were discovered incidentally. Most lesions were located near the verumontanum or the bladder neck. Ten patients were treated by transurethral resection. Of the 10 patients with follow-up information, none showed recurrence (mean, 20 months; median, 17 months). Histologically, all of the fibroepithelial polyps were lined by normal-appearing urothelium, with in one lesion the additional finding of a columnar epithelial lining. There were three overall architectural patterns seen within fibroepithelial polyps. The most common pattern (Pattern 1) seen in 5 cases consisted of a polypoid mass with club-like projections resembling a cloverleaf with florid cystitis cystica et glandularis of the nonintestinal type in the stalk. The second pattern (Pattern 2) seen in 4 cases consisted of a papillary tumor composed of numerous small, rounded fibrovascular cores containing dense fibrous tissue. The last morphologic pattern (Pattern 3) consisted of a polypoid lesion with secondary tall finger-like projections, which was seen in 3 cases. All lesions lacked prominent edema and inflammation seen in polypoid cystitis. Fibroepithelial polyps contained broader stalks with dense fibrous tissue, in contrast to the thin delicate loose fibroconnective tissue seen in the stalk of papillomas. One lesion contained atypical degenerative-appearing stromal cells.

CONCLUSIONS: Although fibroepithelial polyps have been considered to be congenital, we think that some of these polyps could develop after birth because all of our patients first showed clinical symptoms in adulthood. Because fibroepithelial polyps in adults are rare, some of these cases can be misdiagnosed as urothelial neoplasms or reactive conditions. Recognition of the precise histologic features of fibroepithelial polyp can facilitate its correct diagnosis.