Inverted urothelial papilloma: report of two cases

A case of bladder-inverted papilloma after brachytherapy for prostate cancer

An 82-year-old male who presented with the chief complaint of gross hematuria and a history of prostate cancer treated with brachytherapy 6 years previously is described. Cystoscopy revealed multiple bladder tumors on the right posterior wall. A transurethral resection of the bladder tumor was performed and a pathological diagnosis of the inverted papilloma was made. To the best of our knowledge, this case is the first report of bladder-inverted papilloma after brachytherapy for prostate cancer.

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.

Inverted Papillomas of the Prostatic Urethra

Inverted papillomas of the genitourinary tract are uncommon benign neoplasms usually occurring in the urinary bladder and less frequently in the upper urinary tract. To date, there are scant data and no comprehensive studies of inverted papilloma originating in the prostatic urethra. We identified 21 cases and evaluated their demographic, clinical, and histopathologic features. Patients had a mean age of 65.1 years (range: 30 to 89 y), with 10/21 (47.6%) presenting with gross hematuria (n = 8) or irritative symptoms (n = 2) related to the inverted papilloma and 11/21 (52.4%) detected incidentally during work-up/treatment of prostate cancer (n = 6) or benign prostatic hypertrophy (BPH) (n = 5). Fourteen cystoscopically evaluated lesions measured 0.1 to 2.0 cm, and were described as polypoid (n = 9), papillary (n = 4), or an enlarged median lobe (n = 1). Lesions were diagnosed on transurethral resection (n = 8), biopsy/polypectomy targeted to the lesion (n = 6), radical prostatectomy for prostate cancer (n = 4), or biopsy unrelated to the lesion (n = 3). Histologically, 14/21 cases (67%) displayed classic inverted papilloma architecture. The remaining cases showed foci of squamous metaplasia with moderate atypia (n = 4), rare true papillary fronds in a classic inverted papilloma background (n = 2), or both (n = 1). Eleven cases with prostatic tissue revealed adenocarcinoma of the prostate [n = 6; Gleason score 6 (n = 3) or 7 (n = 3)], high-grade prostatic intraepithelial neoplasia (n = 1), benign prostatic hypertrophy (n = 3), or adenosis (n = 1). No patients had a prior history of either inverted papilloma or urothelial carcinoma, whereas 2 patients were diagnosed with high-grade urothelial carcinoma of the bladder synchronous with their inverted papilloma diagnosis. Only 1 of the 18 patients with available follow-up had a recurrence of inverted papilloma in the prostatic urethra. None of the other patients had local recurrences or recurrences at other locations in the urinary tract (mean follow-up 39.9 mo; range: 3 to 120 mo). Inverted papillomas of the prostatic urethra are benign lesions that are commonly detected incidentally and are not associated with a history of urothelial malignancy. Although urothelial carcinoma elsewhere in the genitourinary tract may occur simultaneously, malignant transformation or recurrence as a malignant lesion has not been identified in inverted papilloma of the prostatic urethra.

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.

Urethral polyp presenting as interlabial mass in young girls

We describe two young girls who presented with an interlabial mass. Histologic examination of each excised mass revealed a benign urethral polyp covered with transitional and squamous epithelium. Urethral polyps should be included in the differential diagnosis of an interlabial mass in young female patients.

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.

Papillary adenoma of the prostatic urethra

Papillary adenoma of the prostatic urethra is a common cause of hemospermia and hematuria in young men in our country. Between November 1982 and June 1983, 25 such patients have been treated. Of these patients 18 were between 19 and 29 years old, 6 were between 30 and 39 years old, and 1 was 40 years old. The lesion presents a classic histologic pattern with orderly columnar cells covering a delicate vascularized stalk and subepithelial infolding cells forming prostate-like glands. The lesion was located on the verumontanum in 5 instances (20 per cent), in the paramontanal gutter in 19 (76 per cent), and in the paramontanal gutter and at the bladder neck in 1. The lesion is believed to be completely benign, since no cases of malignant transformation have been reported to date. The suggested treatment is cautious fulguration.

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 ductal papilloma: a distinctive lesion of minor salivary gland

Four cases of inverted ductal papilloma are presented. Their origin is the excretory duct reserve cell of minor salivary gland and they appear clinically as a submucosal mass. All tumors occurred in adults and there was equal distribution between men and women. Treatment is complete surgical excision and no recurrences have been reported thus far.

Inverted papilloma of ureter

Two cases of inverted papilloma of the ureter are reported. The possible etiology and clinical significance of this previously unreported lesion are discussed.

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.

Epithelial papilloma and squamous cell carcinoma of the nasal cavity and paranasal sinuses: a clinicopathological study

Seventeen cases of intranasal epithelial tumors are reviewed. Thirteen were epithelial papillomas and four were squamous cell carcinomas associated with epithelial papillomas. In two cases followed over a 10 year period, transformation from an initial papilloma into a carcinoma was demonstrated. The histopathologic caracteristics of these lesions are described including the presence of prominent palisading and intraepithelial nesting in some tumors. The literature was reviewed for reports of carcinoma arising in previously benign epithelial papillomas. We suggest that squamous cell carcinoma may occasionally arise from a previously benign epithelial papilloma.

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.

Stages of transformation in the development of N-butyl-N-(4-hydroxybutyl)-nitrosamine-induced transitional cell carcinomas in the urinary bladder of rats

The histogenesis of papillary and nonpapillary transitional cell carcinomas were studied morphologically and autoradiographically in 177 female Wistar rats after oral application of N-butyl-N-(4-hydroxybutyl)-nitrosamine with varying exposure and induction times. By far the largest proportion of carcinomas developed by a malignant transformation of preexisting papillomas or their precursors, the papillary hyperplasias. The transition into a focally malignant growth did not take place abruptly, but occurred stepwise through different successive stages of transformation, each having its own distinct morphological character. The first stage consisted of a focal, sharpely defined cellular atypia. In a further stage carcinomata in situ developed out of the atypical foci and progressed finally in a last stage of transformation into a circumscript infiltrative growth. The successive development of each stage occurred independent of any further carcinogen application after transformation was initiated at the molecular level. The number of papillomas with transformation stages increased with a lengthening of the exposure and induction time. 74.4% of all the registered papillomas had been transformed. Consequently papillomas must be considered potentially highly malignant. The 3H-TdR index was 4.2 times higher in atypical urothelial areas (7.6%) and 7.5 times higher in carcinomata in situ (14.3%) than in the surrounding papillomatous structures which appeared light microscopically benign. The latter demonstrated a rather constant 3H-TdR index, whether they bordered on atypical foci (1.8%) or carcinomata in situ (1.9%). The length of exposure and induction time exercised no significant influence on the degree of proliferative activity. The development of transitional cell carcinomas from a primary carcinoma in situ (intraurothelial carcinoma) played a much less significant role.

Inverted papillomas of the urinary bladder

Study of 20 patients with inverted papilloma of the urinary bladder and urethra revealed that the lesion is a true neoplasm, benign in its histologic morphology and clinical behavior. The lesion is believed to arise from the trigone and bladder outlet as a result of chronic proliferative cystitis. It occurs predominantly in men who are past middle age. The most commonly associated clinical symptoms are hematuria and those of urinary obstruction. The lesion may be easily mistaken for a low-grade papillary transitional cell carcinoma, although the histologic appearance is distinctly different, as is its subsequent behavior.

Inverted papilloma of bladder

The fifth reported case of a rare variant of transitional papillary tumor of the bladder termed inverted papilloma is reported with a brief review of the literature. This tumor is likely to be confused with invasive malignant papillary carcinoma although it has adistinct histologic pattern, and it is for this reason that attention is drawn to the entity.