Urothelial (Transitional Cell) Papilloma of the Urinary Bladder: A Clinicopathologic Study of 26 Cases

Abstract

The existence of a papillary lesion of the urinary bladder with a benign clinical course and recognizable morphologic features that merit the benign categorization "papilloma" has been controversial. The clinical aspects and histologic features of these lesions remain to be fully elucidated. We have studied the clinicopathologic features of 26 patients with urothelial papillomas and correlated them with outcome. Papillomas occurred in two distinct clinical settings: (1) de novo neoplasms (23/26) or (2) those occurring in patients with a known clinical history of bladder cancer ("secondary" papillomas; 3/26). Follow-up information was available in 14/23 of the de novo cases (mean ‫؍‬ 39 mo) and in 3/3 secondary cases (mean ‫؍‬ 24 mo). Patients with de novo papillomas had a mean age of 46 years; 16 were male and 7 were female. Twelve of 14 had a benign clinical course with no recurrences; 1 developed a recurrent papilloma at 3 years, and 1 developed a pT3a high-grade papillary urothelial carcinoma at 4 years. Patients with secondary papillomas had a mean age of 66 years; two were male and one was a female. One of these patients developed two additional recurrences, and two patients had no new recurrences. Morphologically, the papillary architecture ranged from a common simple, nonhierarchical arrangement to, infrequently, more complex anastomosing papillae with budding. The individual papillae ranged from small (most common), with scant stroma and slender fibrovascular cores, to large, with marked stromal edema and/or cystitis cystica-like urothelial invaginations. Common to all was a lining of normal-appearing urothelium without hyperplasia, maintenance of normal polarity, and frequent prominence of the umbrella cell layer. Overall, no patient with a diagnosis of papilloma died of disease; only one patient with a de novo lesion (7.0%) had a recurrent papilloma, and 1/14 (7.0%) progressed to a higher grade and stage of disease, although this patient was on immunosuppressive therapy secondary to a renal transplant. De novo urothelial papillomas occur in younger patients and usually have a benign course. Urothelial papillomas are histologically and probably biologically distinctive tumors and merit distinction from other higher risk papillary neoplasms of the urinary bladder.

Unique clinicopathologic and molecular characteristics of urinary bladder tumors in children and young adults

“…Most tumors are solitary and located near the ureteric orifices. The clinical course of these tumors is generally favorable, although some cases in adults are diagnosed with concurrent UC [40]. Papilloma sometimes recurs, although progression is not a feature.…”

“…Papilloma sometimes recurs, although progression is not a feature. In the 2003 study by McKenney and colleagues, 1 patient presented in childhood (age 8 years) and in all, 7 patients were 30 years of age or younger [40]. In another study focusing on urothelial neoplasms in patients under age 21, 2 patients (8.7%) had tumors that fit the current criteria for urothelial papilloma [3].…”

“…Patients are most often males, with a predilection of 2:1, usually adult but less than 50 years of age, who present with hematuria [39,40]. Urothelial papilloma in pediatric patients is unusual but is occasionally reported [3,40,41].…”

Mimickers and tumours in the lower urinary tract: Need for a more efficient vigilance?

“…However, a 49-year-old male, on immunosuppressive therapy for a renal transplant, developed a high-grade invasive tumour during follow-up. 9 PUNLMPs accounted for most bladder malignancies in a recent SEER review. 1 Although most pediatric tumours may be considered congenital, this is controversial.…”

In vitro assessment of potential bladder papillary neoplasm treatment with functionalized polyethyleneimine coated magnetic nanoparticles

“…1,2 The treatment typically involves transurethral resection followed by intravesical therapy, where chemotherapeutic agents are administered directly into the bladder. 3 Despite obvious advantages of local delivery, intravesical therapy has its limitations and is thus an important area for further development, 4 in which nanoparticles (NPs) proved to be a promising strategy for improvement.…”