Inverted papilloma of bladder

IS SURVEILLANCE NECESSARY FOR INVERTED PAPILLOMA IN THE URINARY BLADDER AND URETHRA?

BACKGROUND

A case series of inverted papilloma of the urinary bladder and urethra is presented, together with a review of the literature with respect to multiplicity, recurrence rate and association with transitional cell carcinoma, and a discussion on surveillance of the lesion.

METHODS

Cases of inverted papilloma of the lower urinary tract in a single centre were reviewed. Patient and tumour characteristics, recurrence and associated transitional cell carcinoma are reported.

RESULTS

Twenty patients were included (18 male, two female). The mean age was 60.8 years (range 35-78 years). All had solitary tumours ranging from 3 mm to 30 mm in size. Median cystoscopic follow up was 30 months (range 2-140 months). There was no recurrence. One patient was associated with subsequent transitional cell carcinoma 44 and 76 months later. Together with the present 20 cases, review of the English literature with respect to inverted papilloma of the lower urinary tract identified a total of 322 cases reported, with a recurrence rate of 3.85%. Moreover, 1.55%, 5.90% and 1.54% were associated with previous, simultaneous and subsequent transitional cell carcinoma, respectively.

CONCLUSIONS

Recurrence is not uncommon and risk of subsequent transitional cell carcinoma is not rare, such that non-invasive surveillance with flexible cystoscopy is recommended for inverted papilloma of the lower urinary tract.

Multiple simultaneous inverted papillomas of the upper urinary tract. A case report with a review of ureteral and renal pelvic inverted papillomas

An asymptomatic 73-year-old woman was found to have multiple, simultaneous, inverted papillomas of the renal pelvis and ureter. A review of the world literature yielded 34 cases of inverted papillomas in the upper urinary tract: 13 in the renal pelvis, and 21 in the ureter. Among these 34 cases, there were 26 male and five female patients, with gender not given for three others. Patients ranged in age from 19 to 89 years (mean, 64.1 years). Many cases lacked complete clinical details but, among the others, gross painless hematuria was the presenting symptom in seven; hematuria with flank pain or colic in six; and pain without hematuria in six. Only six patients lacked urinary tract symptoms, and three of these had microscopic hematuria. Only two patients had more than one inverted papilloma, and these were not multicentric. Adequate pathologic documentation and follow-up data were, unfortunately, absent in many of the cases. Although inverted papillomas are curable with surgical resection, with a low rate of local recurrence, they appear to be associated with synchronous or asynchronous carcinomas, especially other transitional cell tumors in the urinary tract.

Inverted papilloma of bladder: clinical significance

Based on 15 cases of inverted urothelial papilloma, we present the clinical significance of these lesions in view of the current literature. An inverted papilloma should raise suspicion with respect to the whole urothelial surface. However, approaching every lesion of this type as a (pre-)neoplastic tumor does not seem justified, since 90 percent of all cases reported so far do not present any clinical or histologic feature of malignancy. Some factors, such as the patient's history, eventually associated urothelial carcinomas, or histologic features of malignant transformation within an inverted papilloma, must be taken into consideration. If no single indication in favor of malignancy has been disclosed, we believe follow-up with yearly endoscopic investigations, in addition to regular urine cytologies, may suffice.

Histology and histogenesis of two different types of inverted urothelial papillomas

Inverted papillomas are rare tumors of the lower urinary tract. Among 1829 reclassified tumors of the urinary bladder, renal pelves, ureters, and urethra, there were 40 (2.2%) inverted papillomas. The great majority of these were localized in the bladder. Because of distinctive histologic features and patterns of growth it is possible to differentiate between two basic types of inverted papillomas which were termed "trabecular" and "glandular." The trabecular type consists of widely branched, anastomosing cords of urothelial cells originating directly from the overlying transitional epithelium. The trabeculae are arranged horizontally or perpendicularly to the surface epithelium and occasionally exhibit peripheral palisading of the cells. The glandular type is characterized by multiple round to oval islands of proliferated urothelial cells together with pseudoglandular and true glandular structures which are often still connected with the surface urothelium. The gland-like structures are lined by stratified urothelium, the true glands by mucus secreting columnar epithelium. Sometimes glandular metaplasia of an intestinal type with goblet cell formation could be observed. Inverted papillomas of the trabecular type arise histogenetically from a proliferation of the basal cells of the urothelium. The glandular type develops apparently from a proliferative cystitis cystica and glandularis which, therefore, should be considered a potentially preneoplastic lesion. The predominant view of the biological behavior of inverted papillomas is that of a benign neoplastic lesion. Morphologic findings supplied some arguments in favor of a low grade malignant potential of these tumors. However, their malignant transformation seemed to be much lower than that of exophytic papillomas.

Inverted papilloma of the urinary tract

We report 9 clinicopathological cases of inverted papilloma. The occurrence of associated true malignant epithelial tumors in the urinary tract in 4 patients is not concurrent with previous reports. Even though inverted papilloma per se is a benign lesion it may be associated with malignant epithelial tumors of the urinary tract. The similarity between proliferative lesions of the bladder and inverted papilloma is discussed. The possibility of common etiologic factors of proliferative cystitis, cystitis cystica, cystitis glandularis, inverted papilloma and ordinary bladder tumors may be considered.

Inverted papilloma of urinary tract

The inverted papilloma of the urinary tract is a rare tumor; few urologists and pathologists are aware of its existence. Even if the histogenesis of the lesion is unknown, the correct diagnosis is essential, since its behavior appears totally benign, contrary to transitional cell carcinoma. We report 3 new cases, one originating in the renal pelvis, and one in an eighteen-year-old woman.

Lobulated inverted papilloma of the ureter

An inverted papilloma of the ureter with ipsilateral hydronephrosis was found in a 77-year-old man who had a history of prostatic carcinoma. Inverted papilloma of the urothelium is a rare lesion, with the vast majority of cases being found in the bladder. To date none has been documented in the ureter.

Inverted papilloma and papillary transitional cell carcinoma of urinary bladder: report of four cases of inverted papilloma, one showing papillary malignant transformation and review of the literature

Four new cases of inverted urothelial papillomas are described and added to the 47 cases previously reported in the literature. Three papillomas present benign gross and microscopic characteristics. The fourth case, however, demonstrates inverted papilloma and papillary transitional cell carcinoma in a single polypoid lesion. This papillary malignant transformation, not previously observed in inverted papillomas, cautions against overconfidence in benign nature of inverted papilloma.

Inverted papilloma of the bladder: a distinct urological lesion

With the addition of six new cases, 104 cases of inverted papilloma of the bladder are reviewed. Pathological and epidemiological characteristics of this distinct bladder lesion are outlined, comparison with transitional cell papilloma is investigated, and recommended therapy and follow-up are offered.

Inverted papilloma of the lower urinary tract

A study of 35 cases of inverted papilloma of urothelium confirms that it is a distinctive entity and typically benign. These lesions occur mainly in males, may be multiple, and are sometimes situated elsewhere than in or near the trigone, which is their characteristic site. Their precise histogenesis remains uncertain. It must be stressed that not all transitional cell tumours of inverted pattern are of this type; some will have the appearance of and behave as malignant tumours. The same diagnostic criteria of malignancy established for the more common exophytic papillary neoplasms must be applied also to the inverted papillary tumours herein described.