The many faces of urothelial carcinoma: an update with an emphasis on recently described variants

Giant cell carcinoma of the urinary bladder : Clinicopathologic analysis and oncological outcomes

We present the clinicopathological features of 23 cases of the giant cell subtype of urothelial carcinoma, a rare subtype of bladder cancer recognized in the current World Health Organization classification of urological tumors. Histologically, the architectural pattern of the tumor varied from infiltrating to the solid expansile pleomorphic tumor with giant, bizarre, anaplastic cells. Typical or atypical mitotic figures were frequently present in all cases. Between 10 and 30% of the tumor had a giant cell component. All cases were associated with conventional high-grade urothelial carcinoma, with areas of squamous cell divergent differentiation and micropapillary carcinoma present in six and two cases, respectively. In one case each had sarcomatoid, nested, small cell, or glandular divergent differentiation. At diagnosis, 35% of patients had advanced disease and 12% had distant metastases. When comparing giant cell urothelial carcinoma with conventional urothelial carcinoma in a matched analysis, differences in overall and cancer-specific survival were observed, particularly in the T1 stage category. Immunohistochemical staining showed a similar profile of urothelial lineage with frequent positive expression of uroplakin II, GATA3, CK20, CK7, and S100P in both giant cell and conventional urothelial carcinomas. High Ki67 proliferation (range, 60-90%; mean, 71%) and nuclear p53 accumulation (mutant profile; range, 50-90%; mean, 64%) were observed. Using the 22C3 assay, the expression of PD-L1 was found to be variable in two cases, and beta-HCG was negative. In conclusion, giant cell carcinoma is a subtype of urothelial carcinoma associated with advanced clinical stage and a trend to lower survival rates.

Neoadjuvant Chemotherapy Prior to Radical Cystectomy for Muscle-Invasive Bladder Cancer With Variant Histology: A Systematic Review and Meta-Analysis of Survival Outcomes and Pathological Features

PURPOSE

To conduct systematic review and meta-analysis to evaluate effects of neoadjuvant chemotherapy (NAC) on survival and histopathological outcomes of variant histology (VH) of urothelial carcinoma (UC) of bladder.

METHODS

This systematic review was registered in PROSPERO (CRD42023389115). Literature search was conducted in PubMed/Medline, Embase, and Cochrane Library for studies published up to January 2023. Population, intervention, comparator, outcome, and study design were as follows: bladder cancer patients with VH (population), neoadjuvant chemotherapy (intervention), radical cystectomy only (comparators), oncological survival and pathologic response (outcomes), and retrospective or prospective (study design).

RESULTS

Finally, a total of 17 studies were included in the present study (quantitative analysis, n = 17; qualitative analysis, n = 12). Pooled HR was 0.49 (95% CI: 0.31-0.76; P = .002) for OS. Pooled HR was 0.61 (95% CI: 0.38-0.98; P = .04) for CSS. Pooled HR was 0.44 (95% CI: 0.21-0.93; P = .03) in PFS. Pooled OR was 6.61 (95% CI: 4.50-9.73; P < .00001) in complete pathologic response. Pooled OR was 9.59 (95% CI: 3.56-25.85; P < .00001) in any pathologic response. Evidence quality assessments for each 5 comparisons using the GRADE approach were that Certainty was moderate in 1, low in 1, and very low in 3.

CONCLUSIONS

Administration of NAC before surgery in bladder cancer patients with VH might confer better survival outcomes and higher pathologic down staging rate than no administration of NAC before surgery.

Survival Analysis of Lymphoepithelioma-Like Carcinoma of the Urinary Bladder and the Effect of Surgical Treatment Modalities on Prognosis

Purpose: This study aimed to investigate the prognostic factors of patients with lymphoepithelioma-like carcinoma of the urinary bladder (LELCB) and explore the value of surgical treatment. Methods: Data of patients with LELCB were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. The multivariate analysis was performed using the stepwise Cox proportional hazards regression model and conditional inference tree method to identify significant prognosticators of overall survival (OS) from the parameters such as age, gender, lymph node involvement, tumor extent, radiation, chemotherapy, and surgery type. Literature review (LR) was performed, and eligible cases were used to validate prognostic classification using the Kaplan-Meier method with log-rank tests. Results: Sixty patients with a median age of 69.5 years were identified from the SEER database and 91 patients through LR. The Cox analysis identified age, gender, lymph node involvement, and surgical approach as independent prognosticators of OS. Based on the nomogram scores, patients were stratified into three prognostic groups: (I) patients younger than 70 years; (II) patients older than 70 years, who received bladder-sparing therapy (BST); and (III) patients older than 70 years undergoing radical cystectomy (RC). Patients in group II had the worst outcomes in terms of OS compared with patients in groups I and III (p < 0.001 and p = 0.03, respectively). A similar survival pattern was found in the LR cohort. Conclusion: The nomogram provided individualized prognostic quantification of OS in patients with LELCB. BST could yield favorable outcomes when treating LELCB, especially for younger patients, whereas older patients might derive more survival benefit from RC.

Urinary Large Cell Neuroendocrine Carcinoma: A Clinicopathologic Analysis of 22 Cases

Large cell neuroendocrine carcinoma (LCNEC) of the urinary tract is a rare disease. We present a relatively large retrospective cohort of urinary LCNEC, 20 from the urinary bladder, and 2 from the ureter, from a single institution. The patients included 16 men and 6 women with a median age of 74.5 years. Most LCNEC presented at an advanced stage with tumors invading the muscularis propria and beyond (21/22). Eight cases were pure LCNEC, while 14 cases were mixed with other histologic types, including conventional urothelial carcinoma (n=9), carcinoma in situ (n=7), small cell carcinoma (n=6), and urothelial carcinoma with glandular (n=3) features. Most LCNEC expressed neuroendocrine markers synaptophysin (22/22), chromogranin (13/16), CD56 (7/7), TTF1 (8/8), and INSM1 (2/3). They were negative for common urothelial markers including HMWCK (0/3), p40/p63 (0/6), CK20 (0/10), and had variable GATA3 staining (4/8). Ki-67 stained 25% to nearly 100% tumor cell nuclei. Patient survival was associated with cancer stage, and pure LCNEC showed worse survival than mixed LCNEC. Compared with small cell carcinoma at similar stages from a prior study, LCNEC had a worse prognosis only when patients developed metastatic disease. For organ-confined LCNEC, neoadjuvant chemotherapy followed by radical resection is the treatment option to achieve long-term survival.

Sarcomatoid Urothelial Carcinoma With Myxoid Stroma: A Case Report and Diagnostic Approach

Bladder cancer is the seventh most common cancer in the world. Urothelial carcinoma is the most common type of bladder cancer. Other subtypes like squamous cell carcinoma and adenocarcinoma are less common. Urothelial carcinoma has a propensity for divergent differentiation. Sarcomatoid carcinoma is one of the variants of urothelial carcinoma. It is an aggressive tumor that presents at an advanced stage and has a poorer prognosis than conventional urothelial carcinoma. Therefore, identifying this variant histology is important clinically. The sarcomatoid component in sarcomatoid carcinoma can be spindle cell (not otherwise specified), myxoid, pseudoangiosarcomatous, and undifferentiated sarcoma like. Myxoid stroma in sarcomatoid urothelial carcinoma has been described but reported very rarely. We present a case of sarcomatoid urothelial carcinoma with myxoid stroma along with a review of the diagnostic approach to myxoid spindle cell lesions of the urinary bladder.

Histologically confirmed distant metastatic urothelial carcinoma from the urinary bladder: a retrospective review of one institution's 20-year experience

Background

Urothelial carcinoma (UC) accounts for roughly 90% of bladder cancer, and has a high propensity for diverse differentiation. Recently, certain histologic variants of UC have been recognized to be associated with unfavorable clinical outcomes. Several UC studies have also suggested that tumor budding is a poor prognostic marker. Distant metastasis of UC after radical cystectomy is not uncommon. However, these metastatic lesions are not routinely confirmed with histology.

Methods

We investigated the histopathologic features of 13 cases of UC with biopsy-proven distant metastases, with a special emphasis on histologic variants and tumor budding.

Results

Lymph nodes (6/13, 46%) were the most common metastatic sites, followed by the lung (4/13, 31%), liver (4/13, 31%), and the adrenal gland (2/13, 15%). The histologic variants including squamous (n = 1), micropapillary (n = 4), and plasmacytoid (n = 1) variants in five cases of UC. Most histologic variants (4/5, 80%) of primary UCs appeared in the metastatic lesions. In contrast, high-grade tumor budding was detected in six cases (46%), including one case of non-muscle invasive UC. Our study demonstrates that histologic variants are not uncommonly detected in distant metastatic UCs. Most histologic variants seen in primary UCs persist in the distant metastatic lesions. In addition, high-grade tumor budding, which occurs frequently in primary tumors, may contribute to the development of distant metastasis.

Conclusions

Therefore, assessing the presence or absence of histologic variants and tumor budding in UCs of the urinary bladder, even in non-muscle invasive UCs, may be useful to predict distant metastasis.

Immunohistochemical over-expression of HER2 does not always match with gene amplification in invasive bladder cancer

BACKGROUND

HER2 is a potential target of therapy in urothelial cancer (UC). Pathological case stratification according to HER2 gene amplification or HER2 protein overexpression was critical for patients' selection in previous unsuccessful clinical trial with HER2 targeting agents.

STUDY DESIGN

We evaluated the HER2 overexpression by immunohistochemistry (IHC) together with the amplification of the HER2 gene with chromogenic(CISH) and fluorescent (FISH) in situ hybridization in a cohort of 61 patients covering the whole spectrum of bladder UC variants, using a tissue microarray (TMA) approach.

RESULTS

IHC was available in all the 61 cases while ISH in 37 and FISH in 42. At IHC, 2/61 cases (3%) were scored 3+; 2 (3%) scored 2+; 2 (3%) scored 1+; the remaining 55 (91%) scored 0. At CISH analysis 10/37 cases (27%) were amplified, 6 cases with HER2 amplification showed positive HER2 IHC (3+, 2+, 1+). Seven cases with IHC score 0 were amplified at CISH. FISH analysis revealed an amplification in 5/42 cases (12%). The total number of HER2amplified cases was different between chromogenic and fluorescent ISH with 5 cases amplified using FISH compared to 10 with CISH.

CONCLUSIONS

In clinical trials with HER2 targeting agents the candidate patients should be investigated not only by IHC but also by ISH, independently of the IHC results. Since also usual type UC can overexpress HER2 we recommend to extend the patients' selection to all the histotypes of bladder cancer other than the micropapillary type.

Bladder Stones Associated with an Aggressive Plasmacytoid Variant of Urothelial Cancer: A Rare Case and Literature Review

Urothelial carcinoma is the most common histologic subtype of bladder cancer, accounting for approximately 90%. We herein report a case of a 78-year-old man with an unusual association of bladder stones with an aggressive plasmacytoid variant of urothelial cancer. Initially he presented in 2009 with a very large bladder stone and was treated by an open cystolithotomy. Histology from a bladder biopsy at that time was benign. He failed to attend follow-up appointments but subsequently he attended in 2016 with a recurrent urinary tract infection and an acute kidney injury. A CT scan showed multiple bladder stones. The cause of our patients' multiple bladder stones is unclear and unusual. He then underwent a further open cystolithotomy according to our multidisciplinary team recommendation. Post-operatively he unfortunately developed a non-healing vesicocutaneous fistula for which he was performed cystoscopy and biopsy but ended with transurethral resection due to the extent of abnormal/necrotic tissue. Histology confirmed a plasmacytoid variant of urothelial cancer. To our knowledge, this is the first case of an association of bladder stones with a plasmacytoid variant of urothelial cancer.

The Impact of Plasmacytoid Variant Histology on the Survival of Patients with Urothelial Carcinoma of Bladder after Radical Cystectomy

BACKGROUND

The clinical significance of the plasmacytoid variant (PCV) in urothelial carcinoma (UC) is currently lacking.

OBJECTIVE

To compare clinical outcomes of patients with any PCV with that of patients with pure UC treated with radical cystectomy (RC).

DESIGN, SETTING, AND PARTICIPANTS

We identified 98 patients who had pathologically confirmed PCV UC and 1312 patients with pure UC and no variant history who underwent RC at our institution between 1995 and 2014.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Univariable and multivariable Cox regression and Cox proportional hazards regression to determine if PCV was associated with overall survival (OS).

RESULTS AND LIMITATIONS

Patients with PCV UC were more likely to have advanced tumor stage (p=0.001), positive lymph nodes (p=0.038), and receive neoadjuvant chemotherapy than those with pure UC (46% vs 22%, p<0.0001). The rate of positive soft tissue surgical margins was over five times greater in the PCV UC group compared with the pure UC group (21% vs 4.1%, respectively, p<0.0001). Median OS for the pure UC versus the PCV patients were 8 yr and 3.8 yr, respectively. On univariable analysis, PCV was associated with an increased risk of overall mortality (hazard ratio=1.34, 95% confidence interval: 1.02-1.78, p=0.039). However, on multivariable analysis adjusted for age, sex, neoadjuvant chemotherapy received, lymph node status, pathologic stage, and soft margin status, the association between PCV and OS was no longer significant (hazard ratio=1.06, 95% confidence interval: 0.78, 1.43, p=0.7). This retrospective study is limited by the lack of pathological reanalysis, and the impact of other concurrent mixed histology cannot be determined in this study.

CONCLUSIONS

Patients with PCV features have a higher disease burden at RC compared with those with pure UC. However, PCV was not an independent predictor of survival after RC on multivariable analysis, suggesting that PCV histology should not be used as an independent prognostic factor.

PATIENT SUMMARY

Plasmacytoid urothelial carcinoma is a rare and aggressive form of bladder cancer. Patients with plasmacytoid urothelial carcinoma had worse adverse pathologic features, but this was not associated with worse overall mortality when compared with patients with pure urothelial carcinoma.

Variant morphology in upper urinary tract urothelial carcinoma: a 14-year case series of biopsy and resection specimens

Upper urinary tract urothelial carcinoma exhibiting variant morphology, especially in higher-grade tumors, is a recognized phenomenon but has not been comparatively studied in biopsy versus resection material. We studied the morphologic patterns and clinicopathological features, and provide a comparison between biopsy and resection specimens. Consultation cases were evaluated separately to investigate for possible consultation bias. A total of 383 in-house cases from 352 patients including 314 resection specimens and 69 biopsies from 2001 to 2014 were reviewed from a single institution. Histologic type, tumor grade, invasion, pathologic stage, nodal status, metastasis, and the presence and type of variant morphology for each case were evaluated. Variant morphology was identified in 5 biopsy specimens (7.2%) and 42 resection specimens (13.4%). The most common variant morphologic pattern was squamous differentiation (16 cases, 4.5%) followed by an inverted growth pattern (8 cases, 2.2%). The presence of variant morphology in resection specimens had a significant association with higher tumor grade, higher pT stage, and nonpapillary configuration. Of 69 patients with biopsies, 31 had a subsequent resection. In comparison, 181 consultation cases from 168 patients showed variant morphology in 6 biopsies (7.1%) and 27 resections (28.1%). In conclusion, the frequency of recognizing variant morphology in biopsies is about one-half of that in resections. The inclusion of consultation cases can inflate the incidence of variant morphology. As a result, the frequency of variant morphology in our in-house cases is lower than the percentage reported in the literature, most likely secondary to a consultation bias.

S100P as a Marker for Urothelial Histogenesis: A Critical Review and Comparison With Novel and Traditional Urothelial Immunohistochemical Markers

S100P, or placental S100, is a member of a large family of S100 proteins and considered to be a promising immunohistochemical marker to support urothelial differentiation. This review synthesizes published data regarding the expression of S100P in urothelial carcinoma across histological grade and variant patterns, and in other malignancies, in an effort to summarize the state of understanding of this marker and evaluate its potential. We provide also a broad comparison of S100P with other contemporary and traditional urothelial markers and outline the potential utility of S100P in various diagnostically challenging scenarios. Taken in context, we recommend that to provide immunohistochemical support for consideration of urothelial differentiation, S100P may be included in a panel of markers (due to its high sensitivity), with better established (GATA3) and more specific (uroplakin 2) markers, for comparison with corresponding markers of other primary sites under consideration, depending on the clinical context. We emphasize that the overall most appropriate panel for any given case depends on the differential diagnosis engendered by the morphology encountered, and the constellation of clinical findings. As always with immunohistochemical panels, expected positive and negative markers for each diagnostic consideration should be included. Finally, since as of date there are no optimally sensitive or specific markers of urothelial differentiation, all final diagnoses relying on immunohistochemical support should be made in the appropriate clinical and histological context.

Sarcomatoid Urothelial Carcinoma of the Bladder: Analysis of 28 Cases With Emphasis on Clinicopathologic Features and Markers of Epithelial-to-Mesenchymal Transition

Context.—Sarcomatoid urothelial carcinoma (UCa) is a rare but aggressive variant of bladder cancer that can show diagnostic challenges even using ancillary techniques.

Objective.—To examine immunohistochemical markers in the context of sarcomatoid UCa, including those associated with epithelial-to-mesenchymal transition.

Design.—Twenty-eight cases of sarcomatoid UCa were rereviewed. Clinical outcomes were obtained through database search. Immunohistochemistry for clinical and epithelial-to-mesenchymal transition markers was performed.

Results.—All patients had biopsy-proven invasive UCa; 61% (17 of 28) had sarcomatoid UCa at initial diagnosis. A recognizable epithelial component(s) was present in 17 lesions. The sarcomatoid component accounted for 65% of the lesion (average), with heterologous elements present in 3 of 28 cases (11%). The morphologic spectrum of the sarcomatoid element included spindled not otherwise specified, myxoid, pseudoangiosarcomatous, and malignant fibrous histiocytoma–like undifferentiated features. The sarcomatoid component was immunoreactive for pancytokeratin (22 of 26; 85%), p63 (20 of 26; 77%), cytokeratin 903 (17 of 26; 65%), cytokeratin 7 (16 of 26; 62%), GATA3 (16 of 26; 62%), and cytokeratin 5/6 (16 of 26; 62%). STAT-6, CD31, CD34, and HMB45 were all nonreactive, whereas smooth muscle actin often showed at least focal immunoreactivity (22 of 26; 85%). Epithelial-to-mesenchymal transition markers were frequently expressed, including vimentin (26 of 26; 100%), FoxC2 (26 of 26; 100%), SNAIL (23 of 26; 88.5%), and ZEB1 (18 of 26; 69.2%). Follow-up was available for 24 patients (median, 7 months). Sixteen of 28 patients (57%) died of disease (overall mean survival, 9.1 months). The presence of myxoid or chordoid features was associated with reduced survival (P &lt; .05).

Conclusions.—Sarcomatoid UCa is an aggressive form of UCa that frequently expresses epithelial-to-mesenchymal transition markers, suggesting a possible mechanism associated with aggressive tumor behavior.

Gene Expression Profile of the Clinically Aggressive Micropapillary Variant of Bladder Cancer

BACKGROUND

Progression of conventional urothelial carcinoma of the bladder to a tumor with unique microscopic features referred to as micropapillary carcinoma is coupled with aggressive clinical behavior signified by a high propensity for metastasis to regional lymph nodes and distant organs resulting in shorter survival.

OBJECTIVE

To analyze the expression profile of micropapillary cancer and define its molecular features relevant to clinical behavior.

DESIGN, SETTING, AND PARTICIPANTS

We retrospectively identified 43 patients with micropapillary bladder cancers and a reference set of 89 patients with conventional urothelial carcinomas and performed whole-genome expression messenger RNA profiling.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The tumors were segregated into distinct groups according to hierarchical clustering analyses. They were also classified according to luminal, p53-like, and basal categories using a previously described algorithm. We applied Ingenuity Pathway Analysis software (Qiagen, Redwood City, CA, USA) and gene set enrichment analysis for pathway analyses. Cox proportional hazards models and Kaplan-Meier methods were used to assess the relationship between survival and molecular subtypes. The expression profile of micropapillary cancer was validated for selected markers by immunohistochemistry on parallel tissue microarrays.

RESULTS AND LIMITATIONS

We show that the striking features of micropapillary cancer are downregulation of miR-296 and activation of chromatin-remodeling complex RUVBL1. In contrast to conventional urothelial carcinomas that based on their expression can be equally divided into luminal and basal subtypes, micropapillary cancer is almost exclusively luminal, displaying enrichment of active peroxisome proliferator-activated receptor γ and suppression of p63 target genes. As with conventional luminal urothelial carcinomas, a subset of micropapillary cancers exhibit activation of wild-type p53 downstream genes and represent the most aggressive molecular subtype of the disease with the shortest survival. The involvement of miR-296 and RUVBL1 in the development of micropapillary bladder cancer was identified by the analyses of correlative associations of genome expression profiles and requires mechanistic validation.

CONCLUSIONS

Micropapillary cancer evolves through the luminal pathway and is characterized by the activation of miR-296 and RUVBL1 target genes.

PATIENT SUMMARY

Our observations have important implications for prognosis and for possible future development of more effective therapies for micropapillary bladder cancer.

Bladder preserving approach for liposarcomatoid variant of transitional urothelial carcinoma

Urothelial carcinoma of the bladder with variant histologies is usually underdiagnosed and understaged. It is found in <25% of cases during transurethral resection of bladder tumours. The majority of cases carry a worse prognosis, with higher rates of recurrence and progression, and should be managed aggressively. Here, we report a rare case of liposarcomatoid variant of urothelial carcinoma managed by partial cystectomy and standard pelvic lymph node dissection.

Usefulness of pT1 substaging in papillary urothelial bladder carcinoma

Background

When treating bladder cancer patients, the most significant problems usually concern cases with high-grade non-muscle-invasive carcinoma, and a better understanding of which patients would benefit from early radical cystectomy is urgently needed. The uropathology community is seeking more user-friendly approaches to distinguishing between T1 cancers exhibiting different types of clinical behavior.

Methods

After a retrospective review, we selected a group of 314 patients who underwent transurethral resection of the bladder (TURB) and were diagnosed with high-grade urothelial carcinoma staged as T1. Three different substaging systems were applied: one was the anatomy-based T1 a/b; and two involved micrometric thresholds of either 0.5 mm of invasion (as proposed by van Rhijn et al.), or 1 mm of invasion (as proposed in the present study). Early reTUR (repeated transurethral resection) was performed in 250 patients, and the same substaging approaches were applied to cases of T1.

Results

It proved feasible to apply the 1 mm substaging system in 100 % of cases, the van Rhijn system in 100 %, and the anatomy-based method (T1 a/b) in 72.3 % of cases. At a mean follow-up of 46 months, the recurrence-free survival rate was significantly better (p < 0.001) in the group that underwent reTUR, while none of the three substaging systems reliably predicted recurrences. The 1 mm did seem promising, however, as a threshold for predicting progression, reaching statistical significance in the Kaplan Meier estimates (p < 0.04).

Conclusion

Our study shows that micrometric substaging is feasible in this setting and should be extended to include any early reTUR to complete the substaging done after the first TURB. It can also provide helpful prognostic information.

Plasmacytoid variant of urothelial carcinoma: Diagnostic challenges and role of immunohistochemistry

Plasmacytoid carcinoma of the urinary bladder or plasmacytoid urothelial carcinoma (PUC) is rare and only recently described a histological variant of transitional cell carcinoma. The morphological resemblance of PUC to other malignancies is a source of diagnostic dilemmas and often misdiagnosis. Immunohistochemistry plays a pivotal role in narrowing the differential diagnosis and reaching to a conclusive diagnosis. A diagnosis of PUC usually carries a dismal prognosis. Hence, correct diagnosis is important. We report here a 52-year-old male with a plasmacytoid variant of urothelial carcinoma.

Pleomorphic giant cell carcinoma of the urinary bladder: an extreme form of tumour de-differentiation

AIMS

Vesical pleomorphic giant cell carcinoma (PGCC) is a variant of urothelial carcinoma (UC) characterized by highly pleomorphic tumour with giant cells. Fewer than 10 cases have been reported, and our aim was to determine the clinical and pathological features of a series of tumours from a specialized uropathology laboratory.

METHODS AND RESULTS

Thirteen cases of PGCC of the bladder were identified. There were nine males and four females, ranging in age from 53 to 92 years (mean 72 years). Associated conventional high-grade UC was seen in eight cases, while three cases also had micropapillary UC and one plasmacytoid UC. UC in situ (CIS) was present in five cases and occasional bizarre cells were seen in both UC and CIS. The proportion of PGCC present varied from 40% to 100% of tumour. Immunostaining performed on 10 cases showed uniform positivity for CK 8/18 and AE1/AE3, while most tumours were positive for CK7, CK20, uroplakin III and GATA binding protein 3 (GATA3). β-human chorionic gonadotrophin (β-hCG) was negative. Of 10 patients with follow-up, five died within 1 year and four are alive with tumour.

CONCLUSIONS

The association of PGCC with UC and an overlap in immunoexpression suggests that PGCC represents an extreme form of UC de-differentiation.

Update for the practicing pathologist: The International Consultation On Urologic Disease-European association of urology consultation on bladder cancer

The International Consultations on Urological Diseases are international consensus meetings, supported by the World Health Organization and the Union Internationale Contre le Cancer, which have occurred since 1981. Each consultation has the goal of convening experts to review data and provide evidence-based recommendations to improve practice. In 2012, the selected subject was bladder cancer, a disease which remains a major public health problem with little improvement in many years. The proceedings of the 2nd International Consultation on Bladder Cancer, which included a 'Pathology of Bladder Cancer Work Group,' have recently been published; herein, we provide a summary of developments and consensus relevant to the practicing pathologist. Although the published proceedings have tackled a comprehensive set of issues regarding the pathology of bladder cancer, this update summarizes the recommendations regarding selected issues for the practicing pathologist. These include guidelines for classification and grading of urothelial neoplasia, with particular emphasis on the approach to inverted lesions, the handling of incipient papillary lesions frequently seen during surveillance of bladder cancer patients, descriptions of newer variants, and terminology for urine cytology reporting.

Whorled Urothelial Cell Carcinoma: A Neglected Variant

Twelve cases of urothelial cell papillary carcinoma with a whorled pattern of growth are described. This variant is reported with clinicopathological correlations and immunohistochemical findings. All cases showed this peculiar and distinctive curlicue histological pattern, ranging from 50% to 100% of the neoplastic population. Despite the disordered/turbulent growth pattern, the cytological grade was uniformly low. All the lesions were Ta staged and no patient experienced progression after transurethral resection, while 2 showed clinical recurrences. The immunophenotype (low p53, high p27, low Ki67, and high GATA3) of the cases contributes to define this rare variant as a low-grade tumor.

Late-onset distant metastatic upper urinary tract urothelial carcinoma mimicking lung adenocarcinoma

Urothelial carcinomas (UCs) can occur in the upper urinary tract or lower urinary tract. Upper urinary tract urothelial carcinoma (UUT-UC) is relatively a rare disease and accounts for only about 5% of UC cases. Sporadic cases of late-onset metastasis, associated with UC of the bladder, have occasionally been reported. In contrast, no late-onset distant metastatic UUT-UC without local recurrence has, to the best of our knowledge, been reported in the English literature. We report an extremely rare case of distant metastatic UC, mimicking lung adenocarcinoma that originated from UUT-UC 12 years previously.

Case report and review of the literature: Rectal linitis plastica secondary to the lipoid cell variant of transitional cell carcinoma of the urinary bladder

The overall 5-year survival of patients with urothelial carcinoma of the bladder (UC) is about 78%; however, there are some rare subtypes. One of these is the lipoid cell subtype, which bears a very poor prognosis. Another rare disease entity with a poor prognosis is metastasis to the lower gastrointestinal tract in the form of secondary linitis plastica of the rectum. We describe an extremely rare and unique case of rectal linitis plastica secondary to the rare lipoid cell variant of UC.

FTIR microspectroscopy of selected rare diverse sub-variants of carcinoma of the urinary bladder

Urothelial carcinomas of the bladder are a heterogeneous group of tumours, although some histological sub-variants are rare and sparsely reported in the literature. Diagnosis of sub-variants from conventional urothelial carcinoma can be challenging, as they may mimic the morphology of other malignancies or benign tumours and therefore their distinction is important. For the first time, the spectral pathology of some of these sub-variants has been documented by infrared microspectroscopy and an attempt made to profile their biochemistry. It is important not only to identify and separate the cancer-associated epithelial tissue spectra from common tissue features such as stroma or blood, but also to detect the signatures of tumour sub-variants. As shown, their spectroscopic signals can change dramatically as a consequence of differentiation. Example cases are discussed and compared with histological evaluations.

Molecular basis of urinary bladder cancer

Bladder cancer is a relatively common and potentially life-threatening neoplasm. The diagnosis of urothelial carcinoma usually entails a lifelong surveillance to detect recurrent disease. In recent years, significant progress has been made in understanding the molecular mechanisms of carcinogenesis in urinary bladder. An early step in the process of carcinoma development is establishment of a premalignant abnormal urothelial patch that may give rise to various types of urothelial carcinoma and may provide a fertile ground for development of multifocal synchronous and metachronous tumors. Two distinct molecular pathways are involved. Low-grade papillary carcinoma is associated with mutation in the FGFR3 or in some cases mutations in RAS genes. High-grade in situ/muscle-invasive carcinoma on the other hand is characterized by alteration of p53 and pRB. Loss of function of these key genes, which play a crucial role in the control of cell cycle, leads to accumulation of additional mutations and deletions of genes resulting in an aggressive phenotype. It is hoped that a thorough understanding of the molecular basis of urothelial cancer will facilitate early diagnosis and will lead to development of new modalities for the management and treatment of these carcinomas.

ROS generation via NOX4 and its utility in the cytological diagnosis of urothelial carcinoma of the urinary bladder

Background

Reactive oxygen species (ROS) production via NADPH oxidase (NOX) contributes to various types of cancer progression. In the present research, we examined the pathobiological role of NADPH oxidase (NOX)4-mediated generation of reactive oxygen species (ROS) in urothelial carcinoma (UC) of the urinary bladder, and demonstrated the utility of ROS labeling in urine cytology.

Methods

NOX4 gene was silenced in vivo and in vitro by NOX4 siRNA transfection with or without atlocollagen. Cell cycle and measurement of ROS were analyzed by flowcytometry. Orthotopic implantation animal model was used in vivo experiment. NOX4 expression in urothelial carcinoma cells was observed by immunohistochemical analysis using surgical specimens of human bladder cancer. Urine cytology was performed after treatment with ROS detection reagents in addition to Papanicolaou staining.

Results

NOX4 was overexpressed in several UC cell lines and the NOX inhibitor, diphenylene iodonium reduced intracellular ROS and induced p16-dependent cell cycle arrest at the G1 phase. Moreover, silencing of NOX4 by siRNA significantly reduced cancer cell growth in vivo as assessed in an orthotopic mouse model. Immunohistochemistry demonstrated high expression of NOX4 in low grade/non-invasive and high grade/invasive UC including precancerous lesions such as dysplasia but not in normal urothelium. Then, we assessed the usefulness of cytological analysis of ROS producing cells in urine (ROS-C). Urine samples obtained from UC cases and normal controls were treated with fluorescent reagents labeling the hydrogen peroxide/superoxide anion and cytological atypia of ROS positive cells were analyzed. As a result, the sensitivity for detection of low grade, non-invasive UC was greatly increased (35% in conventional cytology (C-C) vs. 75% in ROS-C), and the specificity was 95%. Through ROS-C, we observed robust improvement in the accuracy of follow-up urine cytology for cases with previously diagnosed UC, especially in those with low grade/non-invasive cancer recurrence (0% in C-C vs. 64% in ROS-C).

Conclusions

This is the first report demonstrating that ROS generation through NOX4 contributes to an early step of urothelial carcinogenesis and cancer cell survival. In addition, cytology using ROS labeling could be a useful diagnostic tool in human bladder cancer.

Fine needle aspiration cytology of a case of micropapillary variant of urothelial carcinoma of bladder

Neoplastic urothelium has the capacity to demonstrate enormous plasticity. A variety of unusual morphological variants of urothelial carcinoma have been described. Micropapillary variant of urothelial carcinoma is a rare and recently described bladder tumor, associated with poor prognosis. We present the cytological features of micropapillary urothelial carcinoma in a 65-year-old man with bladder mass. The cytological features include tightly cohesive clusters of micropapillary component admixed with urothelial carcinoma. Histopathological sections showed small nests of tumor cells residing within the lacunae. Establishing a diagnosis of micropapillary urothelial carcinoma indicates a high-grade and high-stage tumor with poor outcome, requiring an aggressive therapy. It is thus important for the cytopathologist to recognise micropapillary variant of urothelial carcinoma, for early and better management of patients with bladder tumor.

Nest-Like Features in Bladder, Simulating the Nested Variant of Urothelial Carcinoma

Nest-like structures are the cardinal lesion of different benign and malignant bladder entities. These entities emphasize the biological relevance of the subtle morphological nest plasticity. The authors present 25 benign and malignant neoplasms, sharing the presence of florid nest-like growth and the scarcity or absence of superficial papillary components. Differential diagnostic clues are discussed.

Histological variants of urothelial carcinoma: diagnostic, therapeutic and prognostic implications

It is well established that invasive urothelial carcinoma, involving the urinary bladder and renal pelvis, has marked propensity for divergent differentiation. In recent years, several 'variant' morphologies have been described and most have been recognized in the 2004 World Health Organization Classification. These histological variants of urothelial carcinoma have clinical significance at various levels, including diagnostic, that is, awareness of the morphological variant is essential in order to avoid diagnostic misinterpretations; prognostic for patient risk stratification; and therapeutic, where a diagnostic assignment of a particular variant may be associated with the administration of a therapy distinctive from that used in conventional invasive urothelial carcinoma. The diagnoses of micropapillary urothelial carcinoma, small-cell carcinoma, lymphoepithelioma-like carcinoma and sarcomatoid carcinoma are prime examples where treatment protocols may be different than the usual muscle-invasive bladder cancer. This review discusses the variants of urothelial carcinoma, outlining for each the diagnostic features, differential diagnostic considerations and the clinical significance.

Plasmacytoid urothelial carcinoma of the bladder: a case report

Plasmacytoid bladder cancer is a rare variant of transitional cell carcinoma. A 57-year-old man was referred to our institution for management of invasive transitional cell carcinoma diagnosed at a peripheral hospital. His complaints were of vague lower abdominal pain with associated urgency and frequency requiring oxybutynin. Metastatic workup was negative and was subsequently scheduled for a radical cystectomy. Routine colonoscopy 3 weeks prior to surgery was negative. Intraoperatively, he was found to have metastatic urothelial cancer involving the cecum and multiple metastatic deposits within the mesentery of the small intestines. He underwent a palliative cystectomy with ileal conduit formation. Final pathology revealed metastatic plasmacytoid variant of urothelial cancer. Histology and immunohistochemistry were compatible with plasmacytoid variant of urothelial cancer. Here we present our case of this rare variant of urothelial cancer with a review of its characteristics.

Plasmacytoid urothelial carcinoma of the bladder: a case report

Plasmacytoid bladder cancer is a rare variant of transitional cell carcinoma. A 57-year-old man was referred to our institution for management of invasive transitional cell carcinoma diagnosed at a peripheral hospital. His complaints were of vague lower abdominal pain with associated urgency and frequency requiring oxybutynin. Metastatic workup was negative and was subsequently scheduled for a radical cystectomy. Routine colonoscopy 3 weeks prior to surgery was negative. Intraoperatively, he was found to have metastatic urothelial cancer involving the cecum and multiple metastatic deposits within the mesentery of the small intestines. He underwent a palliative cystectomy with ileal conduit formation. Final pathology revealed metastatic plasmacytoid variant of urothelial cancer. Histology and immunohistochemistry were compatible with plasmacytoid variant of urothelial cancer. Here we present our case of this rare variant of urothelial cancer with a review of its characteristics.

Utility of diagnostic and prognostic markers in urothelial carcinoma of the bladder

Urothelial carcinoma (UCC) of the bladder demonstrates diverse morphologic features, often leading to diagnostic challenges in the discrimination between UCC and benign mimickers of neoplasia, and between primary UCC and secondary neoplasms involving the bladder. In situ lesions also provide diagnostic difficulty in some instances, most prominently in the distinction between normal, reactive urothelium and flat urothelial carcinoma in situ. The use of ancillary techniques, including panels of immunohistochemical markers, in distinguishing these entities has aided not only in the diagnosis of UCC, but has also provided insight into the molecular pathogenesis and prognostic value of numerous molecular pathways in UCC. This review focuses on some of the more commonly encountered biomarkers in UCC and their role in addressing key diagnostic and prognostic issues in this disease process.