Micropapillary variant of transitional cell carcinoma of the urinary bladder. Histologic pattern resembling ovarian papillary serous carcinoma

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.

Non-invasive papillary urothelial carcinoma with 'micropapillary' architecture: clinicopathological study of 18 patients emphasising clinical outcomes

AIMS

Invasive micropapillary carcinoma is a recognised aggressive urothelial carcinoma variant. One prior study focusing on non-invasive (pTa) high-grade papillary urothelial carcinoma with micropapillary architecture has been reported.

METHODS AND RESULTS

We collected bladder transurethral resection specimens showing non-invasive high-grade papillary urothelial carcinoma with non-hierarchical secondary papillae lacking fibrovascular cores (i.e. micropapillary architecture). Cases with any invasive component or any prior history of invasive urothelial carcinoma were excluded. Twenty cases were identified from 16 male and two female patients (aged 55-86 years). Micropapillary architecture comprised from 10 to 95% (mean = 31%), but non-invasive cribriform (15 cases, comprising 5-60%, mean = 19%) and villoglandular patterns (nine cases, comprising 5-60%, mean = 24%) were commonly admixed. Treatment data were available for 16 patients: surveillance (n = 13), cystoprostatectomy (n = 1), BCG plus mitomycin (n = 1) and BCG (n = 1). Follow-up data were available from 16 patients (range = 1-128 months, mean = 50 months): 13 patients had no new occurrences to date (81%), two had stage progression to pT1 papillary urothelial carcinoma (13%) with one dying of other causes, and one died of other causes with no evidence of disease (6%).

CONCLUSION

Non-invasive urothelial carcinomas with micropapillary architecture are often admixed with non-invasive cribriform and villoglandular patterns. Stage progression to lamina propria invasion in only two of 16 patients (13%) is not higher than expected for otherwise typical pTa high-grade urothelial carcinomas and no progression to invasive micropapillary carcinoma was identified, adding further support to the current World Health Organisation recommendation excluding use of the term 'micropapillary' for pTa urothelial carcinoma.

Micropapillary Versus Urothelial Carcinoma of the Urinary Bladder: Stage at Presentation and Efficacy of Chemotherapy Across All Stages-A SEER-based Study

BACKGROUND

Stage-specific guideline recommendations are lacking for chemotherapy in micropapillary carcinoma of the urinary bladder (MCUB).

OBJECTIVE

To test the efficacy of stage-specific chemotherapy for MCUB.

DESIGN, SETTING, AND PARTICIPANTS

Within the Surveillance, Epidemiology and End Results (SEER) registry (2001-2016), we identified patients with MCUB and pure urothelial carcinoma of the urinary bladder (UCUB) of all stages.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Kaplan-Meier survival analyses and multivariate Cox regression models were used to determine cancer-specific mortality (CSM) in addition to power analyses.

RESULTS AND LIMITATIONS

Of 210 491 patients of all stages, 518 (0.2%) harboured MCUB versus 209 973 (99.8%) UCUB. Stage at presentation was invariably higher in MCUB than in UCUB patients. Of the MCUB patients, 223 (43.1%) received chemotherapy versus 42 921 (20.4%) of the UCUB patients. In MCUB patients, chemotherapy improved CSM-free survival significantly in metastatic stage (hazard ratio [HR] 0.36, p = 0.04). Longer median CSM-free survival was also associated with chemotherapy use in addition to radical cystectomy (RC) versus RC alone in non-organ-confined MCUB (HR 0.69, p = 0.2). Additional power analyses revealed an underpowered comparison. Finally, no CSM difference was recorded in organ-confined MCUB according to the use of chemotherapy in addition to RC versus RC alone (HR 0.98, p = 1).

CONCLUSIONS

Stage at presentation was invariably higher in MCUB than in UCUB patients. Very important CSM reduction was associated with chemotherapy use in metastatic MCUB. A promising protective effect of perioperative chemotherapy might also be applicable to non-organ-confined MCUB, but without sufficient statistical power. Conversely, no association was recorded in organ-confined MCUB.

PATIENT SUMMARY

Patients with micropapillary carcinoma of the urinary bladder (MCUB) present in higher tumour stages than those with urothelial carcinoma of the urinary bladder. Chemotherapy for MCUB is effective in metastatic stages, but of no beneficial effect in organ-confined stage. In not-yet-metastatic but already non-organ-confined stages, we did not have enough observations to show a statistically significant protective effect of chemotherapy.

Role of tyrosine kinases in bladder cancer progression: an overview

Background

Bladder cancer (BCa) is a frequent urothelial malignancy with a high ratio of morbidity and mortality. Various genetic and environmental factors are involved in BCa progression. Since, majority of BCa cases are diagnosed after macroscopic clinical symptoms, it is required to find efficient markers for the early detection. Receptor tyrosine-kinases (RTKs) and non-receptor tyrosine-kinases (nRTKs) have pivotal roles in various cellular processes such as growth, migration, differentiation, and metabolism through different signaling pathways. Tyrosine-kinase deregulations are observed during tumor progressions via mutations, amplification, and chromosomal abnormalities which introduces these factors as important candidates of anti-cancer therapies.

Main body

For the first time in present review we have summarized all of the reported tyrosine-kinases which have been significantly associated with the clinicopathological features of BCa patients.

Conclusions

This review highlights the importance of tyrosine-kinases as critical markers in early detection and therapeutic purposes among BCa patients and clarifies the molecular biology of tyrosine-kinases during BCa progression and metastasis.

Variant morphology and random chromosomal integration of BK polyomavirus in posttransplant urothelial carcinomas

BK polyomavirus (BKPyV) causes major complications in solid organ transplant recipients but little is known about its role in the development of urothelial carcinoma (UC) during immunosuppression. Immunohistochemistry (IHC) screening for polyomavirus large T antigen (LTag) was performed in 94 micropapillary UC (MPUC), 480 unselected UC, 199 muscle invasive UC (including 83 UC with variant differentiation), 76 cases of plasmocytoid, nested and large nested UC and 15 posttransplant UC. LTag expressing UC were reevaluated regarding their histomorphological features and characterized by IHC for p53 and HER2, chromogenic in situ hybridization for HER2 and SNaPshot analysis of the TERT promoter and HRAS. Real-time PCR and next generation sequencing (NGS) were performed to search for BKPyV-DNA and for variants in the tumor and viral genomes. We detected five LTag expressing UC which were diagnosed between 2 and 18 years after kidney (n = 4) or heart (n = 1) transplantation. 89 MPUC without history of organ transplantation and overall 755 UC (including cases with variant histology) were LTag negative. Of the five LTag expressing UC, three were MPUC, one showed extensive divergent differentiation with Mullerian type clear cell carcinoma, and one displayed focal villoglandular differentiation. All five tumors had aberrant nuclear p53 expression, 2/5 were HER2-amplified, and 3/5 had TERT promoter mutations. Within the 50 most common cancer related genes altered in UC we detected very few alterations and no TP53 mutations. BKPyV-DNA was present in 5/5 UC, chromosomal integration of the BKPyV genome was detectable in 4/5 UC. Two UC with BKPyV integration showed small deletions in the BKPyV noncoding control region (NCCR). The only UC without detectable BKPyV integration had a high viral load of human herpesvirus 6 (HHV-6). Our results suggest that LTag expression of integrated BKPyV genomes and resulting p53 inactivation lead to aggressive high-grade UC with unusual, often micropapillary morphology.

Cytological, histological, and molecular characteristics of pure invasive micropapillary carcinoma of pancreas: A case report

INTRODUCTION

Pure invasive micropapillary carcinoma (IMPC) is a rare histologic subtype of pancreatic cancer which has a high propensity for lymph node metastasis and poor prognosis.

PATIENT CONCERNS

An 81-year-old woman was admitted to our institution with a 3-month history of back pain. Computed tomography of the abdomen and pelvis confirmed the presence of a low-density mass in the tail of the pancreas.

DIAGNOSIS

Endoscopic ultrasound-guided fine needle aspiration cytology (FNAC) from the pancreatic mass showed small tumor cell clusters with three-dimensional aggregates and morula-like structures. The tumor was diagnosed as adenocarcinoma with micropapillary features.

INTERVENTIONS

The patient underwent radical antegrade modular pancreatosplenectomy and regional lymph node dissection. Histological examination showed small clusters of tumor cells that were closely adhered to one another. The cells were located in empty stromal spaces mimicking lymphovascular channels. All tumor cells showed reverse polarity, resulting in an "inside-out" pattern. An extensive search was performed, and no typical ductal adenocarcinoma component was found. The tumor measured 1.5 × 1.3 cm and invaded into the peripancreatic fat tissue without adjacent organ invasion. One of the 12 regional lymph nodes showed metastasis. Ion Torrent next-generation sequencing identified missense mutations in KRAS, TP53, and SMAD4 using the Oncomine Comprehensive Panel version 1.

OUTCOMES

Twelve months following surgical resection the patient remained healthy with no evidence of recurrence at clinical follow-up.

LESSONS

This report highlights the diagnostic features and molecular characteristics of pure pancreatic IMPC and the challenges with diagnosis by FNAC. A centralized and collaborative accumulation of additional cases of pure IMPC could further elucidate its pathogenesis.

Prognostic values of the clinicopathological characteristics and survival outcomes in micropapillary urothelial carcinoma of the bladder: A SEER database analysis

Purpose

To study prognostic values of the clinicopathological characteristics and survival outcomes in micropapillary urothelial carcinoma (MPUC) of the urinary bladder.

Method

We used the national Surveillance, Epidemiology, and End Results database (2004‐2016) to compare MPUC with transitional cell carcinoma (TCC) and to investigate prognostic values of clinicopathological characteristics, as well as survival outcomes, in MPUC of the urinary bladder. A multivariable Cox proportional hazard model, subgroup analyses, and propensity score matching were used.

Results

In all, 519 patients with MPUC and 154 453 patients with TCC were enrolled. Compared with TCC, patients with MPUC had a higher rate of muscle invasive disease (P < .001), lymph node metastasis (P < .001), and distal metastasis (P < .001), as well as higher tumor grade (P < .001). According to the survival analyses, the MPUC group also had lower survival probability in both cancer‐specific mortality (CSM) (P < .0001) and overall mortality (OM) analyses (P < .0001). Cox proportional hazard regression showed that the MPUC group had a higher risk of OM (hazard ratios [HR] = 1.39, 95% confidence intervals [CI] = 1.22‐1.57, P < .0001), although the CSM (HR = 1.18, 95% CI = 1.00‐1.40, P = .0505) in that group was fair. In the subgroup analysis, only MPUC patients without distal metastasis faced a higher risk of CSM (HR = 1.33, 95% CI = 1.101.61, P < .0001).

Conclusions

Micropapillary urothelial carcinoma prognosis is poorer than that of TCC. Micropapillary urothelial carcinoma is an independent prognostic factor for OM in patients with urinary bladder cancer.

Transurethral resection of bladder and radical cystectomy: Concordance of histology. Are we good enough?

OBJECTIVE

Urothelial carcinoma (UC) is heterogeneous, and variant histologies (VH) are more frequent than initially reported. Reporting VH is recommended by several guidelines because of prognostic and therapeutic implications. We evaluated the concordance of VH between the first transurethral resections of the bladder (TURBs) and the following radical cystectomy (RC). This paper is the first to compare VH with a central pathology review between TURB and RC.

MATERIAL AND METHODS

In this retrospective study, we only included those patients who underwent TURB with VH and then RC between 01/2010 and 12/2013 at our institution. The presence of VH in both TURB and RC was assessed and compared according to the 2016 World Health Organization (WHO) classification by a central pathology review.

RESULTS

Among 110 patients who had the initial TURB/RC, 54 (49.1%) were diagnosed with VH, 48 (43%) had a single pattern, and six had (5%) multiple histological patterns. Squamous differentiation was the most common single VH (31%). Twenty patients with UC (18%) showed discordance between TURB and RC, especially in micropapillary versus nested (n=3) cases. Concordant histology between TURB/RC was seen in 82% of the cases.

CONCLUSION

Discrepancies can be seen between TURB and RC when reporting VH, which can be problematic for selection of therapy and management. TURB alone might be insufficient to evaluate the presence of VH, especially in VH with heavy therapeutic implications, such as micropapillary carcinomas. Nevertheless, concordance with a central review by an experienced uropathologist when applying the WHO 2016 classification is 82%.

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.

Colorectal cancer with invasive micropapillary components (IMPCs) shows high lymph node metastasis and a poor prognosis: A retrospective clinical study

OBJECTS

The present study aimed to identify the clinicopathological characteristics of colorectal cancer (CRC) with invasive micropapillary components (IMPCs) and the relationship between different amounts of micropapillary components and lymph node metastasis.

METHODS

A cohort of 363 patients with CRC who underwent surgical treatment in the Second Affiliated Hospital of Zhejiang University School of Medicine between January 2013 and December 2016 were retrospectively reviewed. We compared the clinicopathological characteristics, including survival outcomes and immunohistochemical profiles (EMA, MUC1, MLH1, MSH2, MSH6, and PMS2), between CRC with IMPCs and those with conventional adenocarcinoma (named non-IMPCs in this study). Logistic regression was used to identify the association between IMPCs and lymph node invasion. A multivariate analysis was performed using the Cox proportional hazard model to evaluate significant survival predictors.

RESULTS

Among 363 patients, 76 cases had IMPCs, including 22 cases with a lower proportion of IMPCs (≤5%, IMPCs-L) and 54 cases with a higher proportion (>5%, IMPCs-H). Compared to the non-IMPC group, the IMPC group (including both IMPC-L and IMPC-H) had a lower degree of tumor differentiation (P = .000), a higher N-classification (P = .000), more venous invasion (P = .019), more perineural invasion (P = .025) and a later tumor node metastasis (TNM) stage (P = .000). Only tumor differentiation (P = .031) and tumor size (P = .022) were different between IMPCs-L and IMPCs-H. EMA/MUC1 enhanced the characteristic inside-out staining pattern of IMPCs, whereas non-IMPCs showed luminal staining patterns. The percentage of mismatch repair deficiency (dMMR) in the non-IMPC group was much higher than that in the IMPC group (14.7% vs 4.7%). The overall survival time of patients with IMPCs was significantly less than that of patients with non-IMPCs (P = .002), then that of IMPCs-H was lower than that of IMPCs-L (P = .030). Logistic regression revealed that patients with IMPCs were associated with lymph metastasis, regardless of the proportion of IMPCs. Multivariate analysis demonstrated both IMPCs-L and IMPCs-H as negative prognostic factors.

CONCLUSIONS

IMPCs are significantly associated with lymph node metastasis and poor outcome, and even a minor component (≤5%) may render significant information and should therefore be part of the pathology report.

Genomic heterogeneity in bladder cancer: challenges and possible solutions to improve outcomes

Histological and molecular analyses of urothelial carcinoma often reveal intratumoural and intertumoural heterogeneity at the genomic, transcriptional and cellular levels. Despite the clonal initiation of the tumour, progression and metastasis often arise from subclones that can develop naturally or during therapy, resulting in molecular alterations with a heterogeneous distribution. Variant histologies in tumour tissues that have developed distinct morphological characteristics divergent from urothelial carcinoma are extreme examples of tumour heterogeneity. Ultimately, heterogeneity contributes to drug resistance and relapse after therapy, resulting in poor survival outcomes. Mutation profile differences between patients with muscle-invasive and metastatic urothelial cancer (interpatient heterogeneity) probably contribute to variability in response to chemotherapy and immunotherapy as first-line treatments. Heterogeneity can occur on multiple levels and averaging or normalizing these alterations is crucial for clinical trial and drug design to enable appropriate therapeutic targeting. Identification of the extent of heterogeneity might shape the choice of monotherapy or additional combination treatments to target different drivers and genetic events. Identification of the lethal tumour cell clones is required to improve survival of patients with urothelial carcinoma.

Micropapillary Cervical Adenocarcinoma: A Clinicopathologic Study of 44 Cases

Micropapillary adenocarcinoma has been reported as an aggressive variant of adenocarcinoma in several organs, where it is associated with poor clinical outcome. This study reports the clinicopathologic features and outcomes of cervical adenocarcinomas with a micropapillary component (micropapillary cervical adenocarcinomas); this represents the largest reported study of these neoplasms. The study comprised 44 cervical adenocarcinomas of usual (human papillomavirus-related)-type (84%), mucinous, not otherwise specified (4.5%), gastric-type (4.5%), endometrioid (4.5%), and adenosquamous carcinoma (2%). The micropapillary component comprised >50% of the neoplasm in 34 cases (77%) (group 1), and 10% to 50% in 10 cases (23%) (group 2). Lymph node metastasis was present in 41 of 44 (93%) cases and typically the nodal tumor retained a prominent micropapillary morphology. Follow-up ranged from 7 to 123 months (mean, 65.9 mo). Seventeen of 44 (38.6%) patients had no evidence of disease on follow-up, 6/44 (13.6%) were alive with disease, and 21/44 (47.7%) died of disease. There were no survival differences between group 1 and group 2. On univariate analysis, lymph node metastasis (P=0.0015), lymphovascular space invasion (P=0.002), parametrial involvement (P=0.03), and depth of stromal invasion (P=0.045) were related to tumor recurrence. On multivariate analysis, lymph node metastasis (P=0.001), and extent of lymphovascular space invasion (P=0.027) were significant independent predictors of tumor recurrence. Our study shows that a micropapillary component in cervical adenocarcinoma may be associated with aggressive behavior and that a micropapillary architecture may occur within a variety of types of cervical adenocarcinoma.

Glandular Tumors of the Urachus and Urinary Bladder: A Practical Overview of a Broad Differential Diagnosis

Primary glandular tumors of the urachus and urinary bladder are an intriguing group of clinically and morphologically diverse neoplasms for which there have been recent refinements in diagnostic subclassification and advances in molecular pathology. In addition, the urachus and urinary bladder may be secondarily involved by tumors with glandular differentiation that demonstrate remarkable morphologic, immunophenotypic, and molecular overlap. Thus, surgical pathologists need to be aware of the broad differential diagnosis of glandular tumors that involve the urachus and urinary bladder and have a practical diagnostic framework to evaluate these lesions in routine clinical practice. In this review, we summarize the salient clinical, morphologic, immunohistochemical, and molecular features of glandular tumors of the urachus and urinary bladder, including mucinous cystic tumors of the urachus, noncystic urachal adenocarcinomas, urothelial carcinomas with glandular or pseudoglandular features, primary urinary bladder adenocarcinomas, and Müllerian-type carcinomas, highlighting the strengths and limitations of various diagnostic features and ancillary tests, as well as the need for close clinical and radiographic correlation.

Micropapillary adenocarcinoma of lung: Morphological criteria and diagnostic reproducibility among pulmonary pathologists

CONTEXT

Invasive micropapillary adenocarcinoma (MPC) is an aggressive variant of lung adenocarcinoma, frequently manifesting with advanced stage lymph node metastasis and decreased survival.

OBJECTIVE

Identification of this morphology is important, as it is strongly correlated with poor prognosis regardless of the amount of MPC component. To date, no study has investigated the morphological criteria used to objectively diagnose it.

DESIGN

Herein, we selected 30 cases of potential MPC of lung, and distributed 2 digital images per case among 15 pulmonary pathology experts. Reviewers were requested to diagnostically interpret, assign the percentage of MPC component, and record the morphological features they identified. The noted features included: columnar cells, elongated slender cell nests, extensive stromal retraction, lumen formation with internal epithelial tufting, epithelial signet ring-like forms, intracytoplasmic vacuolization, multiple nests in the same alveolar space, back-to-back lacunar spaces, epithelial nest anastomosis, marked pleomorphism, peripherally oriented nuclei, randomly distributed nuclei, small/medium/large tumor nest size, fibrovascular cores, and spread through air-spaces (STAS).

RESULTS

Cluster analysis revealed three subgroups with the following diagnoses: "MPC", "combined papillary and MPC", and "others". The subgroups correlated with the reported median percentage of MPC. Intracytoplasmic vacuolization, epithelial nest anastomosis/confluence, multiple nests in the same alveolar space, and small/medium tumor nest size were the most common criteria identified in the cases diagnosed as MPC. Peripherally oriented nuclei and epithelial signet ring-like forms were frequently identified in both the "MPC" and "combined papillary and MPC" groups.

CONCLUSIONS

Our study provides objective diagnostic criteria to diagnose MPC of lung.

Histological variants in non-muscle invasive bladder cancer

Several studies evaluated the role of histological variants on oncological outcomes after radical cystectomy (RC) and they were found significantly associated with worse recurrence and survival. Sparse data exists regarding the role variant histology in non-muscle invasive diseases: assessing their relationship with recurrence and progression is important to understand the most effective treatment and follow-up schedule. For these reasons, the aim of the present non-systematic review was to assess the literature on variant histology in non-muscle invasive bladder cancer (BCa). The diagnosis of presence variant histology at transurethral resection (TUR) specimens challenging for pathologists and several studies published in literature evaluated concordance between TUR and RC specimen with discordant results. These differences are probably related to diversity in collection of samples and pathological evaluation and underline the necessity to have good tissue-sample and a pathologic evaluation performed by expert and dedicated uropathologists. Treatment of BCa with variant histology shall include immediate RC in case of plasmacitoid, pure squamous, micropapillary and sarcomatoid variants. The neuroendocrine differentiation, therefore, showed chemosensitiveness, and RC preceded by neoadjuvant chemotherapy should be proposed. Intravesical instillations with Bacillus Calmette Guerin (BCG) can be suggested in very selected cases of nested and glandular variants.

High-grade ovarian serous carcinomas: Significant correlation of histologic patterns with IMP3 and E-Cadherin predicting disease recurrence and survival

Most high-grade serous carcinomas (HGSC) of the ovary are advanced stage tumors with early recurrences. However, some tumors do not recur and have a better survival. We identified such cases of HGSC and compared those with the cases that recurred and assessed the relationship between patterns of invasion (intracystic, IC; micropapillary, MP; nonpapillary, NP) with IMP3 and E-Cadherin expression, and evaluated their predictive role in recurrence and survival. The study comprised of seventeen tumors recurred within 18 months of follow-up and 14 cases that did not recur with a minimum follow-up of 49 months. 73% tumors with predominantly MP pattern recurred, while only 27% of non-recurrent tumors showed this pattern. In contrast, predominant NP and IC patterns were seen in 71% of the non-recurrent and in 35% of recurrent tumors. 67.7% tumors expressed IMP3 and all cases expressed E-Cadherin. The tumors with a higher percentage of destructive invasion showed higher IMP3 positivity and greater chances of recurrence, whereas tumors with higher percentage of pushing invasion showed lower IMP3 positivity and lesser chances of recurrence (p = 0.02). IMP3-negative tumors had lower odds of recurrence than IMP3-positive ones (p = 0.01). The patients with negative IMP3 staining had a significantly higher OS than those with IMP3 positive tumors (p = 0.01), regardless of the histologic patterns. Also, reduction in E-Cadherin staining in the metastatic site led to poor DFS (p = 0.016) and OS (p = 0.006). IMP3 may serve as a useful prognostic marker that can stratify patients of advanced stage, high-grade serous carcinomas into two distinct subsets: majority with early recurrence with an infiltrative pattern of invasion and IMP3 positivity particularly in the MP areas; and a smaller subset that do not show early recurrence having pushing borders and are IMP3 negative. Also, E-Cadherin showed significant decrease in expression in the metastatic site of the recurrent cases.

Outcomes of nonmetastatic micropapillary variant upper tract urothelial carcinoma

PURPOSE

Micropapillary variant upper tract urothelial cancer (MP-UTUC) is a rare malignancy with little known regarding its clinical course and/or optimal treatment. In this case series, we describe patient characteristics, surgical treatment, oncologic outcomes, and response to perioperative chemotherapy.

MATERIALS AND METHODS

We conducted a review to identify patients with MP-UTUC treated at our center between January 1994 and October 2017. Clinicopathologic data was obtained. Descriptive statistics, Kaplan-Meier analysis, Cox proportional hazards, and nearest neighbor matching were used to examine the cohort.

RESULTS

Eighteen, (4.3%) of 416 patients were found to have MP-UTUC at our institution over a 23-year period. The majority of patients had ≥pT3 disease at the time of extirpative surgery (13/18, 72%) and one was identified as MP-UTUC prior to surgery. Seven patients received neoadjuvant chemotherapy and six patients received adjuvant chemotherapy. Median overall, cancer specific, and recurrence free survival were 3.29, 3.29, and 1.69 years, respectively for MP-UTUC. There was no survival difference between conventional UTUC and MP-UTUC when matched for age, stage, grade, lymphovascular invasion, and margins (HR 1.18, P = 0.567). No MP-UTUC patients receiving neoadjuvant and adjuvant chemotherapy had apparent pathologic down staging, and of those receiving adjuvant chemotherapy two-thirds died of disease within 2 years.

CONCLUSIONS

MP-UTUC is a rare, and in most cases aggressive malignancy that commonly presents as locally advanced disease. In this case series, MP-UTUC does not appear to respond to perioperative chemotherapy as neoadjuvant and adjuvant chemotherapy did not result in apparent pathologic down staging and the majority of those receiving adjuvant chemotherapy died from MP-UTUC.

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.

Study of Histopatological Parameters of Gastric Carcinomas with Micropapillary Component

Micropapillary carcinoma was recently identified as a carcinoma variant characterized by the presence of small clusters of tumor cells located in optically empty spaces. The study included a number of 14 cases represented by surgical excision specimens diagnosed with gastric carcinoma (tubular, papillary and signet-ring) which associated the micropapillary component in variable proportions. Regarding the low-grade tubular carcinomas, the micropapillary component represented less than 25% of the tumor, while in the high-grade tubular carcinomas and papillary carcinomas it represented 25-50%. Among signet-ring carcinomas, the micropapillary component had a percentage of over 50. The depth of invasion was frequently associated with T3 and T4 categories. Lymph nodes metastasis were found in ten cases and distant metastasis were present in three cases. Recognition of the micropapillary component associated with gastric carcinoma represents an aspect of great importance because it is frequently correlated with unfavorable prognosis parameters.

Cell Polarity Reversal Distinguishes True Micropapillary Growth From Retraction Artifact in Invasive Urothelial Carcinoma

Focal micropapillary features in invasive urothelial carcinoma is sometimes difficult to distinguish from retraction artifact morphologically. Cell polarity reversal has been demonstrated in micropapillary tumors by epithelial membrane antigen (EMA) immunostaining. We have previously described the use of E-cadherin as a cell polarity marker in ovarian micropapillary serous borderline tumors. The aim of this study was to evaluate the utility of immunohistochemistry for EMA and E-cadherin in differentiating micropapillary urothelial carcinoma from retraction artifact. We identified 29 invasive urothelial carcinomas with micropapillary features and 30 invasive urothelial carcinomas without reported micropapillary features but with areas of retraction artifact. Cell polarity reversal was considered present if E-cadherin showed membranous apical cup-like staining or if EMA demonstrated a well-defined basal staining towards the stroma. Twenty-seven of 29 cases (93%) of urothelial carcinoma with micropapillary features demonstrated EMA or E-cadherin staining patterns consistent with cell polarity reversal. Staining consistent with micropapillary architecture was identified with both markers in 20 of these 27 cases (74%). Six cases showed reversal of polarity by E-cadherin alone, whereas 1 case showed polarity reversal by EMA alone. Retraction artifacts showed circumferential staining by E-cadherin and lacked well-defined basal staining by EMA. Three cases originally classified as with retraction artifact showed reversal of cell polarity by both EMA and E-cadherin and were reclassified as micropapillary. Our data show that pathologists can reliably make this distinction in most cases. However, in some cases with ambiguous features, EMA and E-cadherin immunostaining may aid in resolving this diagnostic dilemma.

Updates on the Genetics and Molecular Subtypes of Urothelial Carcinoma and Select Variants

Urothelial carcinoma is a morphologically and genomically heterogeneous disease that exhibits a wide spectrum of morphologic features and molecular alterations and subtypes. Classic urothelial carcinoma (not otherwise specified) is the most common tumor type that develops in the urinary bladder but many, well-documented, variant histologies are commonly encountered in approximately one-third of invasive urothelial carcinoma, including squamous, glandular, micropapillary, sarcomatoid, small cell/neuroendocrine, clear cell, lymphoepithelioma-like, and plasmacytoid types, among others. In this review, we provide an update on the molecular advances in urothelial carcinoma and some of its variant histologies.

Invasive Micropapillary Carcinoma of the Uterine Cervix: Case Report of a Rare Entity

Invasive micropapillary carcinoma (IMPC) is a rare subtype of adenocarcinoma found in many organs. Only 1 case of IMPC of the uterine cervix has been reported. We report a rare case of IMPC in the uterine cervix. A 61-yr-old woman presented to our hospital for vaginal bleeding and abdominal pain. A papillary tumor was found in the uterine cervix. Cervical cytology revealed abnormal cells suggesting carcinoma in situ and adenocarcinoma. A follow up biopsy revealed adenocarcinoma. She underwent radical hysterectomy and bilateral adnexectomy. Histologically, carcinoma in situ and IMPC were found in the uterine cervix. Lymphatic infiltration was present in the cerix and in the right cardinal ligament. A pelvic lymph node metastasis was also identified. Clinical FIGO stage was IIb and pathologic stage was pT2bN1M0. Postoperative positron emission tomography-computed tomography revealed paraaortic lymph node metastasis. She is alive with disease 2 yr 9 mo after surgery. Positive p16 immunostaining and high-risk human papilloma virus in situ hybridization revealed human papilloma virus infection. Interleukin-17 was expressed in the tumor cells which might be related to the extensive neutrophilic infiltration and tumor progression. This is the first case report in which interleukin-17 expression is observed in the tumor cells of IMPC.

Urinary Bladder Pathology: World Health Organization Classification and American Joint Committee on Cancer Staging Update

Context.—

Since the publication of the previous World Health Organization (WHO) Classification of Tumours on the Pathology and Genetics of Tumours of the Urinary System and Male Genital Organs in 2004, significant new knowledge has been generated regarding the pathology and genetics of bladder neoplasia. Publication of the 2016 WHO “Blue Book” has codified that new data into updated recommendations for classification and prognostication. Similarly, the recent release of the 8th edition of the American Joint Committee on Cancer (AJCC) Cancer Staging Manual, which was implemented in January 2018, has also addressed staging criteria for bladder cancer in several unique settings to clarify their application.

Objective.—

To highlight subtle changes within the recent WHO and AJCC publications that may affect daily surgical pathology practice.

Data Sources.—

Peer-reviewed published literature, the 2016 WHO Classification of Tumours of the Urinary System and Male Genital Organs, and the 8th edition of the AJCC Cancer Staging Manual were reviewed.

Conclusions.—

Selected changes and/or clarifications are discussed and include classification of flat and papillary urothelial neoplasia, select variant patterns of invasive urothelial carcinoma, staging of invasive carcinoma in bladder diverticula, and staging of carcinomas involving the prostate gland.

Precise pathologic diagnosis and individualized treatment improve the outcomes of invasive micropapillary carcinoma of the breast: a 12-year prospective clinical study

Invasive micropapillary carcinoma of the breast is a histologic subtype of breast cancer and associated with high incidence of lymphovascular invasion, lymph node metastasis and poor prognosis. The aim of this prospective study was to investigate the impact of precise pathologic diagnosis and individualized treatment on the outcomes of invasive micropapillary carcinoma of the breast. The study group included 2299 women with invasive micropapillary carcinoma diagnosed at Tianjin Medical University Cancer Institute and Hospital between January 2004 and December 2015. In the study group, specimens were examined with the method of whole-specimen orientation and serial sectioning, and patients received precise pathological diagnosis and individualized treatment. The control group of invasive micropapillary carcinoma consisted of 163 cases, identified through a retrospectively review of 9056 invasive carcinomas diagnosed at our institution between January 1989 and December 2003 using the standard pathology-evaluation method (i.e., not using the whole-specimen orientation and serial-sectioning method). The clinicopathological features, treatments and outcomes were compared between the two groups. The incidence of invasive micropapillary carcinoma in the study group was 6% (2299/39,714 cases), significantly higher than that of the control group (2%; 163/9056 cases). The 5-year disease-free survival in the study group was significantly higher than that in the control group (83.8 vs.45.4%; p < 0.05). The 5-year overall survival was significantly increased from 57.4% in the control group to 90.9% in the study group (p < 0.05). In the multivariate analysis, lymphovascular invasion, estrogen receptor status and lymph node metastasis were independent prognostic factors. Although invasive micropapillary carcinoma of the breast is associated with poor prognosis, precise pathologic diagnosis and individualized treatment improved the disease-free survival and overall survival of invasive micropapillary carcinoma patients. Precise pathological diagnosis is the premises for individualized treatments and for improving the outcomes of patients with invasive micropapillary carcinoma of the breast.

The clinicopathological significance of micropapillary pattern in colorectal cancers

The aim of the present study is to elucidate the clinicopathological significance and prognostic role of micropapillary pattern (MPP) in colorectal cancer (CRC). We investigated the correlation between the presence of MPP and clinicopathological characteristics and prognosis in 266 CRCs. In addition, the clinicopathological significance of MPP in mucin pools was investigated and compared to pure MPP, which is not associated with mucin pools. MPP, regardless of its proportion in the overall tumor, was found in 74 of 266 CRCs (27.8%). The rate of MPP in proportions ≥5% was 9.4% (25 of 266 cases). CRC with MPP showed higher rates of vascular and lymphatic invasion, higher metastatic lymph node ratio, and higher pT stage compared to CRC without MPP. In addition, increasing proportion of MPP in overall tumor showed more frequent vascular and lymphatic invasions (P = .002 and P = .008, respectively). Among 74 CRCs with MPP, 25 CRCs were found in mucin pools (33.8%). These cases were more right-sided and poorly differentiated with less frequent lymphatic invasion and lymph node metastasis, compared to CRCs with pure MPP. The presence of MPP significantly correlated with worse overall survival (P = .010). In 74 CRCs with MPP, overall survival significantly differed between pure MPP and MPP in mucin pools (P = .003). Taken together, our data suggest that the presence of MPP significantly correlated with aggressive tumor behavior and worse survival in CRC. In addition, the clinicopathological significance of MPP in mucin pools differed from CRC with pure MPP.

Intratumoral heterogeneity of ERBB2 amplification and HER2 expression in micropapillary urothelial carcinoma

Micropapillary urothelial carcinoma (MPUC) is a rare but an aggressive variant of urothelial carcinoma. MPUC has been shown to commonly exhibit ERBB2 amplification and HER2 protein overexpression, but the frequency and distribution of these findings within micropapillary (MP) and not otherwise specified (NOS) components of tumors with mixed histology have not been addressed. Therefore, we evaluated ERBB2 amplification and HER2 expression in 43 MPUC cases by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC). Of the 35 tumors containing both MP and NOS components, ERBB2 amplification was present in both the MP and NOS components of 12 tumors (34.3%), in only the MP component of 11 tumors (31.4%), and exclusively in the NOS component of 4 tumors (11.4%). HER2 protein overexpression was significantly more commonly present in the MP component compared to the NOS component within the same tumor (68.6% versus 34.3%, P = .012). Overall, there was a moderately positive correlation between HER2 protein expression and ERBB2 amplification in both MP (ρ = 0.59, P < .001) and NOS (ρ = 0.70, P < .001) components. All MP/NOS areas with IHC score 3+ and none of MP/NOS areas with IHC score 0 were associated with ERBB2 amplification. We conclude that ERBB2 amplification and HER2 overexpression are preferentially but not exclusively identified in the MP component compared to the NOS component within the same tumor. Our findings identify the presence of intratumoral heterogeneity of ERBB2 amplification and HER2 expression in MPUC and provide grounds for further investigation into the mechanisms underlying the development of MPUC.

Invasive micropapillary carcinoma component is an independent prognosticator of poorer survival in Stage III colorectal cancer patients

Background

Invasive micropapillary carcinoma (IMPC) is an aggressive variant of adenocarcinoma found in several organs. Recent studies showed that IMPC in colorectal cancer leads to poorer prognosis than conventional colorectal cancer; however, the influence of IMPC on outcomes remains unclear. The present study aimed to identify the clinicopathological characteristics of colorectal cancers with IMPCs, and to evaluate the prognostic significance of IMPCs per se.

Methods

We retrospectively analyzed data from 837 patients with colorectal cancer who underwent surgical treatment. We compared the clinicopathological characteristics and survival outcomes of colorectal cancer patients with IMPCs to those without.

Results

Among 837 patients, 130 (16%) had an IMPC component, including 0 (0%) of 18, 9 (4.2%) of 215, 34 (13%) of 254, 59 (24%) of 249 and 28 (27%) of 101 patients with TNM Stages 0, I, II, III and IV, respectively. The 3-year disease-free survival (DFS) rates were significantly worse for Stage III patients with IMPC than for those without (55.3% vs. 78.7% respectively, P < 0.001), but not in patients with other stages. Multivariate analyses of patients with Stage III colorectal cancer found IMPC to be associated with significantly worse DFS (P = 0.026), as were high CEA levels, tumor budding and TNM staging. IMPC was only significantly associated with tumor invasion (P = 0.045) and venous invasion (P = 0.045) in Stage III tumors.

Conclusions

Identifying IMPC components in Stage III colorectal cancer is crucial, as their presence is significantly associated with poorer survival.

The Hobnail Variant of Papillary Thyroid Carcinoma: Clinical/Molecular Characteristics of a Large Monocentric Series and Comparison with Conventional Histotypes

BACKGROUND

The hobnail variant of papillary thyroid carcinoma (HPTC) has an aggressive behavior. The aims of this prospective study were to define the clinical/molecular characteristics of HPTC, and to compare them to those of conventional papillary thyroid carcinoma (PTC).

METHODS

From 2010 to 2016, 25 cases of HPTC, characterized clinically and molecularly (BRAF, RAS, TERT promoter, and TP53 mutations), were compared to a series of 165 consecutive cases of PTC. All patients underwent total thyroidectomy and received radioactive iodine treatment. Follow-up was available for 19 HPTC patients.

RESULTS

Among the HPTC patients, 64% had a hobnail component ≥30%, and 64% had multifocal disease. The mean tumor size was 30 mm; 96% of tumors were angio-invasive; 68% were N1, and 12% were M1; 58% harbored the BRAF^V600E mutation, 12% had a mutation in the TERT promoter, 17% had a TP53 mutation, and not had a RAS mutation. At a mean follow-up of 39 months, 32% of patients had biochemical and/or structural disease. Tumor size was the only significant difference between patients with persistent disease and those with an excellent response (40 mm and 24 mm, respectively; p = 0.02). Compared to the PTC control group, the HPTC patients had larger tumors (30 mm vs. 16 mm; p < 0.001), more frequent lymph node involvement (68% vs. 38%; p = 0.01), and remote disease (16% vs. 3%; p < 0.0001), a similar prevalence of the BRAF^V600E mutation (58% vs. 59%), a higher prevalence of TP53 mutations (17% vs. 1%; p < 0.05), and a worse outcome (structural/biochemical disease: 32% vs. 9%; p < 0.0001).

CONCLUSIONS

HPTC is an aggressive variant, characterized by large tumor size, lymph node involvement, a tendency to metastasize, and a worse outcome.

Cervical carcinomas with a micropapillary component: a clinicopathological study of eight cases

AIMS

Micropapillary carcinomas, or carcinomas with a micropapillary component, are well recognised in the breast and other anatomical sites. However, they have seldom been described in the cervix. In this article, we present a clinicopathological analysis of eight cervical tumours that showed at least a focal (≥5%) component of micropapillary carcinoma.

METHODS AND RESULTS

The study group comprised eight cervical carcinomas (four adenocarcinomas and four adenosquamous carcinomas) with a micropapillary component. The median patient age was 41.5 years (range 27-65 years). At presentation, five patients were stage IB, two were stage IIB, and one was stage IV. The micropapillary component accounted for ≤25% of the tumour on initial biopsy or resection specimens in all but one case. Immunohistochemistry showed 'inside-out' (reverse polarity) mucin 1 staining along the cell membrane abutting the stroma. Four patients developed metastasis, all of whom showed a pure micropapillary pattern; this led to a misdiagnosis of an apparently independent peritoneal serous carcinoma in one case. All tumours showed diffuse p16 expression, and all three cases that were tested were positive for human papillomavirus (HPV) 18. Three of the six patients with at least 12 months of follow-up died of disease, and one is alive with distant metastasis.

CONCLUSIONS

Usual-type (HPV-related) cervical carcinomas may show micropapillary differentiation, usually as a focal finding, and the cells show reverse polarity like similar tumours arising in other sites. Micropapillary cervical carcinoma appears to be a clinically aggressive malignancy, although this needs to be confirmed in larger studies.

Overexpression of β1 integrin contributes to polarity reversal and a poor prognosis of breast invasive micropapillary carcinoma

Invasive micropapillary carcinoma (IMPC) of the breast is a highly aggressive breast cancer. Polarity reversal exemplified by cluster growth is hypothesized to contribute to the invasiveness and metastasis of IMPC. In this study, we demonstrate that levels of β1 integrin and Rac1 expression were greater in breast IMPC than in invasive breast carcinoma of no specific type and paraneoplastic benign breast tissue. We show that silencing β1 integrin expression using the β1 integrin inhibitor AIIB2 partially restored polarity in IMPC primary cell clusters and downregulated Rac1. Thus, overexpression of β1 integrin upregulates Rac1. Univariate analysis showed that overexpression of β1 integrin and Rac1 was associated with breast cancer cell polarity reversal, lymph node metastasis, and poor disease-free survival in IMPC patients. Multivariate analysis revealed that polarity reversal was an independent predictor of poor disease-free survival. These findings indicate that overexpression of β1 integrin and the resultant upregulation of Rac1 contribute to polarity reversal and metastasis of breast IMPC, and that β1 integrin and Rac1 could be potential prognostic biomarkers and targets for treatment of breast IMPC.

Serous Carcinoma Mimicking Primary Urothelial Carcinoma on Clinical Evaluation and Pathology: A Potential Diagnostic Pitfall

Context.—

Serous carcinoma of the gynecologic tract often involves the external bladder wall and can occasionally mimic primary urothelial carcinoma of the bladder.

Objective.—

To define the spectrum of morphologic and immunohistochemical features that characterize serous carcinoma involving the bladder wall and its distinction from urothelial carcinoma.

Design.—

We reviewed all cases of serous carcinoma secondarily involving the bladder wall from the University of California San Diego and Polytechnic Institute for histopathologic and immunohistochemical features.

Results.—

We identified 20 cases of Müllerian high-grade serous carcinoma involving the bladder wall. Five cases were clinical mimics of urothelial carcinoma, including 2 cases that presented as a large, transmural, primary bladder mass without precedent gynecologic history in women younger than 60 years, and 3 cases presumed to be new bladder carcinoma occurring distant to a serous carcinoma diagnosis. A subset of cases were morphologic mimics of urothelial carcinoma, which showed nested growth patterns (2 of 20; 10%), squamouslike foci (2 of 20; 10%), spindled/sarcomatoid growth (2 of 20; 10%), basaloid morphology (3 of 20; 15%), and syncytial growth patterns (1 of 20; 5%). Immunohistochemical stains in 17 cases showed immunoreactivity for CK7 (17 of 17; 100%), WT1 (17 of 17; 100%), uroplakin (UP) II (1 of 17; 6%), p63 (2 of 17; 12%), GATA3 (2 of 17; 12%), and PAX8 (17 of 17; 100%).

Conclusions.—

A subset of serous carcinomas involving the bladder wall can mimic urothelial carcinoma. Awareness of this mimicker and use of an immunohistochemical panel that includes CK7, WT1, UPII, PAX8, p63, and GATA3 can be helpful in confirming the diagnosis.

Phosphorylated mTOR Expression Profiles in Human Normal and Carcinoma Tissues

Mammalian target of rapamycin (mTOR) is a key controller of cell growth and proliferation in normal tissues and solid tumors. In the present study, an immunohistochemical analysis of the expression pattern of phosphorylated mTOR (p-mTOR) was performed in human normal fetal and adult tissues and various carcinoma tissues. p-mTOR expression showed tissue and cell type specificity in normal and cancer tissues. In normal fetal and adult tissues, p-mTOR staining was observed in the intestinal crypt, intrahepatic bile ductule, pancreatic duct, distal nephron of the kidney, umbrella cell of urothelium, mesothelial cell, and choroid plexus. In cancer tissues, p-mTOR expression was higher in adenocarcinoma than in other types of cancers, in metastatic cancer than in primary cancer, and in the forefront of the infiltrating cancer cells. These results suggest that p-mTOR is implicated not only in cell proliferation but also in tubular morphogenesis in normal and cancer tissues. In addition, mTOR activation appears to be associated with cancer cell invasion and migration in solid tumors.

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.

Invasive Micropapillary Carcinoma of the Breast: An Update

CONTEXT

-Invasive micropapillary carcinoma (IMPC) is a distinct variant of mammary carcinoma in which tumor cells are arranged in morulelike clusters devoid of fibrovascular cores and situated within empty stromal spaces. Identification of IMPC can be achieved by the assessment of morphologic features in conjunction with the characteristic "inside-out" staining pattern of epithelial membrane antigen and sialyl Lewis X highlighted by immunohistochemical analysis. Although recognizing micropapillary architecture is often not challenging, the criteria for distinguishing between mixed and pure IMPC remain imprecise. Some mucin-producing carcinomas can also have micropapillary histology, but there is no consensus on whether these tumors are variants of IMPC or mucinous carcinomas. The molecular genetic studies demonstrate that IMPCs have distinct molecular genetic profiles, supporting the theory that they constitute distinct pathologic entities. However, genomic analyses have not identified any specific genomic aberration that may explain the distinctive morphology and clinical behavior of IMPC.

OBJECTIVE

-To provide an overview on the current concepts in the diagnosis and pathogenesis of IMPC of the breast, incorporating recent molecular genetic advances and prognosis-based reclassification.

DATA SOURCES

-PubMed search and the cited references were reviewed.

CONCLUSIONS

-The recent evolution of prognosis-based reclassification and molecular genetic advances has enhanced our knowledge of the pathogenesis of IMPC of the breast. Additional studies might reveal consistent molecular alterations that underlie the formation of the inside-out growth pattern, and they might elucidate the molecular mechanisms responsible for the unfavorable clinical behavior of IMPC.

The micropapillary/hobnail variant of papillary thyroid carcinoma: A review of series described in the literature compared to a series from one southern Italy pathology institution

Papillary thyroid carcinoma (PTC) has a good prognosis with a 10-yr survival greater than 90%. Recently, a micro-papillary pattern with hobnail appearance (MPHC) in PTC has been indicated as associated with poor prognosis, but this suggestion is based only on a few cases from geographical areas different from ours. Two-hundred ninety-nine consecutive PTC cases were collected between the years of 1992 and 2014 at our institution. The corresponding histologic sections (at least 6 for each case) were stained with hematoxylin and eosin and reviewed independently by two pathologists to reach a consensus on the identification and quantification of the MPHC. As done in other cohorts, parallel serial sections were stained with antisera for thyroglobulin, epithelial membrane antigen, thyroid-transcription-factor-1 and Ki 67. BRAF gene mutation at codon 600 and RET/PTC1 gene rearrangements were searched. A comparative statistical analysis was done between the present series and previously published series. Of the 295 PTC, 124 (42.5%) were follicular, 104 (35%) classic, 34 (11.5%) sclerosing, 15 (5%) tall cells, 10 (3.4%) Warthin-like, and 8 (2.7%) MPHC. Four MHPC cases (50%) harbored the BRAF V600E variant, while one was positive for RET/PTC1 rearrangement. Our rate of MPHC-PTC (2.7%) is 2X to 8X greater than those reported previously for cohorts from North America + North Italy, Korea and Mexico. MPHC prognosis appears to be better compared to other cohorts, probably due to not only to the lower rate of the vascular invasion, but also to the smaller size of the MPHC-PTC nodule.

Clinical risk stratification in patients with surgically resectable micropapillary bladder cancer

OBJECTIVE

To analyse survival in patients with clinically localised, surgically resectable micropapillary bladder cancer (MPBC) undergoing radical cystectomy (RC) with and without neoadjuvant chemotherapy (NAC) and develop risk strata based on outcome data.

PATIENTS AND METHODS

A review of our database identified 103 patients with surgically resectable (≤cT4acN0 cM0) MPBC who underwent RC. Survival estimates were calculated using Kaplan-Meier method and compared using log-rank tests. Classification and regression tree (CART) analysis was performed to identify risk groups for survival.

RESULTS

For the entire cohort, estimated 5-year overall survival and disease-specific survival (DSS) rates were 52% and 58%, respectively. CART analysis identified three risk subgroups: low-risk: cT1, no hydronephrosis; high-risk: ≥cT2, no hydronephrosis; and highest-risk: cTany with tumour-associated hydronephrosis. The 5-year DSS for the low-, high-, and highest-risk groups were 92%, 51%, and 17%, respectively (P < 0.001). Patients down-staged at RC <pT1 regardless of the use of NAC had the best survival (5-year DSS of 96% vs 45% for those not down-staged; P < 0.001), while those who were not down-staged despite NAC had 5-year DSS of only 17%.

CONCLUSION

In patients with surgically resectable MPBC, NAC appears to confer benefit to patients with muscle-invasive disease without hydronephrosis, while patients with cT1 disease can proceed to upfront RC. Patients with hydronephrosis do not appear to respond well to NAC and have poor prognosis regardless of treatment paradigm. However, further external validation studies are needed to support the proposed risk stratification before treatment recommendations can be made.