Invasive micropapillary urothelial carcinoma of the bladder

Characterizing the Genomic Landscape of the Micropapillary Subtype of Urothelial Carcinoma of the Bladder Harboring Activating Extracellular Mutations of ERBB2

The micropapillary subtype of urothelial carcinoma (MPUC) of the bladder is a very aggressive histological variant of urothelial bladder cancer (UBC). A high frequency of MPUC contains activating mutations in the extracellular domain (ECD) of ERBB2. We sought to further characterize ERBB2 ECD-mutated MPUC to identify additional genomic alterations that have been associated with tumor progression and therapeutic response. In total, 5,485 cases of archived formalin-fixed, paraffin-embedded UBC underwent comprehensive genomic profiling to identify ERBB2 ECD-mutated MPUC and evaluate the frequencies of genomic co-alterations. We identified 219 cases of UBC with ERBB2 ECD mutations (74% S310F and 26% S310Y), of which 63 (28.8%) were MPUC. Genomic analysis revealed that TERT, TP53, and ARID1A were the most common co-altered genes in ERBB2-mutant MPUC (82.5%, 58.7%, and 39.7%, respectively) and did not differ from ERBB2-mutant non-MPUC (86.5%, 51.9%, and 35.3%). The main differences between ERBB2 ECD-mutated MPUC compared with non-MPUC were KMT2D, RB1, and MTAP alterations. KMT2D and RB1 are tumor-suppressor genes. KMT2D frequency was significantly decreased in ERBB2 ECD-mutated MPUC (6.3%) in contrast to non-MPUC (27.6%; P < .001). RB1 mutations were more frequent in ERBB2 ECD-mutated MPUC (33.3%) than in non-MPUC (17.3%; P = .012). Finally, MTAP loss, an emerging biomarker for new synthetic lethality-based anticancer drugs, was less frequent in ERBB2 ECD-mutated MPUC (11.1%) than in non-MPUC (26.9%; P = .018). Characterizing the genomic landscape of MPUC may not only improve our fundamental knowledge about this aggressive morphological variant of UBC but also has the potential to identify possible prognostic and predictive biomarkers that may drive tumor progression and dictate treatment response to therapeutic approaches.

Invasive Micropapillary Urothelial Carcinoma: an Uncommon and Underreported Variant in Cystectomy Specimens

Conventional urothelial carcinoma is the most common histological type of urinary bladder carcinoma. The latest edition of the WHO classification of tumours of the urothelial tract lays special emphasis on the ability of urothelial tumours to exhibit divergent differentiation with multiple histologic variants and a diverse genomic landscape. The presence of a micropapillary component (MPC) in urothelial carcinoma is associated with high-grade disease and poor response to intravesical chemotherapy. The present study aims to enumerate the clinicohistological features of urothelial carcinomas with micropapillary differentiation. Slides from 144 radical cystectomy specimens received over 6 years were reviewed independently by two pathologists. A predominant histological pattern along with co-existing pathology was noted. Of these, five cases were pure micropapillary carcinomas, four had conventional urothelial carcinoma with a MPC, one had a microscopic tumour at the mucosal surface, and two cases showed micropapillary histology in the lymph node metastasis, following transurethral resection of bladder tumour and Bacillus Calmette-Guerin therapy. The tumours with pure micropapillary carcinoma presented with a higher pathological stage and poor overall survival. Organ and lymph node metastasis was noted in five and eight cases, respectively, of which six showed a micropapillary pattern in the lymph nodes. Micropapillary urothelial carcinoma is a rare and aggressive variant of urothelial carcinoma with unique histologic features. This variant is often missed and underreported in biopsy and surgical resection specimens. Since the presence of MPC confers a poorer prognosis, the identification and reporting of this entity are important.

T1 bladder carcinoma with variant histology: pathological features and clinical significance

The aim of the study was to stratify high-grade T1 (HGT1) bladder urothelial carcinoma into risk categories based on the presence of variant histology when compared to conventional urothelial carcinoma. The clinicopathological features of 104 HGT1 cases of urothelial carcinoma of the bladder with variant histology present in 34 (37%) were assessed. The endpoint of the study was disease-free survival and cancer-specific survival. Overall, variant histology was identified as a significant predictor of disease-free survival (P = 0.035). The presence of any specific variant histology (squamous, glandular, micropapillary, nested, microcystic, inverted growth, villous-like, basaloid, and lymphoepithelioma-like) was identified as a significant predictor of disease-free survival (P = 0.008) and cancer-specific survival (P = 0.0001) in HGT1 bladder cancer. Therefore, our results support including micropapillary HGT1 urothelial carcinoma within the aggressive high-risk category, as suggested by some recent clinical guidelines, but also favor nested, glandular, and basaloid to be placed in the high-risk category due to their potential of aggressive, life-threatening behavior and their limited response to bacillus Calmette-Guerin therapy. Conversely, the low-risk category would include urothelial carcinomas with squamous, inverted growth, or microcystic morphology, all with limited life-threatening potential and good response to current therapy. A very low-risk category would finally include patients whose tumors present villous-like or lymphoepithelioma-like morphology. In conclusion, our findings support the value of reporting the variant histology as a feature of variable aggressiveness in HGT1 urothelial carcinoma of the bladder.

Bladder Cancer Sample Handling and Reporting: Pathologist's Point of View

The aim of this narrative review is to provide adequate information on handling and reporting of the bladder cancer samples to improve the closely collaboration between pathologists and urologists. The main (but not exclusive) research tool used was PubMed and 87 references were selected and quoted in the text. We have considered handling of biopsies, transurethral resection (TUR), and cystectomy specimens to summarize the different methods of sampling and the related issues. Moreover, we considered and discussed the main prognostic factors, such as histological tumor type, grade, and stage of bladder cancer, that should be described in the pathological report. In addition, critical issues encountered in the interpretation of histological samples were discussed.

Molecular pathology of urothelial carcinoma

The current personalized oncology era has witnessed significant efforts to integrate clinical, pathological, and molecular classifications. The growing need for molecular biomarkers to feed personalized oncology, together with the unprecedented wealth of knowledge on the molecular basis of bladder cancer, has led to a novel approach to this disease, incorporating molecularly generated data in clinical practice for locally advanced or metastatic disease. Translational research allows a better understanding of the early events in the development of urothelial carcinoma in the urinary bladder. Thus, mutations in the KMT2D and KDM6A chromatin-modifying genes confer competitive advantages that drive cells to colonize larger regions of the urothelium. Additional mutations in TP53, PIK3CA, FGFR3, or RB1 genes then trigger the process of malignant transformation in the urothelium. In the current review, we provide an overview of what could be the expected transition from the morphology-based classification to a combined, molecularly enriched reporting of clinically meaningful parameters aiming to promote personalized oncology of urothelial carcinoma.

Non-Muscle Invasive Bladder Cancer with Variant Histology: Biological Features and Clinical Implications

BACKGROUND

The most common bladder cancer (BC) histotype is pure urothelial carcinoma (UC), which may undergo divergent differentiation in some cases. Variant histology (VH) presents along variable morphologies, either single or combined between them or with pure UC. From a clinical standpoint, the vast majority of BC is diagnosed at non-invasive or minimally invasive stages, namely as non-muscle invasive BC (NMIBC). There is a wide range of therapeutic options for patients with NMIBC, according to their clinical and pathological features. However, current risk stratification models do not show optimal effectiveness. Evidence from the literature suggests that VH has peculiar biological features, and may be associated with poorer survival outcomes compared to pure UC.

SUMMARY

In order to describe the biological features and prognostic/predictive role of VH in NMIBC, and to discuss current treatment options, we performed a systematic literature search through multiple databases (PubMed/Medline, Google Scholar) for relevant articles according to the following terms, single and/or in combination: "non-muscle invasive bladder cancer," "variant histology," "micropapillary variant," "glandular differentiation," "squamous differentiation," "nested variant," "plasmacytoid variant," and "sarcomatoid variant." We extracted 99 studies including original articles, reviews, and systematic reviews, and subsequently analyzed data from 16 studies reporting on the outcome of NMIBC with VH. We found that the relative rarity of these forms as well as the heterogeneity in study populations and therapeutic protocols results in conflicting findings overall. Key Messages: The presence of VH should be taken into account when counseling a patient with NMIBC, since it may upgrade the disease to high-risk tumor and thus warrant a more aggressive treatment.

Cervical carcinomas with serous-like papillary and micropapillary components: illustrating the heterogeneity of primary cervical carcinomas

Recent changes in the classification of cervical adenocarcinomas have re-categorized serous carcinoma as potentially nonexistent. However, clinical and pathological profiles of cervical adenocarcinomas with serous-like morphological features have not been systematically evaluated using the latest taxonomy and biomarkers. We studied 14 cases of primary cervical carcinomas with serous-like morphologies (papillary and micropapillary patterns). None of these cases exhibited evidence of serous carcinoma involving the upper tracts. Patient ages ranged between 34 and 86 years, most presented with abnormal uterine bleeding. Histologically, ten cases were classified as human papillomavirus (HPV)-associated carcinomas (eight usual-type endocervical adenocarcinomas and two adenosquamous carcinomas), of which six exhibited a papillary pattern and four had a micropapillary pattern. The four remaining cases were HPV-independent gastric-type adenocarcinomas, which displayed a papillary pattern in one case and a micropapillary pattern in three others. All ten HPV-associated carcinomas displayed block positive p16 and wild-type p53 by immunohistochemistry, with nine of them confirmed by HPV testing. Two of the four gastric-type adenocarcinomas had mutation-type p53, one of which also being p16 block positive. HER2 overexpression was demonstrated in 3/14 (21.4%) cases (2 HPV-associated and 1 HPV-independent). PD-L1 expression was identified in 4/10 (40%) cases, all HPV-associated. Targeted next-generation sequencing was performed in two cases with a micropapillary pattern, revealing a missense variant in ATM in an HPV-associated tumor and missense variants in TP53 and SMARCB1 in an HPV-independent tumor. The results demonstrated that primary endocervical adenocarcinomas can mimic the appearance of serous carcinoma, while not representing serous carcinoma. Serous-like papillary and micropapillary patterns may be present in both HPV-associated and HPV-independent cervical carcinomas, but none of the cases studied were unequivocally serous upon detailed analysis. Our findings support the exclusion of "cervical serous carcinoma" from existing classifications of cervical adenocarcinoma.

Stage T1 bladder cancer: diagnostic criteria and pitfalls

Accurate pathological staging is crucial for patient management. Patients with T1 bladder cancer are at risk of recurrence, progression, and death of cancer. Recognition of early invasion (stage T1 disease) in urothelial carcinoma remains one of the most challenging areas in urological surgical pathology practice. A logical roadmap to T1 diagnosis would include careful evaluation of histological grade, stromal epithelial interface, characteristics of the invading epithelium, and the stroma associated responses. Tangential sectioning, crush and cautery artifacts, and associated inflammatory infiltrate are commonly encountered problems and the source of pitfalls. In this review, we outline diagnostic criteria, common pitfalls, and different histological patterns of invasion into the lamina propria. Current recommendations on reporting of biopsy and transurethral resection specimens, molecular biomarkers, clinical implications of T1 cancer diagnosis and recent developments on the T1 substaging are also discussed. Most T1 bladder cancer patients will benefit from conservative management after restaging transurethral resection of bladder and bacillus Calmette-Guérin maintenance. Patients with high risk features, such as concurrent urothelial carcinoma in situ, increased depth of invasion, lymphovascular invasion, and variant histology among others, should be considered for early cystectomy.

Response to Neoadjuvant Chemotherapy and Survival in Micropapillary Urothelial Carcinoma: Data From a Tertiary Referral Center and the Surveillance, Epidemiology, and End Results (SEER) Program

BACKGROUND

Micropapillary urothelial carcinoma (MPC) is a rare urothelial carcinoma variant with conflicting data guiding clinical practice. In this study, we explored oncologic outcomes in relation to neoadjuvant chemotherapy (NAC) in a retrospective cohort of patients with MPC, alongside data from Surveillance, Epidemiology, and End Results (SEER)-Medicare.

PATIENTS AND METHODS

We retrospectively identified patients with MPC or conventional urothelial carcinoma (CUC) without any variant histology undergoing radical cystectomy (RC) in our institution (2003-2018). SEER-Medicare was also queried to identify patients diagnosed with MPC (2004-2015). Clinicopathologic data and treatment modalities were extracted. Overall survival (OS) was estimated with the Kaplan-Meier method. Mann-Whitney-Wilcoxon and chi-square tests were used for comparative analysis and Cox regression for identifying clinical covariates associated with OS.

RESULTS

Our institutional database yielded 46 patients with MPC and 457 with CUC. In SEER-Medicare, 183 patients with MPC were identified, and 63 (34%) underwent RC. In the institutional cohort, patients with MPC had significantly higher incidence of cN+ (17% vs. 8%), pN+ stage (30% vs. 17%), carcinoma-in-situ (43% vs. 25%), and lymphovascular invasion (30% vs. 16%) at RC versus those with CUC (all P < .05). Pathologic complete response (ypT0N0) to NAC was 33% for MPC and 35% for CUC (P = .899). Median OS was lower for institutional MPC versus CUC in univariate analysis (43.6 vs. 105.3 months, P = .006); however, MPC was not independently associated with OS in the multivariate model. Median OS was 25 months in the SEER MPC cohort for patients undergoing RC, while NAC was not associated with improved OS in that group.

CONCLUSION

Pathologic response to NAC was not significantly different between MPC and CUC, while MPC histology was not an independent predictor of OS. Further studies are needed to better understand biological mechanisms behind its aggressive features as well as the role of NAC in this histology variant.

Micropapillary urothelial carcinoma of urinary bladder displays immunophenotypic features of luminal and p53-like subtypes and is not a variant of adenocarcinoma

OBJECTIVES

Micropapillary urothelial carcinoma of the urinary bladder (MPUC) is a rare variant of urothelial carcinoma which has aggressive clinical characteristics. The objective is to investigate the molecular subtypes of MPUC and the impact to the clinical outcome and determine whether MPUC represents a variant of adenocarcinoma.

MATERIALS AND METHODS

We evaluated surrogate immunohistochemical markers of luminal, basal, and p53-like subtypes and correlated with prognosis and the expression of markers related to bladder adenocarcinoma and glandular differentiation in 56 cases of MPUC (10 cases of transurethral resection and 46 cases of radical cystectomy). Biomarker expression in co-existing conventional urothelial carcinoma was also analyzed. Cox regression analysis was performed to study the impact of molecular subtype on the clinical outcome.

RESULTS

Thirty-four cases (61%) met criteria for the luminal subtype. Twenty-two cases (39%) displayed a p53-like subtype. In contrast, 40/56 (71%) cases of coexisting conventional urothelial carcinoma were classified as luminal subtype and 16/56 (29%) cases were designated as p53-like subtype. There was no significant survival difference between luminal subtype and p53-like subtype. CDX2, villin, and cadherin 17 were negative in all cases. MUC1 was strongly and diffusely expressed in the stroma-facing surface of MPUC tumor cells in all the cases.

CONCLUSIONS

Our findings suggest that MPUC possesses characteristics of luminal and p53-like subtypes, and does not harbor phenotypic features of the basal subtype. There is no significant difference in the prognosis between luminal and p53-like subtype MPUC. MPUC is not a variant of adenocarcinoma and does not represent a form of glandular differentiation, in contrast to other organ sites.

Diagnostic and prognostic roles of CK20 in the pathology of urothelial lesions. A systematic review

Cytokeratin 20 (CK20) is one of the most common immunohistochemical markers in the routine practice of a pathology lab, as biopsies from the urinary tract encompass a wide spectrum of lesions which may pose issues in their detection and classification. In this review, we aim to outline the diagnostic accuracy and prognostic value of CK20 in flat urothelial lesions, papillary non-invasive and invasive urothelial carcinoma, molecular subgroups and variant histology, and we briefly discuss its limitations and potential pitfalls.

Intestinal Trefoil Factor 3 Alleviates the Intestinal Barrier Function Through Reducing the Expression of TLR4 in Rats with Nonalcoholic Steatohepatitis

BACKGROUND

Previous studies have reported that nonalcoholic steatohepatitis (NASH) is relevant to intestinal mucosal barrier dysfunction.

AIM OF THE STUDY

To investigate the effects of intestinal trefoil factor 3 (TFF3) on intestinal barrier function and endotoxin/toll-like receptor 4(TLR4) expression in NASH rats.

METHODS

Sixty NASH rats were divided into control, NASH and NASH-TFF3 treated group. Intestinal permeability, serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), endotoxin (ET), diamine oxidase (DAO) and liver index were examined. HE and PAS staining were performed to observe the histopathology of liver and terminal ileum. Expression of TFF3 and occludin were detected by immunohistochemical staining. mRNA and protein expression of TLR4, nuclear factor-κB (NF-κB), Mucin-2(Muc2) were detected by RT-qPCR and Western Blot. Interleukin (IL) -1β and IL-10 levels in the ileum were measured by ELISA.

RESULTS

In NASH group, levels of AST, ALT, ET, DAO, NAS, liver index and intestinal permeability were higher while occludin expressions were lower than control and NASH-TFF3 treated groups (p <0.05). Histopathology examination showed pathological damages of liver and ileum were alleviated in NASH-TFF3 treated group. NASH-TFF3 treated group had decreased expression levels of TLR4 and NF-κB and increased expression levels of Muc2 than NASH group. Besides, NASH group showed increased IL-1β and IL-10 levels compared with control group. NASH-TFF3 treated group showed decreased IL-1β level however increased IL-10 level compared with NASH group.

CONCLUSION

Recombinant human TFF3 (rhTFF3) can reduce the expression of TLR4, reduce intestinal permeability, alleviate liver damage and thus may play a therapeutic role in the treatment of NASH rats.

Prognostic and therapeutic role of HER2 expression in micropapillary carcinoma of the bladder

Micropapillary carcinoma of the bladder (MPBC) is a variant type of infiltrating urothelial carcinoma, which portends a poor biological behavior in terms of disease stage at first diagnosis and clinical outcome; its peculiar morphology raises issues concerning the ability of tumor detection by imaging techniques and proper biopsy procedure, and the appropriate treatment for non-muscle infiltrating and muscle-infiltrating MPBC remains a matter of debate. On the basis of its established prognostic and therapeutic role in breast and gastro-esophageal cancer in the first instance, the human epidermal growth factor receptor-2 (HER2) has been investigated in selected case series of MPBC over the last 10 years. The aim of the present review was to summarize the existing evidence on HER2 status in MPBC, and to discuss its present and future utility in risk assessment and treatment choice of this uncommon, yet aggressive, disease.

Rare Lesions and Tumors of the Urinary Bladder. Selected Issues

Morphological variants of urothelial cancer have been recently described. The timely identification and recognition of these histological variants should avoid their misinterpretation as benign lesions. We emphasize the peculiar features of these variants because some may require different/specific therapeutic approaches.

Clinicopathological implications to micropapillary bladder urothelial carcinoma of the presence of sialyl Lewis X-decorated mucin 1 in stroma-facing membranes

OBJECTIVES

Bladder urothelial carcinoma (UC) comprises more than 90% of all bladder cancers. Among several UC variants, micropapillary UC (MPUC) is a rare one with high potential for lymphovascular invasion and subsequent lymph node metastasis. Histologically, MPUC is characterized by the presence of small papillary carcinoma cell clusters surrounded by lacunar spaces. Immunohistochemically, the outer circumference of these clusters, that is, the stroma-facing membrane of carcinoma cells, is reportedly almost invariably positive for mucin 1 (MUC1) protein and to a lesser extent for sialyl Lewis X (sLeX) carbohydrates; however, the clinicopathological implications of these expression patterns have not been fully investigated.

MATERIALS AND METHODS

We performed immunohistochemical analysis of MPUC (n = 11) and conventional UC (n = 57) for MUC1 and sLeX to determine whether these factors immunolocalized. Dual immunofluorescence staining was also carried out to assess MUC1 and sLeX colocalization. We also performed Western blot analysis of Chinese hamster ovary cells misexpressing both recombinant epitope-tagged MUC1 and glycosyltransferases enabling sLeX biosynthesis.

RESULTS

MPUC samples preferentially exhibited both MUC1 protein and sLeX carbohydrate expression on the stroma-facing membrane of carcinoma cells. Based on univariate analysis, MUC1 expression in that pattern was positively correlated with tumor extension, lymphovascular invasion, lymph node metastasis, disease stage, and relatively poor patient prognosis. A comparable sLeX expression pattern also correlated positively with tumor extension and nodal metastasis. Based on multivariate analysis, localization of MUC1 and sLeX on the stroma-facing side of the membrane was positively correlated with lymph node metastasis.

CONCLUSIONS

Overall, our immunofluorescence findings as well as immunoprecipitation analyses of Chinese hamster ovary cell transfectants strongly suggest that MUC1 is a potential scaffold protein for sLeX carbohydrates in MPUC. Both MUC1 and sLeX may cooperatively contribute to MPUC histogenesis and clinicopathological characteristics.

Detection and Clinical Significance of Circulating Tumor Cells in Patients Undergoing Radical Cystectomy for Urothelial Bladder Cancer

INTRODUCTION

Estimation of prognosis is patients undergoing radical cystectomy is often unreliable, as occult disease remains undetected by conventional diagnostic tools. The purpose of this study was to evaluate the feasibility and the clinical significance of a polymerase chain reaction assay to detect cytokeratin 7 (CK7) mRNA expression in peripheral blood cells of patients undergoing radical cystectomy for clinically nonmetastatic bladder cancer.

PATIENTS AND METHODS

From 2005 to 2009, 59 patients undergoing radical cystectomy and pelvic lymph node dissection were prospectively investigated. Peripheral blood was collected prior to surgery, and a nested polymerase chain reaction assay was developed to identify patients with circulating cells expressing CK7 mRNA. Preoperative, histopathologic data and clinical outcome were compared with CK7 findings.

RESULTS

CK7 expression was detected in 23 (38.9%) of 59 patients and correlated to T stage and lymph node status. After a median follow-up of 42 months, 29 patients experienced a recurrence, whereas 36 died. The presence of CK7-positive cells was significantly associated with an increased risk for recurrence and decreased survival as compared with patients who were CK7-negative (P < .001 and P < .001, respectively; hazard ratios of 8.77 and 5.2 for recurrence and overall death, respectively). The detection of CK7-positive cells was an independent predictor of recurrence and death in a multivariable analysis.

CONCLUSION

The detection of CK7 mRNA in the circulating cells of patients undergoing radical cystectomy for urothelial cancer identifies those with significantly increased risk of cancer recurrence and death.

High prevalence of TERT promoter mutations in micropapillary urothelial carcinoma

Somatic activating mutations in the promoter of the telomerase reverse transcriptase (TERT) gene are the most common genetic alterations in urothelial carcinoma (UC) of the bladder and upper urinary tract. Little is known, however, about TERT-mutation status in the relatively uncommon but clinically aggressive micropapillary (MPC) variant. We evaluated the presence of TERT promoter mutations in MPC of the bladder and upper urinary tract. A retrospective search of our archives for MPC and UC with micropapillary features (2005-2014) was performed. All slides were reviewed to confirm the histologic diagnosis. Thirty-three specimens from 31 patients had FFPE blocks available for DNA analysis and were included in the study. Intratumoral areas of non-micropapillary histology were also evaluated when present. Samples were analyzed with Safe-SeqS, a sequencing error reduction technology, and sequenced using the Illumina MiSeq platform. TERT promoter mutations were detected in all specimens with pure MPC (18 of 18) and UC with focal micropapillary features (15 of 15). Similar to conventional UC, the predominant mutations identified occurred at positions -124 (C228T) (85 %) and -146 (C250T) (12 %) bp upstream of the TERT ATG start site. In heterogeneous tumors with focal variant histology, intratumoral concordant mutations were found in variant (MPC and non-MPC) and corresponding conventional UC. We found TERT promoter mutations, commonly found in conventional UC, to be frequently present in MPC. Our finding of concordant intratumoral mutational alterations in cases with focal variant histology lends support to the common oncogenesis origin of UC and its variant histology.

The Natural History, Treatment Pattern, and Outcomes of Patients With Micropapillary Bladder Carcinoma

OBJECTIVE

Micropapillary bladder carcinoma (MPBC) is a rare variant of urothelial cancer. Most literature on MPBC is from case series reports. This study's objective was to examine the epidemiology, natural history, and prognostic factors of MPBC using a population-based registry, in addition to a literature review.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database identified 98 histologically confirmed MPBC patients from 2001 and 2007. In addition, 213 MPBC cases were identified in published literature. The clinical, demographic characteristics, treatment, and survival outcomes were compared between these 2 cohorts.

RESULTS

Among patients identified in SEER, MPBC accounted for approximately 0.01% of primary bladder tumors, with the median age of 72 years (range, 26 to 95 y). Among the MPBC cases, 56.1% had muscle invasive disease, 75.5% had poor or undifferentiated histology, and 30.6% underwent a radical or partial cystectomy. The 1-, 3-, and 5-year overall survival rates for the SEER cohort were estimated at 84.5%, 57.3%, and 42.3%, respectively. Using multivariate analysis, tumor stage and marital status were the most significant predictors for cancer-specific survival. When comparing published single-institution studies to the SEER cohort, significant differences existed in demographic characteristics including age at diagnosis, male-to-female ratio, tumor stage, cystectomy treatment, and survival outcomes, likely reflecting differences in practice patterns.

CONCLUSIONS

This is the first population-based study to analyze MPBC's epidemiology, tumor characteristics, and survival rates. Emphases on early detection, cystectomy, and multimodality in treatment are needed.

Pulmonary metastasis in a patient with simultaneous bladder cancer and relapsing granulomatosis with polyangiitis

Patient: Male, 70

Final Diagnosis: Metastatic micropapillary urothelial carcinoma

Symptoms: Dry cough • dyspnea • hematuria

Medication: Cyclophosphamide

Clinical Procedure: Pulmonary wedge resection

Specialty: Pulmonology

Uroplakin II is a more sensitive immunohistochemical marker than uroplakin III in urothelial carcinoma and its variants

OBJECTIVES

Uroplakin (UP) II and UPIII are highly specific immunohistochemical markers for urothelial differentiation. Here we studied the sensitivity of UPII and UPIII in conventional and variant urothelial carcinomas (UCs).

METHODS

Immunohistochemical staining for UPII and UPIII was performed on tissue microarray slides, including 105 conventional bladder UCs (BUCs), 90 upper urinary tract UCs (UUTUCs), and 47 micropapillary, 16 plasmacytoid, 22 small cell carcinoma, and 41 sarcomatoid UC variants.

RESULTS

UPII expression was significantly higher than UPIII expression in conventional BUC (44% vs 17%, P < .001) and UUTUC (67% vs 46%, P = .045). UPIII expression was significantly higher in UUTUC than in BUC (P < .001). In UC variants, UPII expression was significantly higher than UPIII expression in micropapillary (91% vs 25%, P < .001), plasmacytoid (63% vs 6%, P < .001), and sarcomatoid (29% vs 5%, P = .032) variants. Only rare cases of the small cell carcinoma variant had focal UPII and UPIII expression. Compared with conventional UC, the sarcomatoid variant had significantly lower UPII expression, whereas the micropapillary variant had significantly higher UPII expression (P < .001).

CONCLUSIONS

UPII demonstrates a significantly higher sensitivity than UPIII in conventional and variant UCs. Thus, UPII is a more valuable marker than UPIII in immunohistochemical analyses for confirming the urothelial origin of carcinomas.

The Application of Immunohistochemical Biomarkers in Urologic Surgical Pathology

Context

Tumors of the genitourinary tract can be diagnostically challenging, particularly in core biopsies and cystoscopic biopsies with limited material. Immunohistochemistry is a valuable tool to use when morphology alone is insufficient for diagnosis.

Objectives

To review tumors and benign lesions of the kidney, urinary bladder, prostate gland, testis, and paratesticular structures with an emphasis on difficult differential diagnoses, as well as staining patterns in normal tissue. Recommended immunohistochemical stain panels are discussed that can assist in the diagnostic workup.

Data Sources

Review of current literature.

Conclusions

Immunohistochemistry is a valuable tool, assisting in the diagnosis of problematic tumors and benign lesions of the genitourinary tract.

Invasive micropapillary carcinoma of the extrahepatic bile duct and its malignant potential

Invasive micropapillary carcinoma (IMPC) was originally described as a distinctive type of invasive carcinoma in the breast, but it has not been recognized as a histological type of the extrahepatic bile duct cancer. The present study demonstrated clinicopathological features and patient prognosis of IMPC. We examined histological reviews of 93 consecutive cases of the extrahepatic bile duct cancer and identified 13 cases which included IMPC component. The component of IMPC ranged from 5 to 60% of the primary tumor tissue, which was mainly detected at the invasive front of the tumor. Of the 13 cases, 12 (92.3%) carcinomas with IMPC showed lymph node metastasis more frequently compared to conventional adenocarcinoma (39.2%, P<0.001). Presence of IMPC component was significantly associated with poor overall survival (P=0.003). In conclusion, extrahepatic bile duct carcinoma with IMPC component showed significant lymphatic invasion, lymph node metastasis, and resulted in poor prognosis.

Immunohistochemical evaluation of novel and traditional markers associated with urothelial differentiation in a spectrum of variants of urothelial carcinoma of the urinary bladder

Data on immunohistochemical expression of novel and traditional urothelial markers in the wide range of urothelial carcinoma variants have so far been very limited. In this study, whole tissue sections from 130 bladder urothelial carcinoma and variants were stained with a panel of novel and traditional immunomarkers supportive of urothelial lineage. The positivity rates were as follows: (a) urothelial carcinomas with or without divergent differentiation: GATA3 (50%), S-100P (86%), uroplakin III (20%), thrombomodulin (40%), cytokeratin 7 (CK7) (80%), CK20 (55%), p63 (87%), and high molecular weight cytokeratin (HMCK) (89%); (b) urothelial carcinoma variants (micropapillary, plasmacytoid, nested, clear cell, and microcystic): GATA3 (88%), S-100P (96%), uroplakin III (33%), thrombomodulin (49%), CK7 (95%), CK20 (61%), p63 (69%), and HMCK (96%); and (c) undifferentiated carcinomas (lymphoepithelioma-like carcinoma, small cell carcinoma, sarcomatoid carcinoma and carcinoma with rhabdoid and giant cells): GATA3 (28%), S-100P (31%), uroplakin III (0%), thrombomodulin (22%), CK7 (50%), CK20 (3%), p63 (50%), and HMCK (49%). In urothelial carcinoma with squamous differentiation, GATA3 expression was lower (20%) in contrast to p63 and S-100P. In urothelial carcinoma with glandular differentiation, GATA3 (50%) and p63 (60%) expression was lower than S-100P (100%). p63 expression was relatively lower in micropapillary (54%) and plasmacytoid (50%) variants compared with the other urothelial carcinoma variants. This study provides comprehensive data for novel and traditionally used markers to support urothelial lineage in urothelial carcinoma variants. Our findings show that GATA3, S-100P, CK7, CK20, HMCK, and p63, in the appropriate differential diagnostic setting, are useful to support urothelial lineage of variant morphologies.

Outcome of patients with micropapillary urothelial carcinoma following radical cystectomy: ERBB2 (HER2) amplification identifies patients with poor outcome

Micropapillary urothelial carcinoma exhibits amplification of the human epidermal growth factor receptor, ERBB2(HER2), and overexpression of the ERBB2 protein product. The clinical significance of this has yet to be established. The objective of this study was to examine ERBB2 amplification and protein expression in micropapillary urothelial carcinoma and stage-matched typical urothelial carcinoma treated by radical cystectomy to assess the frequency of amplification and protein expression, and to determine the association with cancer-specific survival. Pathologic material and data from patients undergoing cystectomy at Mayo Clinic between 1980 and 2008 were reviewed. ERBB2 amplification by fluorescence in situ hybridization (FISH) and protein expression by immunohistochemistry were assessed. Univariate and multivariate Cox proportional hazards regression models were used to evaluate for associations of ERBB2 amplification and protein expression with survival. ERBB2 amplification was identified in 9 (15%) of 61 micropapillary carcinomas compared with 9 (9%) of 100 urothelial carcinomas. In patients with micropapillary carcinoma, ERBB2 amplification was associated with a nearly threefold increased risk of cancer death. ERBB2 amplification (hazard ratio 4.3; P=0.0008) remained associated with an increased risk of death from bladder cancer among patients with micropapillary urothelial carcinoma on multivariate analysis. The association of cancer-specific survival and ERBB2 amplification was not seen in patients with urothelial carcinoma. ERBB2 immunohistochemistry correlated with ERBB2 amplification but there was no association of ERBB2 protein expression and survival. ERBB2 amplification is more frequent in micropapillary urothelial carcinoma than typical urothelial carcinoma, and patients with micropapillary carcinoma who have ERBB2 amplification have worse cancer-specific survival than those who do not. Identification of ERBB2 amplification in micropapillary carcinoma could provide important prognostic information and possibly provide a role for ERBB2 targeted therapy.

Micropapillary carcinoma of the urinary tract: a cytologic study of urine and fine-needle aspirate samples

OBJECTIVE

Micropapillary carcinoma (MPC) is an aggressive variant of urothelial carcinoma that needs early and specific recognition. In order to determine whether this tumor variant can be recognized with cytology, we evaluated a large cytohistological series.

STUDY DESIGN

It was a retrospective cytohistological correlation study including 20 patients with MPC. Only those cases in which the tumor exhibited >50% of micropapillary growth were selected. Twenty exfoliative urine specimens and four needle aspirates from lymph node metastases were reviewed.

RESULTS

On histology, 14 cases were infiltrative, while 6 were exclusively superficial. Cytology was characterized by numerous small, cohesive groups and single neoplastic cells. Pseudopapillae were present in 17 cases and in 9 they were a relevant finding. Morules were present in 15 cases. Isolated microacini were seen in 14 cases. Infiltrative tumors showed more neoplastic groups. Cellular atypia was prominent in 17 cases. In 15 cases, a cytologic diagnosis of urothelial carcinoma was made. One case was diagnosed as adenocarcinoma. The remaining 4 cases were considered suspicious of malignancy.

CONCLUSIONS

The peculiar morphology of MPC of the urinary tract is partially reflected on cytology, allowing in some cases a specific recognition. This is important since the aggressive behavior of this neoplasm needs rapid management and treatment.

Micropapillary variant of embryonal carcinoma: clinicopathological correlation and histochemical study

Micropapillary pattern of growth (MPG) of carcinoma is a unique morphologic pattern. It is uncommon but a predictor of poor outcome. MPG has not been described in any germ cell tumor, most notably embryonal carcinoma, which may have papillary configuration. In this study, we reviewed 25 primary testicular germ cell tumors (pure or mixed) containing embryonal carcinoma and 2 lymph node metastases with embryonal carcinoma. Five of the 25 primary cases demonstrated MPG. With available clinical information, 3/3 (100%) cases with MPG and 5/12 (42%) cases without MPG showed evidence of metastases. The 2 lymph node metastases contained predominantly MPG. At metastasis, the median tumor size in primary tumors with MPG was significantly smaller than in those without MPG. Reticulum staining was negative in the regions of MPG and positive for other coexisting non-micropapillary growth patterns in all the 6 embryonal carcinomas. In conclusion, we described MPG in embryonal carcinoma. Although limited by the number of cases, our clinicopathological correlation results raised the possible association of the presence of MPG to the high-rate metastasis of embryonal carcinoma, similar to that seen in other carcinomas with MPG. It is therefore of importance to document this variant growth pattern if present in embryonal carcinoma. We also demonstrated that reticulum is a useful negative marker for identification of MPG.

Low Grade Micropapillary Urothelial Carcinoma, Does It Exist? - Analysis of Management and Outcomes from the Surveillance, Epidemiology and End Results (SEER) Database

Objective: To elucidate the oncologic behavior of Micropapillary Urothelial Bladder Carcinoma (MPBC), a rare aggressive variant histology.

Methods: All MPBC patients in SEER 17 database were compared with those with traditional urothelial carcinoma (UC). Kaplan-Meier curves were used to determine OS and CSS. A Cox proportional hazards model (CPH) was constructed to test the effect of covariates on outcomes.

Results: From 2001-2008, 120 MPBC patients were identified, 0.1% of all bladder cancer. MPBC presented with more high grade (86.1% vs. 38.7%, p<0.0001) and more high stage disease (40.8% NMI vs. 90.4% NMI, p < 0.0001) than UC. Low grade (LG) NMI MPBC had worse OS and CSS compared to LG UC (p=0.0037, p<0.0001 respectively), and did no better than high grade (HG) NMI MPBC. No difference was detected between HG NMI MPBC and HG NMI UC pts. A CPH model controlling for stage, grade, treatment, age, race, and sex detected no significant survival difference in MPBC vs. UC (HR 1.04, p=0.7966). For NMI MPBC (n=49), only 4 patients underwent definitive therapy, of whom none died of disease. However, in those not receiving definitive therapy (n=45), 7 cancer specific deaths occurred (15.6%).

Conclusion: Controlling for stage and grade, no survival difference could be detected between MPBC and UC. Low grade NMI MPBC behaved similarly to both high grade MPBC and high grade UC. We propose that all MPBC (regardless of grade) be managed as high grade disease, and that strong consideration for definitive therapy should be given in all cases.

Micropapillary urothelial carcinoma: Cytologic features in a retrospective series of urine specimens

Background:

The micropapillary variant of urothelial carcinoma (uPC) is a rare variant of urothelial carcinoma that carries a poor prognosis. Definitive surgery may represent optimal management of low stage tumors. Urine cytology is indispensable in the screening and follow-up of urinary tract cancer. However, cytopathological criteria for diagnosis of uPC and its differentiation from conventional urothelial carcinoma (CUC) are not well-defined.

Materials and Methods:

Twenty-five cases of histologically confirmed micropapillary uPC from 21 patients were compared to 25 cases of histologically confirmed high-grade CUC.

Results:

In uPC cases, cell clusters were identified in 13 of 25 specimens from 10 patients. Six of the 13 specimens containing cell clusters corresponded to surgical pathology specimens in which micropapillary carcinoma accounted for at least 50% of total carcinoma. In contrast, only 1 of the 12 urine specimens devoid of cell clusters corresponded to surgical specimens in which micropapillary carcinoma accounted for at least 50% of total carcinoma. Cytomorphologic features of urinary specimens from patients with histologically confirmed micropapillary carcinoma were generally similar to those from patients with high-grade CUC, making it difficult to distinguish these entities in exfoliative urine specimens.

Conclusions and Summary:

Further investigation of the core cytopathological characteristics of uPC is warranted to refine its diagnostic criteria by exfoliative urine cytology.

Plasmacytoid variant of bladder cancer defines patients with poor prognosis if treated with cystectomy and adjuvant cisplatin-based chemotherapy

Background

Since the definition of different histologic subtypes of urothelial carcinomas by the World Health Organization (WHO) 2004 classification, description of molecular features and clinical behavior of these variants has gained more attention.

Methods

We reviewed 205 tumor samples of patients with locally advanced bladder cancer mainly treated within the randomized AUO-AB05/95 trial with radical cystectomy and adjuvant cisplatin-based chemotherapy for histologic subtypes. 178 UC, 18 plasmacytoid (PUC) and 9 micropapillary (MPC) carcinomas of the bladder were identified. Kaplan Meier analysis and backward multivariate Cox’s proportional hazards regression analysis were performed to compare overall survival between the three histologic subtypes.

Results

Patients suffering from PUC have the worst clinical outcome regarding overall survival compared to conventional UC and MPC of the bladder that in turn seem have to best clinical outcome (27.4 months, 62.6 months, and 64.2 months, respectively; p=0.013 by Kaplan Meier analysis). Backward multivariate Cox´s proportional hazards regression analysis (adjusted to relevant clinicopathological parameters) showed a hazard ratio of 3.2 (p=0.045) for PUC in contrast to patients suffering from MPC.

Conclusions

Histopathological diagnosis of rare variants of urothelial carcinoma can identify patients with poor prognosis.

Noninvasive micropapillary urothelial carcinoma: a clinicopathologic study of 18 cases

Noninvasive micropapillary urothelial carcinoma consists of slender tufts of urothelial carcinoma lacking fibrovascular cores analogous to ovarian papillary serous tumors of borderline malignancy. Eighteen noninvasive micropapillary urothelial carcinoma cases were identified from the Pathology Department of The Johns Hopkins Hospital (2000-2011). Patients lacked history of invasive urothelial carcinoma. Two patterns of noninvasive micropapillary urothelial carcinoma were identified: (1) as a variant of noninvasive high-grade papillary urothelial carcinoma (high-grade papillary urothelial carcinoma/micropapillary urothelial carcinoma) (n = 13 cases) and (2) as a variant of urothelial carcinoma in situ (carcinoma in situ/micropapillary urothelial carcinoma) (n = 5 cases with 2 of these patients also having high-grade papillary urothelial carcinoma/micropapillary urothelial carcinoma). Of 18 patients, 16 (88%) were male with a mean age of 71.8 years (range, 54-87 years). Of the 12 patients initially treated with surveillance, Bacillus-Calmette Guérin, or intravesical chemotherapy, 4 did not recur and were without evidence of disease at 6, 21, 24, and 39 months. Four patients experienced recurrences with 3 of them without evidence of disease at 36, 52, and 72 months and with the fourth whose last follow-up was at 84 months when recurrence occurred. One patient is alive at 11 months with disease, and 1 died of other causes at 1 month. Two patients progressed to pT2 and pT3 disease at 5 and 21 months, respectively. It is critical to differentiate and clearly specify in pathology reports whether micropapillary urothelial carcinoma is invasive or noninvasive because invasive micropapillary urothelial carcinoma is an aggressive disease with a high degree of understaging, whereas some cases of noninvasive micropapillary urothelial carcinoma are not necessarily associated with an adverse outcome.

Lymphovascular Invasion in Micropapillary Urothelial Carcinoma: A Study of 22 Cases

Context.—Micropapillary urothelial carcinoma (MPUC) is a known aggressive variant of urothelial carcinoma. However, the reasons for its aggressiveness remain unclear.

Objective.—To investigate the frequency of lymphovascular invasion in 22 cases of MPUC.

Design.—Consecutive tissue sections were stained with D2-40 and CD34 to highlight lymphovascular channels associated with MPUC. Spaces containing tumor cells were scored as positive for lymphovascular invasion if the staining pattern on immunohistochemistry was distinct and circumferential.

Results.—Of 22 cases, 21 (95%) had lymphovascular invasion on immunohistochemical staining, with 91% lymphatic invasion and 4% vascular invasion. Interestingly, 8 cases were originally signed out as negative for lymphovascular invasion on the basis of hematoxylin-eosin–stained sections; of these, 7 (88%) had focal lymphovascular invasion evident on immunohistochemical staining.

Conclusions.—Our results confirm that micropapillary lacunae are not lymphovascular channels. However, nearly all MPUC tumors (95% in this series) have evidence of lymphovascular invasion by immunohistochemical analysis. Our data support the use of micropapillary features as a morphologic marker for lymphovascular invasion and MPUC as an adverse histologic type of urothelial carcinoma.

Micropapillary variant of urothelial carcinoma

Micropapillary carcinoma (MPC) of urinary tract is an uncommon variant of urothelial carcinoma with significant diagnostic and prognostic implications. Though MPC shows characteristic microscopic features, there exists interobserver variability and also it needs to be differentiated from the metastasis from other organs. The prognosis is generally poor, depending on the proportion of the micropapillary component in some reports. Early cystectomy in cases with only lamina propria invasion may be indicated according to recent studies. This review outlines the general features of this entity and briefly comments on the controversies and the recent development.

Neoadjuvant systemic therapy or early cystectomy? Single-center analysis of outcomes after therapy for patients with clinically localized micropapillary urothelial carcinoma of the bladder

OBJECTIVES

To analyze the treatment outcomes of patients with micropapillary bladder cancer (MPBC). MPBC is a rare variant of urothelial carcinoma with aggressive clinical behavior. Radical cystectomy is considered the standard approach for treatment of patients with localized disease; however, the role of perioperative systemic therapy has been poorly defined.

MATERIAL AND METHODS

A retrospective review identified 38 consecutive patients who had been treated at our institution for MPBC from 2000 to 2010. The patient data were analyzed for the pre- and postoperative clinicopathologic features, treatment course, and cancer-specific survival.

RESULTS

The median follow-up of surviving patients after cystectomy was 17 months (range 2-75). At the initial transurethral biopsy, 28 patients (74%) had clinical Stage T2N0 or less. In this group, 26 (93%) of 28 were upstaged to nonorgan-confined and/or lymph node-positive disease. Overall, 32 patients (86%) had evidence of lymph node metastasis on the final pathologic examination. All patients with cTis-T1 who had undergone initial bladder-sparing therapy with bacille Calmette-Guérin had pathologically advanced disease at cystectomy. All 15 patients who had received perioperative cisplatin-based chemotherapy died of metastatic disease. The 5-year overall survival rate was 40% (95% confidence interval 16-64).

CONCLUSIONS

MPBC is an aggressive disease with a high likelihood of regional lymph node metastasis at the initial presentation. Although radical cystectomy plays a critical role in treatment, systemic neoadjuvant chemotherapy might be a more appropriate strategy than immediate cystectomy. Because of the poor response to current chemotherapy agents, the development of new and effective drugs for this subset of patients could be needed.