Immunohistochemical expression of CK20, p53, and Ki-67 as objective markers of urothelial dysplasia.

Urothelial dysplasia and carcinoma in situ (CIS) are related to recurrence and progression of urothelial carcinoma. Distinguishing CIS and dysplasia from reactive atypia is often difficult on the basis of histological features alone. Cytokeratin 20 (CK20), p53, and Ki-67 are related either to neoplastic change or prognosis in urothelial proliferations. The objective of the present study was to establish the immunohistochemical pattern of these three antibodies in urothelial dysplasia and CIS. Three groups of patients were evaluated: 40 nonneoplastic urothelial samples, 50 cases with histologically incontrovertible CIS, and 30 samples with nonconclusive atypical changes (atypia of unknown significance). Monoclonal antibodies (MoAb) against CK20, p53, and Ki-67 (MIB-1) were used on paraffin-embedded samples. Nonneoplastic urothelium showed no reactivity to CK20 except for umbrella cells; p53 and Ki-67 were negative or weakly positive in <10% of basal cells. In the CIS group, 42% showed positivity for all three MoAb; 44%, for two; and 14%, only for one. CK20 was positive through the full thickness of the urothelium in 72% of cases, p53 was positive in 80% of cases, and Ki-67, in 94% of cases. In the third group, the suspected dysplastic cells showed strong positivity in scattered cells through the epithelium in 75% of cases. Aberrant CK20 expression in urothelial cells plus overexpression of p53 and Ki-67 are indicators of dysplastic change in urothelial mucosa. Thus, immunohistochemistry is a useful tool to confirm the diagnosis of CIS and could be helpful to distinguish dysplastic changes from reactive atypia.     

Prognostic significance of atypical papillary urothelial hyperplasia

Typical papillary hyperplasia, a recently recognized precursor lesion to low-grade papillary urothelial neoplasms, consists of undulating folds of cytologically benign urothelium. Well-developed, branching fibrovascular cores of a papillary neoplasm are not evident. We have noted lesions with the architectural pattern of papillary hyperplasia; however, the overlying urothelium demonstrated varying degrees of cytologic atypia. We identified 15 cases of atypical papillary hyperplasia (13 males, 2 females, age 55 to 92) with overlying urothelium showing cytologic atypia. Of these cases, 8 (53%) were received in consultation. Of the 15 cases, 8 exhibited overlying flat carcinoma in situ (CIS), 4 had overlying dysplasia, and 3 were transitional between papillary hyperplasia with atypia and the earliest lesions of papillary neoplasia. Of these cases, 5 patients had multiple specimens with atypical papillary hyperplasia (range, 2 to 8) over time. Concurrent to the diagnosis of atypical papillary hyperplasia, there were 25 different urothelial lesions: CIS (n = 11), papilloma (n = 1), papillary neoplasm of low malignant potential with CIS (n = 1), high-grade papillary urothelial carcinoma (n = 10; 3 with CIS), small-cell carcinoma (n = 1), and infiltrating urothelial carcinoma (n = 1). Of 11 patients with known prior history, 2 had 12 prior urothelial neoplasms (9 low-grade papillary neoplasms, 2 papillary urothelial neoplasms of low malignant potential, and 1 high-grade papillary cancer). Of 10 patients with atypical papillary hyperplasia and a minimum of 1 year of follow-up, 9 had 19 recurrences: CIS (n = 4), papilloma (n = 1), papillary neoplasm of low malignant potential (n = 1), infiltrating urothelial carcinoma (n = 3; 1 with CIS), and high-grade papillary urothelial carcinoma (n = 10; 5 with invasion and 2 with CIS). Whether the papillary hyperplasia had overlying CIS or dysplasia did not affect the correlation with urothelial neoplasms. Immunohistochemical analysis of p53 and Ki-67 expression in 8 cases demonstrated overexpression of p53 (n = 2; 1 with overlying dysplasia and 1 with overlying CIS), and Ki-67 (n = 5; 2 with overlying dysplasia and 3 with overlying CIS). Taken together, these results suggest that atypical papillary hyperplasia is most frequently associated with CIS and high-grade papillary cancer. In some cases, CIS or dysplasia may evolve into atypical papillary hyperplasia, with further progression to high-grade papillary cancer. This process may be analogous to papillary hyperplasia without cytologic atypia progressing to low-grade papillary urothelial neoplasms.     

Atypia in inverted urothelial papillomas: pathology and prognostic significance

Inverted papillomas of the bladder are considered benign urothelial neoplasms, based on their histology and clinical course. There are scant data on inverted papillomas with atypical features. Whether to designate them as inverted papillomas with atypia or low-grade transitional cell carcinomas with inverted features is controversial. In the present study, 11 cases of inverted papillomas with atypia and 10 controls of classic inverted papillomas without atypia were collected from 2 institutions. The inverted papillomas with atypia had the typical architectural features of inverted papillomas consisting of thin anastomosing trabeculae of urothelium growing downward into the stroma without an exophytic papillary component. The atypical areas in the current series were focal, with other areas exhibiting the benign cytology of classic inverted papillomas. Cases with atypia were subdivided into the following groups: (1) 5 cases notable for areas containing prominent nucleoli, (2) 2 cases with foci with atypical squamous features, (3) 2 cases with areas of dysplasia, approaching the level of carcinoma in situ, (4) 1 case with degenerative-appearing multinucleated giant cells, and (5) 1 case notable for nests of atypical squamous cells associated with large, atypical squamoid cells with a pagetoid appearance in addition to degenerative-appearing multinucleated giant cells. Ki67 was slightly increased in 1 case, with focal dysplasia approaching carcinoma in situ and in 1 case with prominent nucleoli (increased Ki67 in both the atypical and non-atypical areas) and in the case with atypical squamous, pagetoid, and giant cells (no increased Ki67 in the atypical components). Two of the atypical inverted papilloma cases with prominent nucleoli demonstrated an increase in p53 staining throughout the lesions. Cytokeratin (CK) 20 staining was negative in all cases of inverted papillomas. No significant increase in Ki67 staining was found in any of the 10 control cases; increased p53 staining was seen in 1 control case. CK20 staining was negative in the 10 control cases. In the 11 cases with atypia, clinical follow-up revealed no history of prior or subsequent bladder neoplasms. In the cases reviewed, most inverted papillomas with atypia did not demonstrate significantly increased cellular proliferation in comparison with inverted papillomas without atypical features. To date, there has been no association with urothelial carcinoma in the individuals diagnosed with atypical inverted papillomas. These findings suggest that these lesions are currently best classified as inverted papillomas with atypia, not as low-grade transitional carcinomas, and that they merit continued evaluation as a distinct group.     

Correlation of Ki-67 and p53 with the new World Health Organization/International Society of Urological Pathology Classification System for Urothelial Neoplasia

OBJECTIVE: The present study examines p53 and Ki-67 staining patterns of the diagnostic entities included within the new World Health Organization/International Society of Urological Pathology (WHO/ISUP) classification of urothelial neoplasms. DESIGN: We retrospectively studied 151 bladder biopsies from 81 patients with the following neoplasms: normal urothelium (n = 34 biopsies); low-grade intraurothelial neoplasia (LGIUN; n = 19); high-grade intraurothelial neoplasia (HGIUN; n = 20); papillary hyperplasia (n = 4); papilloma (n = 3); papillary neoplasm of low malignant potential (LMP; n = 12); low-grade papillary carcinoma (n = 28); and high-grade papillary carcinoma (n = 31). Sections were labeled immunohistochemically with antibodies to p53 and Ki-67 (MIB-1). Two hundred cells from each lesion were visually counted, and the percentage of positive cells was tabulated without knowledge of the WHO/ISUP diagnosis. RESULTS: In flat lesions, p53 positivity was of limited diagnostic utility; the marker was present in 6 of 34 benign biopsies, 6 of 19 LGIUNs, and 10 of 20 HGIUNs. In one case in which HGIUN was present elsewhere in the bladder, 29% of the benign urothelial cells were p53 positive. In papillary lesions, p53 positivity was not seen in 4 of 4 cases of papillary hyperplasia, 3 of 3 papillomas, and 8 of 12 LMP tumors. In contrast, p53 was detected in 18 of 28 low-grade and 26 of 31 high-grade papillary urothelial carcinomas. A p53 labeling index (LI) greater than 30% was only seen in HGIUNs and high-grade papillary carcinomas. In flat lesions, an increased Ki-67 LI separated out benign urothelium (mean LI, 0.62%) from dysplasia (mean LI, 3.3%) and HGIUN (mean LI, 11.6%). In papillary lesions, Ki-67 positivity was as follows: papillary hyperplasia (mean LI, 1.1%); papilloma (mean LI, 4.3%); LMP tumors (mean LI, 2.5%), low-grade papillary carcinoma (mean LI, 7.3%); and high-grade carcinoma (mean LI, 15.7%). A Ki-67 LI greater than 10% was seen only in low- and high-grade papillary carcinomas, HGIUN, and single cases of LGIUN and papillary neoplasm of LMP. CONCLUSIONS: An increased proliferative index as demonstrated by immunohistochemical staining for Ki-67 (MIB-1) is most often seen in papillary carcinoma and HGIUN. Marked p53 positivity is also characteristic of carcinoma but may be seen in benign-appearing urothelium, suggesting a "field effect" with occult molecular aberration.     

Usefulness of endoscopic biopsy using immunostaining of p53 and Ki-67 in tumors of the ampulla of Vater

We investigated the diagnostic and prognostic value of p53 expression and proliferative activity, as indicated by the Ki-67, in endoscopic biopsy specimens. Specimens were immunologically stained with p53 and MIB-1 (Ki-67), and the MIB-1/Ki-67 labeling index (LI) was calculated. Classification of adenomas was based on findings of H&E-stained preparations into those with low- or high-grade atypia. Well-differentiated tubular and papillary adenocarcinomas were classified as carcinomas with low- or high-grade atypia. There were significant differences among the control and adenoma patients in MIB-1/Ki-67 LI (P < 0.05). No significant difference was identified between adenomas with high grade atypia and carcinomas with low grade atypia. The p53 expression was negative in all adenomas, but it was positive in 68.2% of carcinomas. The current study demonstrated that p53 protein expression in endoscopic biopsy specimens was of preoperative diagnostic value for carcinoma of the ampulla of Vater. The p53 protein positive tumors had a relatively higher malignant potential than p53 protein negative ones. The MIB-1/Ki-67 LI was useful in differentiating non-tumorous lesions from adenomas and adenomas with low- or high-grade atypia. The MIB-1/Ki-67 LI had a prognostic value because clinicopathological factors of carcinoma of ampulla of Vater correlated with MIB-1/Ki-67 LI.     

Cytokeratin 20 and Ki-67 to distinguish carcinoma in situ from flat non-neoplastic urothelium.

Urothelial carcinoma in situ (CIS) is a high-grade neoplasm and an indicator of recurrence and progression that requires specific treatment. The distinction of CIS from flat non-neoplastic urothelium, in particular dysplasia, on the basis of histologic features is often difficult, and this study aims to validate cytokeratin 20 (CK20) and Ki-67 as discriminatory markers for this purpose. Immunostaining of these markers was applied to 26 cases of CIS, 14 atypia of unknown significance, 4 dysplasia, 6 normal, and 9 hyperplastic urothelium. CIS showed CK20 staining of deep urothelial cells in 23/26 CIS compared with restricted staining in surface cells in all non-neoplastic lesions. CIS had significantly increased Ki-67 index with a mean of 53.37% compared with that of non-neoplastic urothelium, which was <10% (P<0.0001). The proliferating cells were distributed randomly in CIS, whereas in non-neoplastic urothelium, staining was confined to the basal layer. Among the cases of atypia, 3/14 displayed deep staining for CK20 and 6/14 had elevated Ki-67 counts. In dysplasia similar findings were present in 1/4 and 2/4 cases, respectively. These findings suggest that CK20 and Ki-67 are objective markers to distinguish CIS from non-neoplastic urothelium. In cases of "atypia of unknown significance" and "dysplasia," positivity for both markers should raise the possibility of CIS or preneoplastic change and identify those cases for follow-up.     

Utility of cytokeratin 20 and Ki-67 as markers of urothelial dysplasia

Reactive urothelial atypia (RUA) can be difficult to differentiate from dysplastic urothelium. The goal was to evaluate the efficacy of cytokeratin 20 (CK20), Ki-67 and E-cadherin (E-Cad) in this regard. Fifty carcinoma in situ (CIS) cases, 50 non-neoplastic urothelia (25 normal, 25 reactive urothelial atypia (RUA)) and 17 atypia of unknown significance (AUS) cases were evaluated. All cases were stained with monoclonal antibodies against Ki-67, CK20 and E-Cad. All (100%) normal urothelia showed normal staining patterns. In the CIS group, 86%, 82% and 20% of cases showed abnormal expression with CK20, Ki-67 and E-Cad, respectively. Both Ki-67 and CK20 were positive in 68% of cases. In the RUA group, 96%, 72% and 100% of cases showed normal expression patterns with CK20, Ki-67 and E-Cad, respectively. Of 28% RUA cases with increased Ki-67, none demonstrated abnormal CK20 or E-Cad expression. In the AUS group, 47% demonstrated abnormal CK20 and increased Ki-67 expression, suggestive of urothelial dysplasia/CIS, 29% were negative with both, suggestive of RUA, and the remaining 24% cases could not be resolved. In summary, abnormal CK20 is a useful adjunct to morphology for confirming dysplasia. Ki-67 by itself is a less reliable marker of dysplasia. E-Cad is not a useful marker in this setting.     

The pagetoid variant of bladder urothelial carcinoma in situ A clinicopathological study of 11 cases

Pagetoid urothelial carcinoma in situ (CIS) is a rare variant of bladder cancer that is characterized by an intraepithelial proliferation of large cells arranged singly or in clusters and randomly distributed. These neoplasms deserve recognition and attention, chiefly because they may be overlooked or misdiagnosed as urothelial dysplasia, then causing unsuspected tumor recurrence after surgery. We report on the clinicopathological features and immunohistochemical findings of 11 (14.86%) cases of pagetoid CIS in a retrospective study of 74 cases of conventional carcinoma in situ. Most patients were male ( n=10). Their ages ranged from 31 years to 78 years. The lesion can be present with primary ( n=2) or secondary ( n=9) CIS. Pagetoid CIS is usually a focal lesion occurring in a clinical and histological setting of conventional CIS, and these patients essentially have the same progression and survival rates as patients without pagetoid changes and are treated in the same way. In cases with extensive urothelial denudation, pagetoid CIS may be focally present in otherwise normal-looking urothelium, thus alerting the pathologist to search for additional CIS elsewhere in the bladder. Given that primary extramammary Paget disease of the external genitalia and of the anal canal may extend to the bladder and, conversely, some bladder cases of pagetoid CIS may extend to the urethra, ureter, and beyond to the external genitalia, the differential diagnoses between these two entities represent an important therapeutic consideration. Our data suggest that a panel of immunostains including CK7+/CK20+/TM+ may assist in differentiating urothelial pagetoid CIS from extramammary Paget disease which is known to be CK7+/CK20-.     

Molecular pathology of non-invasive urothelial carcinomas (part I)

An international consultation on the diagnosis of non-invasive urothelial neoplasms was held in Ancona, Italy in May 2001. Besides histology and problems of classification, one group of experts (Committee no. 3) discussed the molecular pathology and cytometry of non-invasive urothelial carcinomas. In the following first part, special immunohistochemical and molecular markers for stratifications in bladder cancer were discussed including different cytokeratins (clone 34betaE12, CK 20), cell proliferation markers (Ki67/MIB-1, PCNA, AgNOR, DNA-cytometry), tumor suppressor genes and oncogenes (p53, p21, erb-B2, bcl-2), different receptor expressions of epidermal growth factor and vascular endothelial growth factor and others. These molecular markers were analyzed in diagnosis of urothelial carcinomas, recurrences, progression and response to treatment.     

Association between the expression pattern of p16, pRb and p53 and the response to intravesical bacillus Calmette-Guerin therapy in patients with urothelial carcinoma in situ of the urinary bladder

There is limited data regarding the association between the expression of cell cycle-regulating molecules and the response of patients with urothelial carcinoma in situ (CIS) to bacillus Calmette-Guerin (BCG) therapy. To examine the relationship between p16, pRb and p53 expression in bladder CIS and patient response to initial BCG therapy, we performed immunohistochemical studies for 27 patients with bladder CIS. Overexpression of p16, pRb, and p53 was observed in 37%, 41%, and 48% of patients, respectively. Initial BCG therapy was effective in 21 patients (78%). Coexistence of papillary urothelial carcinoma, depth (pTa or pT1) and grade of coexisting papillary carcinoma did not affect the response to BCG therapy. pRb overexpression had a significant relationship to poor response to BCG therapy (P= 0.027). The results of this study indicate that overexpression of pRb in bladder CIS predicts poor response of intravesical BCG instillation and status of p16 and p53 may not be predictive of initial BCG failure.     

Comparison of computerized analysis of nuclear DNA changes in uterine cervix dysplasia and in urothelial non-invasive papillary carcinoma

The nuclear DNA content was measured in preneoplastic lesions of the uterine cervix and in papillary carcinomas of the bladder. Three groups of features were calculated from the raw data: basic DNA, DNA deviation and DNA distribution. The basic DNA features, concerning both the cervix and the bladder, showed a progressive increase in the mean DNA content, a decrease in the percentage of diploid nuclei and steadily increasing values of polyploid and aneuploid nuclei. Among the DNA deviation features, the malignancy grade value was zero in the normal cervical epithelium and in the normal urothelium. An increase in this value was evident in moderate dysplasia and in urothelial papillary carcinoma of grade 2, the highest value being in CIS and in grade 3. Concerning the DNA distribution features, the values of the 15th and 95th percentiles and their difference were progressively higher both in the cervix and in the bladder, expressing a continuous shift and spread of the DNA content measurements in the different diagnostic categories, with respect to normal epithelium and urothelium. The statistical analysis showed that the strongest correlation is between 2c D.I. and % of polyploid nuclei in the cervix and between M.I. and % of aneuploid nuclei greater than 4c in the bladder. In the cervix the most discriminating feature is the Malignancy Grade, whereas in the bladder it is the percentage of diploid nuclei. The comparison between the results of the three groups of features showed that: 1) Mild dysplasia of the cervix and urothelial papillary carcinoma of grade 1 showed similar changes in DNA features. Both were basically characterized by increased proliferative activity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immunophenotype of high-grade prostatic adenocarcinoma and urothelial carcinoma.

Morphologic features alone can usually be used to distinguish prostatic adenocarcinoma and urothelial carcinoma of the urinary bladder. Poorly differentiated tumors, however, can occasionally have features of both neoplasms, making determination of site of origin difficult. No study has provided a panel of antibodies to assist in the distinction of these two tumors. For this study, 73 examples of moderately and poorly differentiated prostatic adenocarcinoma and 46 examples of high-grade urothelial carcinoma were obtained from radical resection specimens. Immunohistochemical studies were performed using the following panel of antibodies: cytokeratin (CK) 7, CK 20, 34betaE12, Leu M1, carcinoembryonic antigen (CEA)m, CEAp, p53, Leu 7, prostate-specific acid phosphatase (PSAP), prostate-specific antigen (PSA), and B72.3. Mucicarmine was also performed. Intermediate and high-grade prostatic carcinoma were compared and then high-grade prostatic carcinoma was compared with high-grade urothelial carcinoma. PSA and PSAP each stained 94% of prostatic adenocarcinomas, but no urothelial carcinomas. Leu 7 stained 94% of prostate and 17% of urothelial carcinomas. Over half of the urothelial carcinomas showed positivity for 34betaE12 (65%), as did two cases of prostatic carcinoma (6%). Eighty-three percent of urothelial carcinomas and 12% of prostatic adenocarcinomas stained with CK 7. Forty-one percent of urothelial carcinomas and 12% of prostatic carcinomas were reactive for CEAm, and p53 stained 33% and 3% of urothelial and prostatic adenocarcinomas, respectively. No significant difference was seen in the expression of CEAp, CK 20, B72.3, Leu M1, or mucicarmine between prostate and urothelial carcinoma. We propose a panel of six antibodies to assist in the distinction of high-grade prostatic adenocarcinoma from high grade urothelial carcinoma: PSA, PSAP, 34betaE12, Leu 7, CK 7, and p53. The first three antibodies should be used initially; if results are negative, the remaining antibodies may be employed.     

Nucleolar and argyrophilic nucleolar organizer region counts in urothelial carcinomas with special emphasis on grade II tumors

Prognostic assessment of bladder carcinomas of intermediate differentiation is difficult. This study therefore investigated the prognostic values of nucleolar status and silver staining of argyrophilic nucleolar organizer regions (AgNORs) in grade II bladder carcinomas. In biopsies from 34 grade II transitional cell carcinomas of the urinary bladder the number of nuclei with nucleoli, the location of nucleoli within the nucleus and the number of AgNORs were determined in 1000 or 200 nuclei per section respectively. Ten biopsies showing normal urothelium, 18 cases with mild to severe atypia, 27 grade I, 34 grade II and 12 grade III transitional cell carcinomas were also studied. Significantly differing nucleolar and AgNOR values were found comparing normal urothelium/grade I carcinomas with severe urothelial atypia/grade III carcinomas. Grade II carcinomas, however, were inhomogeneous. One subgroup had nucleolar and AgNOR values resembling grade I carcinomas while the second group had values similar to those of grade III carcinomas. This subdivision of grade II carcinomas correlates with results reported for DNA-cytometry. The results suggest a subdivision of patients with grade II transitional cell carcinomas into a low risk and high risk group.     

Neuerungen in der histologischen WHO-Klassifikation urothelialer Harnblasentumoren und abnormer flacher Urothelläsionen

Recently the World Health Organization published a new classification of urinary bladder tumors which is intended to take into account better the biology of the various lesions and to better distinguish between clearly benign and malignant lesions. We examine the possible diagnostic and clinical impact of the new classification, including recent immunohistochemical findings. Papillary urothelial lesions include papillomas, papillary neoplasms of low malignant potential, and papillary carcinomas. Flat urothelial lesions include hyperplasia, reactive atypia/atypia of unknown significance, dysplasia, and carcinoma in situ. Invasive patterns of papillary carcinomas are discussed, with special emphasis on lamina muscularis mucosae substaging. The most important feature of the new classification is its differentiation of two types of low-grade, noninvasive papillary urothelial lesions: papillary neoplasm of low malignant potential vs. papillary carcinoma. Long-term follow-up studies are needed to determine the clinical significance of this differentiation.     

Proliferative pattern of exophytic and superficially invasive and noninvasive low-grade urothelial carcinomas

In urothelial low-grade carcinomas of the bladder stage pT1, prognosis in general is good. In a subset of these tumors infiltrating beyond the lamina muscularis mucosae, prognosis clearly worsens. Unfortunately, evaluation of the lamina muscularis mucosae often is very difficult or even impossible because of its incomplete extension. In an immunohistochemical study on 131 pTa and pT1 urothelial tumors without provable lamina muscularis mucosae, we evaluated the proliferative activity with the monoclonal antibody MIB-1 and the expression pattern of cytokeratins of high molecular weight with the monoclonal antibody 34betaE12. The highest proliferative indices were found in tumors with a diffuse expression pattern of MIB-1 and 34betaE12. A preliminary analysis of follow-up data showed that 70.6% of the pT1 GIb-GIa tumors that recurred showed a diffuse expression pattern for both markers. Whether these patients are candidates for a doser follow-up or even for a more radical therapy has to be subject to further follow-up studies.     

Immunohistochemical expression of p63, p53 and MIB-1 in urinary bladder carcinoma. A tissue microarray study of 158 cases

P63 is a member of the p53 family, which plays a role in the differentiation of urothelium and is supposed to play a role in urothelial carcinogenesis. P53 and MIB-1 are recognised in many studies as predictive markers of progression, but few studies in the literature have examined p63. The aims of our study were to explore the expression of p63 in bladder carcinomas and to compare this expression to p53 and MIB-1, as well as to stage and grade. Tissue microarrays were performed on 158 urothelial carcinomas (56 pTa, 45 pT1 and 57≥pT2). Immunohistochemical studies were performed with p63, p53 and MIB-1 antibodies. In our study we observed that p63 immunostaining is present in all cell layers in papillary urothelial neoplasm of low malignant potential (PUNLMP), but partially lost in non-invasive papillary urothelial carcinoma low grade (NILGC) and in pT1/≥pT2 bladder cancers. P53 and MIB-1 displayed lower expression in PUNLMP/NILGC vs non-invasive papillary urothelial carcinoma high grade (NIHGC)/pT1, but there was no correlation between the expression of p63, p53 and MIB-1. Our study demonstrates that p63 expression distinguishes between PUNLMP/NILGC and NIHGC/pT1 (p=4.10⁵). A statistical difference disserving pTa and pT1/≥pT2 with a statistical significance (p<10⁻⁶) could also be observed. P63 should be considered as an additional biomarker that might help pathologists to classify their patients.     

Non‐urothelial carcinomas of the bladder

Non‐urothelial carcinomas involving the bladder are uncommon and often diagnostically challenging. These carcinomas may show squamous, adenocarcinomatous or neuroendocrine features, with immunohistochemical stains aiding the diagnosis in only a subset of cases. The clinical history in non‐urothelial bladder carcinomas is important, given that the differential diagnosis often includes secondary involvement of the bladder by direct extension or metastasis from carcinomas at other sites. This paper will review non‐urothelial carcinomas in each of these three morphological categories, emphasising recent changes in diagnostic grouping and challenges in the histopathological diagnosis. Review of bladder cancers with squamous morphology will include discussion of conventional squamous cell carcinoma and verrucous carcinoma and their distinction from urothelial carcinoma with extensive squamous differentiation. Bladder carcinomas with adenocarcinomatous change will include primary bladder adenocarcinoma, urachal adenocarcinoma and tumours of Müllerian type. Finally, neuroendocrine neoplasms of the bladder, including well‐differentiated neuroendocrine tumour and neuroendocrine carcinomas, will be discussed. Associated surface findings, risk factors and prognostic features will be described.     

The role of immunohistochemistry in the diagnosis of flat urothelial lesions: a study using CK20, CK5/6, P53, Cd138, and Her2/Neu

Although differentiating reactive urothelial atypia from urothelial carcinoma in situ (CIS) relies primarily on histologic evaluation, confirming the morphologic impression using immunohistochemistry (IHC) has been increasingly used in routine clinical practice. The aims of this study are to confirm the utility of commonly used markers (CK20, P53) and to test the performance of CK5/6, CD138, and Her2/Neu in the diagnosis of CIS. Using a tissue microarray comprising 52 cases of normal/reactive urothelium and 45 cases of CIS, the IHC evaluation of 5 markers was undertaken. Although the individual specificity of CK20, P53, and Her2/Neu was high (94%, 90%, and 93%, respectively), their sensitivity for CIS detection was lower, with the most sensitive marker being HER2/Neu (63%). Whereas 78% of CIS shows positivity of at least 2 of those 3 markers, only 1 case of reactive urothelium shows positivity for 2 of those 3 markers. The discriminatory performance of CK5/6 and CD138 was poor. In conclusion, HER2/Neu can be added to a panel of CK20 and P53 to help differentiate reactive atypia from CIS in difficult cases. Positive staining for at least 2 of the 3 antibodies (CK20, P53, and HER2/Neu) is strongly associated with CIS. However, the histologic findings should be a primary determinant in the diagnosis of flat urothelial lesions, with IHC playing a supportive confirmatory role.     

A useful panel in proliferative urothelial lesions: an analysis of cytokeratin 20, p53, CD44 and Ki-67 antigens

Urothelium can show several pseudoneoplastic lesions. Mimic lesions diagnosis is therapeutically and prognostically critical but it is often difficult on the basis of morphology alone in bladder biopsy specimen. We studied in a retrospective way an immunohistochemical panel that helps in this differential diagnosis. The panel includes antibodies against cytokeratin 20 (CK20), CD44, Ki67 (MIB-1) e p53 and we applied it to 31 cases of non-neoplastic urothelium (26 urothelial biopsies with reactive atypia and 5 normal urothelium) and 50 cases of urothelial neoplasia where we analized the distribution of the markers over the urothelium. We obtained two different "standard" results, for neoplastic and non-neoplastic urothelium. We were able to prove that this panel is useful, non expensive tool in the differential diagnosis of urothelial proliferative lesions.     

Iatrogenic pathology of the urinary bladder

Intravesical immunotherapy, chemotherapy, and neoadjuvant systemic chemotherapy are among the most frequent therapeutic procedures to treat malignancies of the urinary bladder. These treatment modalities produce reactive morphologic changes in the urothelium that can mimic urothelial carcinoma in situ, urothelial dysplasia or true invasive urothelial neoplasia. Mitomycin C used after transurethral resection of bladder tumor to reduce recurrences, BCG intravesical immunotherapy to treat high risk non-muscle invasive bladder cancer and urothelial carcinoma in situ, and platinum-based systemic chemotherapy to improve post-cystectomy disease-specific survival some of the causes of therapy related atypia in urinary bladder. In addition, a number of systemic drugs in use to treat other systemic diseases, such as cyclophosphamide used to treat certain auto-immune disorders or hematologic malignancies, or the anesthetics ketamine increasingly used as illegal recreational drug, may produce similarly relevant atypical changes in the urothelium, and therefore, need to be differentiated from intraepithelial neoplasia. Immunohistochemical approach to reactive urothelium from CIS using CK20, p53, and CD44 may also be of utility in the pos-therapy scenario.