Lymphoepithelioma-like hepatocellular carcinoma: an uncommon variant of hepatocellular carcinoma with favorable outcome. Am J Surg Pathol. 2015;39:304-312. [PMID: 25675010 DOI: 10.1097/pas.0000000000000376]

Characterization of lymphocyte-rich hepatocellular carcinoma and the prognostic role of tertiary lymphoid structures

BACKGROUND & AIMS

Lymphocyte-rich hepatocellular carcinoma (LR-HCC) is largely unknown and a rare subtype of HCC with immune-rich stroma. Tertiary lymphoid structures (TLS), frequently observed in LR-HCC, are known to be prognostically significant in various malignancies; however, their significance in HCC remains unevaluated.

METHODS

Clinicopathologic data of 191 cases of surgically resected conventional HCC (C-HCC, n = 160) and LR-HCC (n = 31) were retrieved. Immunohistochemistry, multiplex immunofluorescence staining, RNA sequencing and proteomic analysis were conducted. Differences between the subtypes were statistically evaluated.

RESULTS

LR-HCC was significantly correlated to larger tumour size, higher Edmondson-Steiner grade, presence of TLS and higher CD3-, CD8- and FOXP3-positive T cell, high PD-1 and PD-L1 expression (p < .001 for all) compared to C-HCC. Patients with LR-HCC exhibited significantly better overall survival (OS) (p = .044) and recurrence-free survival (RFS) (p = .025) than C-HCC. LR-HCC demonstrated TLS signatures with significantly higher proteomic-based immune scores in 14 of 17 types of tumour-infiltrating immune cells. Furthermore, C-HCC with secondary follicles, the most mature form of TLS, exhibited significantly better OS (p = .031) and RFS (p = .033) than those without. Across the global proteome, LR-HCC was well-differentiated from C-HCC and a map of protein-protein interactions between tumour-infiltrating lymphocytes and HCC in tumour microenvironment was completed.

CONCLUSION

LR-HCC is clinicopathologically and molecularly distinct and shows better prognosis compared to C-HCC. Also, the presence of secondary follicle can be an important prognostic marker for better prognosis in both LR-HCC and C-HCC.

Unleashing the potential of gene signatures as prognostic and predictive tools: A step closer to personalized medicine in hepatocellular carcinoma (HCC)

Hepatocellular carcinoma (HCC) is one of the growing malignancies globally, affecting a myriad of people and causing numerous cancer-related deaths. Despite therapeutic improvements in treatment strategies over the past decades, HCC still remains one of the leading causes of person-years of life lost. Numerous studies have been conducted to assess the characteristics of HCC with the aim of predicting its prognosis and responsiveness to treatment. However, the identified biomarkers have shown limited sensitivity, and the translation of these findings into clinical practice has faced challenges. The development of sequencing techniques has facilitated the exploration of a wide range of genes, leading to the emergence of gene signatures. Although several studies assessed differentially expressed genes in normal and HCC tissues to find the unique gene signature with prognostic value, to date, no study has reviewed the task, and to the best of our knowledge, this review represents the first comprehensive analysis of relevant studies in HCC. Most gene signatures focused on immune-related genes, while others investigated genes related to metabolism, autophagy, and apoptosis. Even though no identical gene signatures were found, NDRG1, SPP1, BIRC5, and NR0B1 were the most extensively studied genes with prognostic value. Finally, despite challenges such as the lack of consistent patterns in gene signatures, we believe that comprehensive analysis of pertinent gene signatures will bring us a step closer to personalized medicine in HCC, where treatment strategies can be tailored to individual patients based on their unique molecular profiles.

Application of adoptive cell therapy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) remains a global health challenge. Novel treatment modalities are urgently needed to extend the overall survival of patients. The liver plays an immunomodulatory function due to its unique physiological structural characteristics. Therefore, following surgical resection and radiotherapy, immunotherapy regimens have shown great potential in the treatment of hepatocellular carcinoma. Adoptive cell immunotherapy is rapidly developing in the treatment of hepatocellular carcinoma. In this review, we summarize the latest research on adoptive immunotherapy for hepatocellular carcinoma. The focus is on chimeric antigen receptor (CAR)-T cells and T cell receptor (TCR) engineered T cells. Then tumour-infiltrating lymphocytes (TILs), natural killer (NK) cells, cytokine-induced killer (CIK) cells, and macrophages are briefly discussed. The main overview of the application and challenges of adoptive immunotherapy in hepatocellular carcinoma. It aims to provide the reader with a comprehensive understanding of the current status of HCC adoptive immunotherapy and offers some strategies. We hope to provide new ideas for the clinical treatment of hepatocellular carcinoma.

Clinicopathological characteristics and molecular analysis of lymphocyte-rich hepatocellular carcinoma

Lymphocyte-rich hepatocellular carcinoma (LR-HCC), a newly proposed subtype of HCC, is characterized with abundant lymphocyte infiltration in the tumor. LR-HCC has a relatively good prognosis and is quite rare (<1% of all HCC). We examined LR-HCC clinicopathological and molecular characteristics by analyzing 451 surgically resected HCC cases without any prior treatment history at our hospital between 2012 and 2021. Clinicopathological features of LR-HCC and other HCCs (non-LR-HCC) were compared. Neoplastic and nonneoplastic hepatocytes from LR-HCC (n = 4) were collected with a laser microdissection system; RNA was extracted, followed by microarray analysis to examine lymphocytic infiltration-related molecular targets. Immunohistochemical staining of identified molecular target was performed in LR-HCC and non-LR-HCC. CD3, CD20, and CD8 immunostaining was also performed in LR-HCCs. There were 28 cases of LR-HCC (6%). No statistically significant differences were found in clinicopathological features, except for gross type, between LR-HCC and non-LR-HCC cases. The LR-HCC 5-year survival rate was >90%. Microarray analysis revealed high CCL20 expression in LR-HCC cases; immunohistochemical study showed significantly higher CCL20 expression in LR-HCC (P < 0.01) than in non-LR-HCC. CCR6, the only CCL20 receptor, was observed in infiltrating lymphocytes and HCC cells in LR-HCC. There were significantly more CD3-positive cells than CD20-positive cells (P < 0.0001) in tumor-infiltrating lymphocytes, most of which were CD8-positive T cells. In conclusion, there were no significant differences in clinicopathological characteristics between LR-HCC and non-LR-HCC, except for gross and LR microscopic features. CCL20 expression in LR-HCC may contribute to infiltration of large numbers of CD8-positive lymphocytes.

Frequent expression of PD-L1 in lymphocyte-rich hepatocellular carcinoma: A report of 4 cases

BACKGROUND

Programmed death ligand 1 (PD-L1) is an immune checkpoint inhibitor. PD-L1 binds to its receptor programmed death receptor (PD-1) expressed by immune cells and plays a key role in regulating immune responses. Engagement of PD-L1 on cancer cells and PD-1 on immune cells avoid destruction of tumour cells by immune cells. Immunostaining with PD-L1 has been suggested as a biomarker predictive of antiPD-L1 immunotherapy. Lymphocyte-rich hepatocellular carcinoma (LrHCC) is a rare histological HCC subtype which is characterised by neoplastic epithelial cells intermixed with numerous immune cells.

METHODS

Here in we investigated immunohistochemical PD-L1 expression in 4 cases of LrHCC. Tumour proportion score (TPS) and immune cell score was recorded. Immunophenotypic characterization of the tumour and inflammatory cells was also done. Epstein-Barr encoding region (EBER) in situ hybridization (ISH) assay as performed in all four tumours.

RESULTS

Expression of PD-L1 was demonstrated in tumour epithelial cells and immune cells in all four cases. Incomplete to membranous staining was demonstrated in the tumour cells. Tumour proportion score (TPS) was 1.2-20 %. Immune cells demonstrated membranous and cytoplasmic immunostaining. Immune cell score was ≥1 % to >10 %.

CONCLUSION

PD-L1 expression in both tumour and immune cells suggests distinct immunogenic feature and potential role of antiPD-L1 therapies in cases with inoperable disease.

Advances in Histological and Molecular Classification of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a primary liver cancer characterized by hepatocellular differentiation. HCC is molecularly heterogeneous with a wide spectrum of histopathology. The prognosis of patients with HCC is generally poor, especially in those with advanced stages. HCC remains a diagnostic challenge for pathologists because of its morphological and phenotypic diversity. However, recent advances have enhanced our understanding of the molecular genetics and histological subtypes of HCC. Accurate diagnosis of HCC is important for patient management and prognosis. This review provides an update on HCC pathology, focusing on molecular genetics, histological subtypes, and diagnostic approaches.

Prognostic value of LI-RADS category on MRI in patients with primary hepatic lymphoepithelioma-like carcinoma

OBJECTIVES

To compare the clinical and MRI features of primary hepatic lymphoepithelioma-like carcinoma (LELC) categorized as LR-M or LR-4/5 using the Liver Imaging Reporting and Data System (LI-RADS) version 2018 and to determine the prognostic factors for recurrence-free survival (RFS).

METHODS

In this retrospective study, 37 patients with surgically confirmed LELC were included. Two independent observers evaluated preoperative MRI features according to the LI-RADS version 2018. Clinical and imaging features were compared between two groups. RFS and the associated factors were evaluated using Cox proportional hazards regression analysis, Kaplan-Meier analysis, and log-rank test.

RESULTS

In total, 37 patients (mean age, 58.5 ± 10.3 years) were evaluated. Sixteen (43.2%) LELCs were categorized as LR-M and twenty-one (56.8%) LELCs were categorized as LR-4/5. In the multivariate analysis, the LR-M category was an independent factor for RFS (HR 7.908, 95% CI 1.170-53.437; p = 0.033). RFS rates were significantly lower in patients with LR-M LELCs than in patients with LR-4/5 LELCs (5-year RFS rate, 43.8% vs.85.7%; p = 0.002).

CONCLUSION

The LI-RADS category was significantly associated with postsurgical prognosis of LELC, with tumor categorized as LR-M having a worse RFS than those categorized as LR-4/5.

KEY POINTS

• Lymphoepithelioma-like carcinoma patients categorized as LR-M have worse recurrence-free survival than those categorized as LR-4/5. • MRI-based LI-RADS categorization was an independent factor for postoperative prognosis of primary hepatic lymphoepithelioma-like carcinoma.

Refining Liver Biopsy in Hepatocellular Carcinoma: An In-Depth Exploration of Shifting Diagnostic and Therapeutic Applications

The field of hepatocellular carcinoma (HCC) has faced significant change on multiple levels in the past few years. The increasing emphasis on the various HCC phenotypes and the emergence of novel, specific therapies have slowly paved the way for a personalized approach to primary liver cancer. In this light, the role of percutaneous liver biopsy of focal lesions has shifted from a purely confirmatory method to a technique capable of providing an in-depth characterization of any nodule. Cancer subtype, gene expression, the mutational profile, and tissue biomarkers might soon become widely available through biopsy. However, indications, expectations, and techniques might suffer changes as the aim of the biopsy evolves from providing minimal proof of the disease to high-quality specimens for extensive analysis. Consequently, a revamped position of tissue biopsy is expected in HCC, following the reign of non-invasive imaging-only diagnosis. Moreover, given the advances in techniques that have recently reached the spotlight, such as liquid biopsy, concomitant use of all the available methods might gather just enough data to improve therapy selection and, ultimately, outcomes. The current review aims to discuss the changing role of liver biopsy and provide an evidence-based rationale for its use in the era of precision medicine in HCC.

Lymphocyte-Rich Hepatocellular Carcinoma with Multiple Lymphadenopathy and Positive Epstein-Barr Virus Encoding Region

Lymphocyte-rich hepatocellular carcinoma (HCC) represents the rarest subtype among the various subgroups of HCC, and limited clinical data are available for this particular subtype. It is commonly observed as a solitary lesion and tends to present at an early stage. Histopathological examination typically reveals tumor cells infiltrated by a lymphocyte-rich background, leading to its designation as lymphoepithelioma-like HCC. Unlike other lymphoepithelioma-like tumors associated with the Epstein-Barr virus (EBV), lymphocyte-rich HCC is predominantly negative for EBV. This subtype is characterized by more favorable clinical outcomes and prognosis compared to conventional HCC. Here, we present a case of lymphocyte-rich hepatocellular carcinoma (HCC) characterized by the presence of bilateral hepatic tumors and concurrent multiple lymphadenopathy. Interestingly, contrary to previous literature, the examination for the Epstein-Barr virus (EBV) revealed a positive result in this particular case.

Single-center experience in the diagnosis and treatment of lymphoepithelioma-like hepatic carcinoma

PURPOSE

Lymphoepithelioma-like hepatic carcinoma (LELC) is a rare malignant liver tumor and its preoperative diagnosis is challenging. The aim of this study was to optimize the diagnosis and treatment of LELC in a single large center.

METHODS

We conducted this retrospective analysis of 16 patients diagnosed with LELC in the First Affiliated Hospital of Zhejiang University between 2010 and 2022. Thirty-two cases of cholangiocarcinoma (ICC) and 48 cases of hepatocellular carcinoma (HCC) served as controls.

RESULTS

Most of the 16 patients with LELC included in this study had no specific symptoms. Histologically, 9 patients had lymphoepithelioma-like hepatocellular carcinoma (LEL-HCC), 5 had lymphoepithelioma-like cholangiocarcinoma (LEL-ICC) and 2 had LEL-HCC-ICC. LEL-HCC was usually accompanied by hepatitis B virus infection, while LEL-ICC was often accompanied by Epstein Barr virus (EBV) infection. During the follow-up period, no complication and deaths were observed and only one patient experienced recurrence. These results were obviously better than those in patients with HCC and ICC.

CONCLUSION

LELC is a rare malignant hepatic tumor. There are no specific symptoms or imaging modalities for accurate preoperative diagnosis of LELC. The diagnosis can be confirmed by pathology; however, the prognosis of LELC after resection is promising.

Understanding the Immunoenvironment of Primary Liver Cancer: A Histopathology Perspective

One of the most common cancers worldwide, primary liver cancer remains a major cause of cancer-related mortality. Hepatocellular carcinoma and cholangiocarcinoma represent the majority of primary liver cancer cases. Despite advances in the development of novel anti-cancer therapies that exploit targets within the immune system, survival rates from liver cancer remain poor. Furthermore, responses to immunotherapies, such as immune checkpoint inhibitors, have revealed limited and variable responses amongst patients with hepatocellular carcinoma, although combination immunotherapies have shown recent breakthroughs in clinical trials. This has shifted the focus towards improving our understanding of the underlying immune and molecular characteristics of liver tumours that may influence their response to immune-modulating treatments. In this review, we outline the complex interactions that occur in the tumour microenvironment of hepatocellular carcinoma and cholangiocarcinoma, respectively, from a histopathological perspective. We explore the potential role of a classification system based on immune-specific characteristics within each cancer type, the importance of understanding inter- and intra-tumoural heterogeneity and consider the future role of histopathology and novel technologies within this field.

Analysis of the Heterogeneity of the Tumor Microenvironment and the Prognosis and Immunotherapy Response of Different Immune Subtypes in Hepatocellular Carcinoma

Purpose

The current clinical classification of hepatocellular carcinoma (HCC) cannot well predict the patient's possible response to the treatment plan, nor can it predict the patient's prognosis. We use the gene expression patterns of patients with hepatocellular carcinoma to reveal the heterogeneity of hepatocellular carcinoma and analyze the differences in prognosis and immunotherapy response of different immune subtypes.

Methods

Firstly, using the hepatocellular carcinoma expression profile data of TCGA, combined with the single sample gene set enrichment analysis (ssGSEA) algorithm, the immune enrichment of the patient's tumor microenvironment was analyzed. Subsequently, the spectral clustering algorithm was used to extract different classifications, and the cohort of hepatocellular carcinoma was divided into 3 subtypes, and the correlation between immune subtypes and clinical characteristics and survival prognosis was established. The patient's risk index is obtained through the prognostic prediction model, suggesting the correlation between the risk index and various types of immune cells.

Results

We can divide the liver cancer cohort into three subtypes: stromal cell activated immune-enriched type (A-IS), general immune-enriched type (N-IS), and non-immune-enriched type (non-IS). The 3-year survival rate of TCGA's A-IS is higher than that of N-IS and non-IS, and the three components are significantly different (p = 0.017). The 3-year survival rates of ICGC's A-IS and N-IS groups were higher than those of the non-IS group. The analysis of the correlation between the risk index and immune cells showed that the patient's disease risk was significantly positively correlated with cancer-associated fibroblast (CAF) stimulated cell, activated stroma cell, and anti-PD-1 resistant cell.

Conclusion

The tumor gene expression characteristics of patients with hepatocellular carcinoma can be used as a basis for clinical patient classification. Different immune subtypes are closely related to survival prognosis. Different immune cell states of patients may lead to different disease risk levels. All these provide important references for the clinical identification and prognosis prediction of hepatocellular carcinoma.

High PD-L1 Level of Advanced Hepatic Lymphoepithelioma-like Carcinoma Response Favorably to Lenvatinib plus Toripalimab

Lymphoepithelioma‐like carcinoma (LELC) is an uncommon subtype of primary liver cancer with predominant lymphocyte infiltration and a relatively favorable outcome. However, no standard treatment for advanced hepatic LELC has been established. Here, we give a first report of a 60‐year‐old man with advanced hepatic LELC who had a high expression of PD‐L1 in tumor cells and a high level of tumor‐infiltrating leukocytes (TILs) in the tumor microenvironment (TME). After receiving six cycles of multiple receptor tyrosine kinase inhibitor (rTKI) with lenvatinib plus PD‐1 inhibitor toripalimab treatment, the patient achieved persistent partial response (PR). Our report indicates that advanced hepatic LELC with high expression of PD‐L1 may benefit from the combination of rTKI and PD‐L1/PD‐1 blockade. Therefore, this potential strategy should be considered when treating those rare liver cancers.

[Pathology of hepatocellular carcinoma]

Hepatocellular carcinoma (HCC) represents the third leading cause of cancer-related mortality worldwide and has a well-defined etiology. It develops in a stepwise process with morphologically defined precursor lesions. Typing of highly differentiated hepatocellular tumors is supported by immunohistological marker panel and the so-called matrix diagnosis. The recent World Health Organization (WHO) classification defined morpho-molecular HCC subtypes showing typical clinical and prognostic characteristics. If HCC subtyping is considered in future clinical studies of advanced HCC, this could help to introduce personalized HCC therapy. Currently, precision oncology is not available for HCC.

[Up-to-date Knowledge on the Pathological Diagnosis of Hepatocellular Carcinoma]

Hepatocellular carcinoma (HCC) has heterogeneous molecular and pathological features and biological behavior. Large-scale genetic studies of HCC were accumulated, and a pathological-molecular classification of HCC was proposed. Approximately 35% of HCCs can be classified into distinct histopathological subtypes according to their molecular characteristics. Among recently identified subtypes, macrotrabecular massive HCC, neutrophil-rich HCC, vessels encapsulating tumor clusters HCC, and progenitor phenotype HCC (HCC with CK19 expression) are associated with a poor prognosis, whereas the lymphocyte-rich HCC subtype is related to a better prognosis. This review provides up-to-date knowledge on the pathological diagnosis of HCC according to the updated World Health Organization Classification of Digestive System Tumors 5th ed.

Lymphoepithelioma-like Hepatocellular Carcinoma: a Case Report and Review of Literature

We report a case of hepatic lymphoepithelioma-like carcinoma-hepatocellular carcinoma subtype (LEL-HCC) in a 41-year-old man with chronic hepatitis C virus (HCV) infection. The patient presented with abdominal pain and further assessment revealed a hypoechoic mass on ultrasonography. Serum alpha-fetoprotein (AFP) was 13·6 ng/dl. The patient was diagnosed as hepatocellular carcinoma based on the established triphasic computed tomography (TCT) diagnostic criteria and he underwent a surgical resection of the mass. Microscopic examination showed sheets and cords of malignant epithelial cells intermixed with heavy lymphoid infiltrate, with more than 100 tumor-infiltrating lymphocytes (TILs) per 10 high-power-field (HPF). Based on immunohistochemical studies, the malignant cells were positive for Hep Par 1 and glypican 3, focally positive for cytokeratin 7 (CK7), and negative for cytokeratin 20 (CK20). TILs were diffusely positive for cluster of differentiation 3 CD3 with an approximately equal CD4/CD8 ratio. The patient was recurrence free at 25 months after surgery, as evident by CT and serum alpha-fetoprotein level. LEL-HCC is a rare variant of HCC with a relatively better prognosis. Exploring the potential for immune modulator-based therapy in this subset of tumors is highly recommended.

Evaluation of tumor mutational burden in small early hepatocellular carcinoma and progressed hepatocellular carcinoma

While researchers know that tumor mutational burden (TMB) is low in hepatocellular carcinoma (HCC), prior studies have not investigated TMB in cirrhosis, small early HCC and progressed HCC. HCC (n = 18) and cirrhosis (n = 6) cases were identified. TMB was determined by a 1.7 megabase, 409-gene next-generation sequencing panel. TMB values were defined as the number of nonsynonymous variants per megabase of sequence. There was no significant difference between cirrhosis versus small early HCC or between cohorts when stratified by size, early versus progressed, differentiation or morphology. There was a significant difference between cirrhosis and small early HCC versus progressed HCC (p = 0.045), suggesting TMB may be related to HCC progression. TMB similarities in small early HCC and background cirrhosis suggest TMB is not a useful tool for diagnosing small early HCC. Additional study is needed to address TMB in histological and molecular subsets of HCC.

Programmed cell death ligand 1 expression in a case of poorly differentiated lymphocyte-rich hepatocellular carcinoma

Our pathological study of a case of poorly differentiated lymphocyte-rich hepatocellular carcinoma suggested that immune checkpoint inhibitor may be an effective therapy. The histological type is an important factor in determining treatment choices.

Hepatocellular carcinoma: a clinical and pathological overview

HCC incidence rates have been rising in the past 3 decades and by 2025 > 1 million individuals will be affected annually. High-throughput sequencing technologies led to the identification of several molecular HCC subclasses that can be broadly grouped into 2 major subgroups, each characterized by specific morphological and phenotypical features. It is likely that this increasing knowledge and a more appropriate characterization of HCC at the pathological level will impact HCC patient management.

Checkpoint Inhibition in the Treatment of Unresectable, Advanced Lymphoepithelioma-like Hepatocellular Carcinoma

Lymphoepithelioma-like hepatocellular carcinoma (LEL-HCC) is a very rare neoplasm, with distinct epidemiologic, morphologic and clinical characteristics. Molecular mechanistic insight into the pathogenesis of this carcinoma suggests a pivotal role for the host immune system in the proliferation and progression of this tumor. However, while detailed genomic profiling of these hepatic tumors have revealed an intra-tumoral inflammatory mutational signature that may predispose to immune checkpoint inhibitor efficacy, no published report has described their use in this tumor type. Unfortunately, with near 100 cases of LEL-HCC reported in the literature to date and the majority of cases confined to localized and resectable disease, current evidence-based practices in the unresectable setting are lacking, with unknown benefit of chemotherapy or immunotherapy. We report on the case of a 68 year-old man with unresectable, advanced LEL-HCC who had evidence of disease stability after starting on the immune checkpoint inhibitor nivolumab. His disease response persisted off therapy for over a year and was potentially augmented by radiotherapy at the site of local progression. For this extremely rare tumor subtype, this case highlights the potential efficacy and safety of immune checkpoint blockade in LEL-HCC and reinforces the need for more robust, large-scale analysis of patients with these rare tumors to better evaluate treatment strategies and outcomes.

Pathologic and molecular features of hepatocellular carcinoma: An update

Morphological diversity and several new distinct pathologic subtypes of hepatocellular carcinoma (HCC) are now well-recognized. Recent advances in tumor genomics and transcriptomics have identified several recurrent somatic/genetic alterations that are closely related with histomorphological subtypes and have therefore, greatly improved our understanding of HCC pathogenesis. Pathologic subtyping allows for a diagnosis which is clinically helpful and can have important implication in patient prognostication as some of these subtypes are extremely aggressive with vascular invasion, early recurrence, and worst outcomes. Several targeted treatments are now being considered in HCC, and the reporting of subtypes may be quite useful for personalized therapeutic purpose. This manuscript reviews the recently identified histomorphological subtypes and molecular alterations in HCC.

Potential therapeutic targets in the tumor microenvironment of hepatocellular carcinoma: reversing the protumor effect of tumor-associated macrophages

In hepatocellular carcinoma patients, due to the microenvironmental specificity of liver, the tumor microenvironment exhibits high immunosuppression and drug resistance, resulting in excessive or insufficient responses to immunotherapy. The dynamic interactions between tumor cells and immune modulators in the TME significantly impact the occurrence and development of tumors, efficacy, and drug resistance, which can create a much more positive response to immunotherapy. Moreover, with the wide application of single-cell sequencing technology in the TME, increasing evidence shows an interaction network among cells. Sequencing results suggest that specific tumor-associated macrophages are a hub node, connecting different cell populations in the cell interaction network, and can could regulate tumor generation and antitumor immunity. This review focused on therapeutic targets that could be targeted to remodel the tumor microenvironment and reprogram the tumor-associated macrophage phenotype in hepatocellular carcinoma patients, thereby improving immunotherapeutic efficacy.

Immune microenvironment of hepatocellular carcinoma, intrahepatic cholangiocarcinoma and liver metastasis of colorectal adenocarcinoma: Relationship with histopathological and molecular classifications

Tumor tissue is composed of tumor cells and tumor stroma. Tumor stroma contains various immune cells and non-immune stromal cells, forming a complex tumor microenvironment which plays pivotal roles in regulating tumor growth. Recent successes in immunotherapies against tumors, including immune checkpoint inhibitors, have further raised interests in the immune microenvironment of liver carcinoma. The immune microenvironment of tumors is formed because of interactions among tumor cells, immune cells and non-immune stromal cells, including fibroblasts and endothelial cells. Different patterns of immune microenvironment are observed among different tumor subtypes, and their clinicopathological significance and intertumor/intratumor heterogeneity are being intensively studied. Here, we review the immune microenvironment of hepatocellular carcinoma, intrahepatic cholangiocarcinoma and liver metastasis of colorectal adenocarcinoma, focusing on its histopathological appearance, clinicopathological significance, and relationship with histological and molecular classifications. Understanding the comprehensive histopathological picture of a tumor immune microenvironment, in addition to molecular and genetic approaches, will further potentiate the effort for precision medicine in the era of tumor-targeting immunotherapy.

An update on subtypes of hepatocellular carcinoma: From morphology to molecular

The morphologic spectrum of hepatocellular carcinoma (HCC) is quite broad. While in about one-third of cases, the neoplasms can be categorized into meaningful subtypes based on morphology, a vast majority of these neoplasms are morphologically heterogeneous. With extensive tumor profiling, data has begun to emerge which can correlate specific morphologic features with underlying molecular signatures. A true morphologic subtype not only has reproducible H & E features, further supported by specific immunohistochemical or molecular signatures, but also has specific clinical implications and prognostic associations. Eight such morphologic subtypes are recognized by the 2019 WHO classification of tumors with a few more additional subtypes described in the literature. The goal of this review is to familiarize the reader with the morphologic subtypes and elaborate on the clinical and molecular associations of these neoplasms.

Hepatocellular carcinoma: making sense of morphological heterogeneity, growth patterns, and subtypes

Hepatocellular carcinomas are not a homogenous group of tumors but have multiple layers of heterogeneity. This heterogeneity has been studied for many years with the goal to individualize care for patients and has led to the identification of numerous hepatocellular carcinoma subtypes, defined by morphology and or molecular methods. This article reviews both gross and histological levels of heterogeneity within hepatocellular carcinoma, with a focus on histological findings, reviewing how different levels of histological heterogeneity are used as building blocks to construct morphological hepatocellular carcinoma subtypes. The current best practice for defining a morphological subtype is outlined. Then, the definition for thirteen distinct hepatocellular carcinoma subtypes is reviewed. For each of these subtypes, unresolved issues regarding their definitions are highlighted, including recommendations for these problematic areas. Finally, three methods for improving the research on hepatocellular carcinoma subtypes are proposed: (1) Use a systemic, rigorous approach for defining hepatocellular carcinoma subtypes (four-point model); (2) Once definitions for a subtype are established, it should be followed in research studies, as this common denominator enhances the ability to compare results between studies; and (3) Studies of subtypes will be more effective when morphological and molecular results are used in synergistic and iterative study designs where the results of one approach are used to refine and sharpen the results of the other. These and related efforts to better understand heterogeneity within hepatocellular carcinoma are the most promising avenue for improving patient care by individualizing patient care.

The CT and MRI Features of Primary Intrahepatic Lymphoepithelioma-Like Cholangiocarcinoma

OBJECTIVE. The purpose of our study was to retrospectively characterize the CT and MRI features of primary intrahepatic lymphoepithelioma-like cholangiocarcinoma (LELCC). MATERIALS AND METHODS. Eleven patients (10 women and one man; age range, 30-63 years) with 11 pathologically proven LELCCs were enrolled retrospectively from April 2016 to December 2018. Triphasic enhanced images were obtained of all patients: MR images of five patients, CT images of five patients, and both CT and MR images of one patient. The clinical data and CT and MRI findings were reviewed. RESULTS. All LELCC cases were associated with Epstein-Barr virus (EBV) infection. Eight of the 11 patients had hepatitis B virus (HBV) infection. The tumor diameter ranged from 1.1 to 8.7 cm. All tumors were well defined with a smooth or lobulated margin. A cystic area was noted in two of the 11 tumors. After the administration of contrast material, the tumors showed homogeneous (n = 7) or heterogeneous (n = 4) hypervascular arterial enhancement and gradual washout, delayed central scar or irregular enhancement (n = 9), delayed circular thin or incomplete pseudocapsule enhancement (n = 7), and homogeneous hypointensity in the hepatobiliary phase (n = 2). No cirrhosis, focal dilatation of intrahepatic ducts, or satellite nodules were detected. Lymphadenopathy were detected in four patients, appearing as hypervascular enhancement and no necrosis (even in multiple nodes > 3 cm) or as moderate peripheral enhancement and necrosis. CONCLUSION. A liver mass in a middle-aged woman with EBV and HBV infection that appears on CT and MRI to have a well-defined boundary and a combination of hypervascularity, washout, delayed intratumoral enhancement, or pseudocapsule enhancement may suggest an imaging diagnosis of primary LELCC. More cases are needed to better understand this disease.

[Hepatocellular carcinoma]

Hepatocellular carcinoma (HCC) belongs to the most prevalent and deadliest cancers worldwide. It can be attributed to well-defined risk factors (mainly chronic viral hepatitis and alcoholic/nonalcoholic steatohepatitis) leading to liver cirrhosis, a premalignant condition for the development of preneoplastic hepatocellular lesions and finally liver cancer. By applying strict morphological criteria and a panel of immunohistological markers, early HCC can be differentiated from its precursor lesions and other highly differentiated hepatocellular lesions even in most biopsy specimens. Integrative characterization led to the association of histological features and molecular subgroups of human HCC. This potentially relevant clinical development was recognized by the recently updated WHO classification of liver cancer resulting in the introduction of several HCC subtypes. These are characterized by a distinct combination of histological and molecular features, biological behavior, and clinical characteristics, allowing for a distinction from other HCC without specified features. Whether this development sets the corner stone for precision oncology of human HCC patients must be monitored.

Hepatocellular Carcinoma: Role of Pathology in the Era of Precision Medicine

Hepatocellular carcinoma (HCC) is a morphologically heterogeneous tumor with variable architectural growth patterns and several distinct histologic subtypes. Large-scale attempts have been made over the past decade to identify targetable genomic alterations in HCC; however, its translation into clinical personalized care remains a challenge to precision oncology. The role of pathology is no longer limited to confirmation of diagnosis when radiologic features are atypical. Pathology is now in a position to predict the underlying molecular alteration, prognosis, and behavior of HCC. This review outlines various aspects of histopathologic diagnosis and role of pathology in cutting-edge diagnostics of HCC.

Lymphoepithelioma-like carcinoma in liver not associated with Epstein-Barr virus: a report of 3 cases and literature review

Background

Lymphoepithelioma-like carcinoma is a rare distinctive variant of liver cancer with unique epidemiological and pathological characteristics, characterized by dense lymphocyte infiltration. It can be divided into lymphoepithelioma-like hepatocellular carcinoma and lymphoepithelioma-like intrahepatic cholangiocarcinoma. Existing research shows that the prognosis of this tumor is good. To date, only 101 cases have been reported.

Case presentation

The first patient was a 62-year-old Chinese man with hepatitis B virus infection who presented with a single lesion in the liver. The patient underwent surgical treatment and was discharged on the 4th day. The patient was diagnosed with combined lymphoepithelioma-like hepatocellular carcinoma and cholangiocarcinoma; he has been alive for 15 months. The second patient was a 63-year-old Chinese woman with right upper abdominal pain and hepatitis B virus infection. The imaging examination revealed a single lesion in the liver. The patient underwent surgical treatment and was discharged 1 week later. The patient was diagnosed with lymphoepithelioma-like hepatocellular carcinoma and was considered to have recurrence in the lymph nodes approximately 2 years after the operation. The patient underwent local radiotherapy; she has been alive for 60 months. The third patient was a 50-year-old Chinese man with hepatitis B virus infection who presented with a single lesion in the liver and two enlarged lymph nodes. The patient received liver puncture before surgery to indicate lymph node metastasis and experienced local recurrence after liver resection. The patient underwent chemotherapy and radiotherapy. The patient was diagnosed with lymphoepithelioma-like hepatocellular carcinoma. The patient was deceased at 24-month follow-up.

Conclusions

This article reports 3 cases without Epstein-Barr virus and reviews the current literature, which suggests even mixed pathological type or locally advanced cases of LELC with lymph node metastasis and postoperative recurrence should be actively treated for a longer survival period.

A comparability study of immunohistochemical assays for PD-L1 expression in hepatocellular carcinoma

Programmed death ligand 1 (PD-L1) protein expression by immunohistochemistry is a promising biomarker for PD-1/PD-L1 blockade in hepatocellular carcinoma. There are a number of commercially available PD-L1 assays. Our study aimed to compare the analytical performance of different PD-L1 assays and evaluate the reliability of pathologists in PD-L1 scoring. Consecutive sections from tumor samples from 55 patients with surgically resected primary hepatocellular carcinoma were stained with four standardized PD-L1 assays (22C3, 28-8, SP142, and SP263). We also correlated the PD-L1 protein level by immunohistochemistry with the mRNA level of those genes associated with tumor immune microenvironment by the NanoString platform. Five pathologists independently assessed PD-L1 expression on tumor cells [tumor proportion score] together with tumor-infiltrating immune cells (combined positive score). The 22C3, 28-8, and SP263 assays had comparable sensitivity in detecting PD-L1 expression, whereas the SP142 assay was the least sensitive assay. The inter-assay agreement measured by intraclass correlation coefficients for the tumor proportion score and combined positive score were 0.646 and 0.780, respectively. The inter-rater agreement was good to excellent (the overall intraclass correlation coefficient for the tumor proportion score and combined positive score was 0.946 and 0.809, respectively). Pathologists were less reliable in scoring combined positive score than tumor proportion score, particularly when using the SP142 assay. Up to 18% of samples were misclassified by individual pathologists in comparison to the consensus score at the cutoff of combined positive score ≥ 1. The combined positive score by the 22C3 assay demonstrated the strongest correlation with immune-related gene mRNA signatures, closely followed by combined positive scores by the 28-8 and SP263 assays. In conclusion, the 22C3, 28-8, and SP263 assays are highly concordant in PD-L1 scoring and suggest the interchangeability of these three assays. Further improvement of the accuracy in assessing PD-L1 expression at a low cutoff is still necessary.

Expression of Programmed Cell Death-Ligands in Hepatocellular Carcinoma: Correlation With Immune Microenvironment and Survival Outcomes

The quantity of programmed cell death-ligand 1 (PD-L1) is regarded as a predicting factor of clinical response to anti-PD-1 axis immunotherapy. However, the expression of PD-L1 and its prognostic value in hepatocellular carcinoma (HCC) patients remain debated. Meanwhile, the molecular features of PD-1's other ligand, namely PD-L2, as well as its correlation with clinicopathological parameters and HCC tumor microenvironment (TME), are still poorly understood. In this study, immunohistochemistry (IHC) data from 304 HCC patients were used to determine the clinicopathological features of PD-L1 and PD-L2 and their correlation with CD8⁺ T cells in HCC. Moreover, fresh clinical HCC samples were used to identify the immune cell subtypes expressing PD-L1 and PD-L2. By using The Cancer Genome Atlas (TCGA) dataset, we further assessed the correlation between mutation signature, copy number variation (CNV), number of neoepitopes, immune gene expression, immune/stromal cell infiltration to the expression of PD-L1 and PD-L2. While membrane expression of PD-L2 was observed in 19.1% of tumor samples, no obvious expression of PD-L1 was detected on tumor cell membranes. High expression of PD-L2 on tumor membranes and PD-L1 in immune stroma were both significantly associated with poorer overall survival (OS) and disease-free survival (DFS) outcomes. Flow cytometry analysis and immunofluorescence showed that macrophages were the main immune cell subtype expressing both PD-L1 and PD-L2. Moreover, positive expression of PD-Ls was correlated with higher CD8⁺ T cells infiltration in immune stroma. CNV analysis showed a similarity between PD-L1 and PD-L2 in affecting gene expression. In addition, higher levels of PD-Ls correlated with higher expression of immune related genes, enhanced cytolytic activity, and larger proportions of immune/stromal cell infiltration. Collectively, our study reveals the impact of both PD-L1 and PD-L2 on the HCC tumor microenvironment for the first time, providing insight for new therapeutic options.

Molecular and histological correlations in liver cancer

Hepatocellular carcinoma (HCC) is a highly heterogeneous cancer, both at the molecular and histological level. High-throughput sequencing and gene expression profiling have identified distinct transcriptomic subclasses and numerous recurrent genetic alterations; several HCC subtypes characterised by histological features have also been identified. HCC phenotype appears to be closely related to particular gene mutations, tumour subgroups and/or oncogenic pathways. Non-proliferative tumours display a well-differentiated phenotype. Among this molecular subgroup, CTNNB1-mutated HCCs constitute a homogeneous subtype, exhibiting cholestasis and microtrabecular and pseudoglandular architectural patterns. Another non-proliferative subtype has a gene expression pattern similar to that of mature hepatocytes (G4) and displays a steatohepatitic phenotype. In contrast, proliferative HCCs are most often poorly differentiated, and notably include tumours with progenitor features. A novel morphological variant of proliferative HCC - designated "macrotrabecular-massive" - was recently shown to be associated with angiogenesis activation and poor prognosis. Altogether, these findings may help to translate our knowledge of HCC biology into clinical practice, resulting in improved precision medicine for patients with this highly aggressive malignancy. This manuscript reviews the most recent data in this exciting field, discussing future directions and challenges.

Genomic landscape of lymphoepithelioma-like hepatocellular carcinoma

Lymphoepithelioma-like hepatocellular carcinoma (LEL-HCC) is a distinct variant of HCC that is characterized by dense tumor-infiltrating lymphocytes (TILs). Patients with LEL-HCC also show better clinical outcomes compared to conventional HCC (c-HCC), which is commonly presented with low TIL. Emerging evidence has begun to highlight tumor-intrinsic genetic abnormalities in the tumor-host immune interfaces. However, genome-wide characterization of LEL-HCC remains largely unexplored. Here, we defined the genomic landscape of 12 LEL-HCC using whole-exome sequencing, and further underpinned those genetic alterations related to an immune active microenvironment by comparing findings to 15 c-HCC that were sequenced in parallel. Overall, the mutational load between LEL-HCC and c-HCC was similar. Interestingly, SNV incidences of specific genes (CTNNB1, AXIN1, NOTCH1, and NOTCH2) were significantly higher in c-HCC than LEL-HCC, suggesting a plausible link between activated Wnt/β-catenin and Notch signaling pathways and immune avoidance. Marked focal amplification of chromosome 11q13.3 was prevalent in LEL-HCC. Using The Cancer Genome Atlas dataset, we further established oncogenes expressed from chromosome 11q13.3 (CCND1, FGF19, and FGF4) to be strongly associated with the immune checkpoint signature (CD274, PDCD1, BTLA, CTLA4, HAVCR2, IDO1, and LAG3). Our results have illustrated for the first time the somatic landscape of LEL-HCC, and highlighted molecular alterations that could be exploited in combinatory therapy with checkpoint inhibitors in targeting HCC. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The tumour microenvironment and immune milieu of cholangiocarcinoma

Tumour microenvironment is a complex, multicellular functional compartment that, particularly when assembled as an abundant desmoplastic reaction, may profoundly affect the proliferative and invasive abilities of epithelial cancer cells. Tumour microenvironment comprises not only stromal cells, mainly cancer-associated fibroblasts, but also immune cells of both the innate and adaptive system (tumour-associated macrophages, neutrophils, natural killer cells, and T and B lymphocytes), and endothelial cells. This results in an intricate web of mutual communications regulated by an extensively remodelled extracellular matrix, where the tumour cells are centrally engaged. In this regard, cholangiocarcinoma, in particular the intrahepatic variant, has become the focus of mounting interest in the last years, largely because of the lack of effective therapies despite its rising incidence and high mortality rates worldwide. On the other hand, recent studies in pancreatic cancer, which similarly to cholangiocarcinoma, is highly desmoplastic, have argued against a tumour-promoting function of the tumour microenvironment. In this review, we will discuss recent developments concerning the role of each cellular population and their multifaceted interplay with the malignant biliary epithelial counterpart. We ultimately hope to provide the working knowledge on how their manipulation may lead to a therapeutic gain in cholangiocarcinoma.

Synchronous hepatocellular carcinoma and lymphoepithelioma-like carcinoma arising from 2 different sites of the liver: A case report

RATIONALE

Most cases of primary liver cancer involve hepatocellular carcinoma (HCC). Lymphoepithelioma-like carcinoma (LELC) is defined as a tumor composed of undifferentiated epithelial cells with a prominent lymphoid infiltrate, which is rarely reported. Lymphoepithelioma-like HCC (LEL-HCC) is an uncommon variant of HCC, having an unclear process of development. Here, we report the first case involving simultaneous HCC and LEL-HCC.

PATIENT CONCERNS

A 77-year-old female was accidentally found to have a hypoechoic hepatic nodule via an abdominal ultrasound during a health examination. Abdominal computed tomography scan revealed 2 hepatic nodules with arterial phase enhancement and washout in the late phase.

DIAGNOSES

We diagnosed the case with 2 distinct liver nodules, HCC and LEL-HCC.

INTERVENTIONS

With suspicion of HCC, tumor resection (liver segments 4 and 5) was then performed. Histopathological examination of tumor 1 showed a moderately differentiated HCC and tumor 2 demonstrated a LEL-HCC. Immunohistochemically, the cells of tumor 2 were immunoreactive for cytokeratin (CK), CK7, and CK19. Epstein-Barr virus encoding small RNA (EBER) in situ hybridization results were negative.

OUTCOMES

Six months after resection, intrahepatic tumor recurrence was noted. Radiofrequency ablation was conducted.

LESSONS

This is an interesting case providing circumstantial evidence of simultaneous development of HCC and LEL-HCC in distinct nodules of the liver with a background of chronic hepatitis B virus infection.

Programmed death-ligand 1 is upregulated in intrahepatic lymphoepithelioma-like cholangiocarcinoma

Intrahepatic lymphoepithelioma-like cholangiocarcinoma (LELCC) is a rare variant of cholangiocarcinoma. Here, we report the largest single series of LELCC cases yet studied (n = 13). We retrospectively analyzed the clinical data of the 13 patients and measured the expression of programmed death-ligand 1 (PD-L1) in tumors using immunohistochemical staining. We also analyzed 15 cases of conventional intrahepatic cholangiocarcinoma (IHCC) for comparison. We found that eight patients with LELCC were infected with Epstein-Barr Virus (EBV), and EBV infection correlated with poor prognosis in LELCC. Four patients among the five (80.0%) without EBV had a history of chronic viral hepatitis B. None of the 15 cases of conventional cholangiocarcinoma were positive for EBV. PD-L1 was expressed in both the tumor cells and tumor-infiltrating immune cells in LELCC patients at higher levels than in IHCC patients (P < 0.05). These observations suggest that EBV infection may promote the development of LELCC, and that PD-L1 may be a potential therapeutic target for treatment of EBV-associated LELCC.

Lymphoepithelioma-like hepatocellular carcinoma: A case report and brief review of literature

RATIONAL

Lymphoepithelioma-like hepatocellular carcinoma (LEL-HCC) is a rare variant of hepatocellular carcinoma (HCC). To date, few cases have been reported in the literature, and almost no report in analyzing the different features of LEL-HCC.

PATIENT CONCERNS

We describe a 37-year-old female patient with a 32 × 30 mm mass in the right liver.

INTERVENTIONS

Complete surgical resection of the lesion was performed.

DIAGNOSES

Histopathological examination of the resected tumor revealed undifferentiated HCC cells with significant lymphocytes infiltration. Immunohistochemically, the tumor cells were positive for AFP (alpha fetoprotein), hepatocyte, CK8, and glypican-3. The patient was diagnosed with LEL-HCC.

OUTCOMES

The patient had a favorable clinical outcome, and was free from tumor recurrence after a 52-months follow-up.

LESSONS

Our case was the youngest patient of all the reported cases, and the third case who was infected with both hepatitis B virus (HBV) and hepatitis C virus (HCV). LEL-HCC is a rare variant of HCC, with a relatively favorable prognosis. Further research recruiting more patients is required to determine the accurate causes and mechanism of LEL-HCC.

Morphologic Subtypes of Hepatocellular Carcinoma

Hepatocellular carcinomas can be further divided into distinct subtypes that provide important clinical information and biological insights. These subtypes are distinct from growth patterns and are on based on morphologic and molecular findings. There are 12 reasonably well-defined subtypes as well as 6 provisional subtypes, together making up 35% of all hepatocellular carcinomas. These subtypes are discussed, with an emphasis on their definitions and the key morphologic findings.

Lymphoepithelioma-Like Carcinoma in Liver

Liver cancer, primarily encompassing hepatocellular carcinoma and intrahepatic cholangiocarcinoma, has become the second leading cause of worldwide cancer-related death during the past two decades. Lymphoepithelioma-like carcinomas (LELCs) are defined as tumors composed of undifferentiated epithelial cells with a prominent lymphoid infiltrate, and can arise in the liver as hepatocellular or cholangiocarcinoma forms. Patients with liver LELC display distinctive demographics and tumor characteristics. LELCs also appear to be associated with strikingly better outcomes compared to typical liver cancers, with 5-year survival rates of 57% to 100% versus 12% to 68%, respectively. Liver LELCs represent a unique model of immune response in liver cancer. Data on LELCs of the liver remain limited, and future comprehensive studies are needed to further elucidate this disease, which could ultimately offer precious insights for immunotherapeutic strategies in liver cancer.

Lymphoepithelioma-Like Cholangiocarcinoma Associated With HCV: A Case Report and a Review of the Literature

Lymphoepithelioma-like carcinoma is a particular form of undifferentiated carcinoma characterized by a prominent lymphoid stroma that was originally described in the nasopharynx. We present a case of hepatitis C virus (HCV)–associated lymphoepithelioma-like cholangiocarcinoma (LEL-CC), located at the liver, in a patient with history of malignancy. A 79-year-old man underwent partial hepatectomy with lymphadenectomy for a suspected metastasis of colon cancer 2.5 years after hemicolectomy for advanced colon cancer followed by adjuvant chemotherapy. The resected tumor was diagnosed as LEL-CC via a distinct histologic pattern with dense lymphoplasma cell infiltration. According to the available literature, our report describes a rare cases of HCV-associated LEL-CC that coexisted with other malignancy and that was associated with survival for more than 3 years after surgery, suggesting that surgical resection may be the recommended therapeutic option for LEL-CC to provide a definitive diagnosis as well as obtain a good prognosis, even in advanced stages of LEL-CC.

Programmed death ligand 1 expression in hepatocellular carcinoma: Relationship With clinical and pathological features

The prognosis of hepatocellular carcinoma (HCC) remains poor, with only one third of patients eligible for curative treatments and very limited survival benefits with the use of sorafenib, the current standard of care for advanced disease. Recently, agents targeting the programmed death ligand 1 (PD-L1)/programmed death receptor 1 (PD-1) immune checkpoint were shown to display impressive antitumor activity in various solid or hematological malignancies, including HCC. PD-L1 immunohistochemical expression is thought to represent a biomarker predictive of drug sensitivity. Here, we investigated PD-L1 expression in a series of 217 HCCs and correlated our results with clinical and histological features and immunohistochemical markers (PD-1, cytokeratin 19, glutamine synthetase, and β-catenin expression). PD-L1 expression by neoplastic cells was significantly associated with common markers of tumor aggressiveness (high serum alpha-fetoprotein levels, P = 0.038; satellite nodules, P < 0.001; macrovascular invasion, P < 0.001; microvascular invasion, P < 0.001; poor differentiation, P < 0.001) and with the progenitor subtype of HCC (cytokeratin 19 expression, P = 0.031). High PD-L1 expression by inflammatory cells from the tumor microenvironment also correlated with high serum alpha-fetoprotein levels (P < 0.001), macrovascular invasion (P = 0.001), poor differentiation (P = 0.001), high PD-1 expression (P < 0.001), and the so-called lymphoepithelioma-like histological subtype of HCC (P = 0.003).

CONCLUSION

PD-L1 expression by either neoplastic or intratumoral inflammatory cells is related to tumor aggressiveness and suggests that the response to treatments targeting the PD-L1/PD-1 immune checkpoint could be restricted to particular HCC variants; thus, enrichment of these tumor subtypes in future clinical trials should be considered. (Hepatology 2016;64:2038-2046).

Lymphoepithelioma-like hepatocellular carcinoma: Case report and review of the literature

Lymphoepithelioma-like hepatocellular carcinoma (LEL-HCC) is a rare form of undifferentiated carcinoma of the liver characterized by the presence of an abundant lymphoid infiltrate. Here, a case of LEL-HCC is described. An 81-year-old woman with a chronic hepatitis C infection was referred to the general surgery department of our hospital in August 2013 with a diagnosis of HCC. A past ultrasound examination had revealed a 60 mm-diameter nodular lesion in the third segment of the liver. After a needle biopsy, the lesion was diagnosed as HCC. The patient underwent surgery with a liver segmentectomy. Two additional nodes on the gastric wall were detected during the surgical operation. The histology of the removed specimen showed a poorly differentiated HCC with significant lymphoid stroma. Immunohistochemical studies revealed that the epithelial component was reactive for CK CAM5.2, CK8, CK18, CEA (polyclonal) and was focally positive for hepar-1 and that the lymphoid infiltrate was positive for CD3, CD4 and CD8. The tumor cells were negative for Epstein-Barr virus. The gastric nodes were ultimately determined to be two small gastrointestinal stromal tumors (GISTs). The synchronous occurrence of HCC and GIST is another very uncommon finding rarely described in the literature. Here, we report the clinicopathological features of our case, along with a review of the few cases present in the literature.

Hepatoid carcinoma of the pancreas with lymphoid stroma: first description of the clinical, morphological, immunohistochemical, and molecular characteristics of an unusual pancreatic carcinoma

We report a case of tumour in the head of the pancreas observed in a 57-year-old man with a history of worsening jaundice and elevated alpha-fetoprotein (AFP) serum level, who underwent Whipple pancreatoduodenectomy. Histologically, the tumour was predominantly composed of solid sheets of large eosinophilic cells with a prominent lymphoid infiltration without association neither with DNA microsatellite instability nor Epstein-Barr virus infection. The tumour was diffusely and strongly positive for hepatocyte paraffin-1 (Hep Par-1) and glypican-3 leading to the diagnosis of hepatoid carcinoma. Strong cytoplasmic staining for AFP was focally observed. Moreover, tumour cells showed countless cytoplasmic eosinophilic globules immunoreactive for the stress protein p62. A primary hepatocellular carcinoma of the liver was ruled out by careful clinical analysis. Hepatoid carcinoma is an extremely rare pancreatic neoplasm, and here, we describe the first case of such variant associated with lymphoid stroma. The characteristic histologic features and the immunophenotypic profile help in distinguishing this carcinoma from other pancreatic tumours, notably from medullary carcinoma.