Liver Inflammation and Hepatobiliary Cancers.

Immune regulation has an important role in cancer development, particularly in organs with continuous exposure to environmental pathogens, such as the liver and gastrointestinal tract. Chronic liver inflammation can lead to the development of hepatobiliary cancers, namely hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (iCCA), or combined HCC (cHCC)-CCA. In this review, we discuss the link between oxidative stress and the hepatic immune compartments, as well as how these factors trigger hepatocyte damage, proliferation, and eventually cancer initiation and its sustainment. We further give an overview of new anticancer therapies based on immunomodulation.

NLRP3 receptor contributes to protection against experimental antigen-mediated cholangitis.

Inflammatory diseases of the bile ducts like primary sclerosing colangitis (PSC) are characterized by a robust cellular response targeting the biliary epithelium leading to chronic inflammation and fibrosis. Driving fibro-inflammatory diseases, NOD-like receptors such as NLRP3 have been identified as a central component to immune-mediated pathology. However, to date the role of NLRP3 in biliary diseases has been poorly explored. Here, we addressed the role of NLRP3 in the OVAbil mouse model of antigen-mediated cholangitis. As obesity continues to spread worldwide, we also evaluated the NLRP3 response in experimental cholangitis after high-fat diet exposure. We compared the extent of histopathological liver damage between OVAbil and OVAbilxNLRP3-/- mice after either a standard chow or a high-fat diet. Infiltrating immune cells were characterized by flow cytometry and levels of cytokines, chemokines and liver enzymes in blood samples were analyzed at the end of the experiment. We observed a more severe histopathological phenotype of cholangitis in absence of NLRP3, characterized by loss of bile ducts and larger inflammatory foci and higher levels of IL- 6 and CXCL10 as compared with NLRP3 sufficient mice. This phenotype was further exaggerated in the context of obesity, where cholangitis induced in NLRP3-deficient obese mice resulted in further exacerbated histopathology and increased levels of IL-13 and TNFα, suggesting a diet-specific profile. The absence of NLRP3 caused a supressed IL-17 response. In summary, our data suggest that activation of NLRP3 attenuates this antigen-mediated OVAbil model of cholangitis.

Immune system and cholangiocytes: A puzzling affair in primary biliary cholangitis.

Primary biliary cholangitis (PBC) is a cholestatic liver disease characterized by the destruction of the small and medium bile ducts. Its pathogenesis is still unknown. Despite the genome wide association study findings, the therapies targeting the cytokines pathway, tested so far, have failed. The concept of the biliary epithelium as a key player of the PBC pathogenesis has emerged over the last few years. It is now well accepted that the biliary epithelial cells (BECs) actively participate to the genesis of the damage. The chronic stimulation of BECs via microbes and bile changes the cell phenotype toward an active state, which, across the production of proinflammatory mediators, can recruit, retain, and activate immune cells. The consequent immune system activation can in turn damage BECs. Thus, the crosstalk between both innate and adaptive immune cells and the biliary epithelium creates a paracrine loop responsible for the disease progression. In this review, we summarize the evidence provided in literature about the role of BECs and the immune system in the pathogenesis of PBC. We also dissect the relationship between the immune system and the BECs, focusing on the unanswered questions and the future potential directions of the translational research and the cellular therapy in this area.

Nomogram based on inflammatory indices for differentiating intrahepatic cholangiocarcinoma from hepatocellular carcinoma.

OBJECTIVE: To establish nomogram based on inflammatory indices for differentiating intrahepatic cholangiocarcinoma (ICC) from hepatocellular carcinoma (HCC). METHODS: A cohort of 422 patients with HCC or ICC hospitalized at Xiangya Hospital between January 2014 and December 2018 was included in the study. Univariate and multivariate analysis was performed to identify the independent differential factors. Through combining these independent differential factors, a nomogram was established for differential diagnosis between ICC and HCC. The accuracy of nomogram was evaluated by using receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA). The results were validated using a prospective study on 98 consecutive patients operated on from January 2019 to November 2019 at the same institution. RESULTS: Sex (OR = 9.001, 95% CI: 3.268-24.792, P < .001), hepatitis (OR = 0.323, 95% CI: 0.121-0.860, P = .024), alpha-fetoprotein (AFP) (OR = 0.997, 95% CI: 0.995-1.000, P = .046), carbohydrate antigen 19-9 (CA199) (OR = 1.016, 95% CI: 1.007-1.025, P < .001), and aspartate transaminase-to-neutrophil ratio index (ANRI) (OR = 0.904, 95% CI: 0.843-0.969, P = .004) were the independent differential factors for ICC. Nomogram was established with well-fitted calibration curves through incorporating these 5 factors. Comparing model 1 including gender, hepatitis, AFP, and CA199 (C index = 0.903, 95% CI: 0.849-0.957) and model 2 enrolling AFP and CA199 (C index = 0.850, 95% CI: 0.791-0.908), the nomogram showed a better discrimination between ICC and HCC, with a C index of 0.920 (95% CI, 0.872-0.968). The results were consistent in the validation cohort. DCA also confirmed the conclusion. CONCLUSION: A nomogram was established for the differential diagnosis between ICC and HCC preoperatively, and better therapeutic choice would be made if it was applied in clinical practice.

Immunological abnormalities in patients with primary biliary cholangitis.

Primary biliary cholangitis (PBC), an autoimmune liver disease occurring predominantly in women, is characterized by high titers of serum anti-mitochondrial antibodies (AMAs) and progressive intrahepatic cholestasis. The immune system plays a critical role in PBC pathogenesis and a variety of immune cell subsets have been shown to infiltrate the portal tract areas of patients with PBC. Amongst the participating immune cells, CD4 T cells are important cytokine-producing cells that foster an inflammatory microenvironment. Specifically, these cells orchestrate activation of other immune cells, including autoreactive effector CD8 T cells that cause biliary epithelial cell (BEC) injury and B cells that produce large quantities of AMAs. Meanwhile, other immune cells, including dendritic cells (DCs), natural killer (NK) cells, NKT cells, monocytes, and macrophages are also important in PBC pathogenesis. Activation of these cells initiates and perpetuates bile duct damage in PBC patients, leading to intrahepatic cholestasis, hepatic damage, liver fibrosis, and eventually cirrhosis or even liver failure. Taken together, the body of accumulated clinical and experimental evidence has enhanced our understanding of the immunopathogenesis of PBC and suggests that immunotherapy may be a promising treatment option. Herein, we summarize current knowledge regarding immunological abnormalities of PBC patients, with emphasis on underlying pathogenic mechanisms. The differential immune response which occurs over decades of disease activity suggests that different therapies may be needed at different stages of disease.

Programmed cell death ligand 1 (PD-L1, CD274) in cholangiocarcinoma - correlation with clinicopathological data and comparison of antibodies.

BACKGROUND: Cholangiocarcinoma (CCA) may arise in the intra- or extrahepatic biliary tract and is associated with a poor prognosis. Despite recent advances, to date there is still no established targeted therapeutic approach available. Non-surgical therapeutic agents are urgently needed, as most patients are non-eligible to surgical resection. Anti-PD-L1 therapy prevents cancer cells from evading the immune system and has emerged as a new treatment option in several cancer entities. Recently, PD-L1 expression has been analyzed in comparably small CCA patient cohorts. However, a systematic validation of different PD-L1 antibodies has not been performed in CCA so far. METHODS: We stained a tissue microarray consisting of 170 patients, including 72 intrahepatic cholangiocarcinomas (iCCAs), 57 perihilar cholangiocarcinomas (pCCAs) and 41 distal cholangiocarcinomas (dCCAs) by immunohistochemistry and evaluated PD-L1 positivity in tumor and stromal cells. We analyzed three different PD-L1 antibodies (clones 28-8, SP142, and SP263) that are frequently used and recommended for predictive diagnostic testing in other cancer types. RESULTS: For PD-L1 antibody clone SP263, 5% of iCCAs, 4% of pCCAs and 3% of dCCAs exhibited PD-L1 expression on tumor cells, thereby showing the highest frequencies of PD-L1 positivity. Accordingly, highest PD-L1 positivity rates of stromal cells with 31% in iCCA, 40% in pCCA and 61% in dCCA were detected for clone SP263. Agreement of PD-L1 positivity in tumor cells was moderate for clone 28-8 and SP263 (κ = 0.44) and poor between 28-8 and SP142 (κ = 0.13), as well as  SP142 and SP263 (κ = 0.11), respectively. Statistical analyses of PD-L1 expression (clone SP263) on tumor cells with clinicopathological data revealed a positive correlation with shortened overall survival in CCA patients. CONCLUSIONS: Selection of appropriate PD-L1 antibodies and careful evaluation of immunohistochemical staining patterns have a significant impact on PD-L1 testing in CCA. Clinical trials are necessary to investigate the putative beneficial effects of PD-L1 targeted immunotherapy in CCA patients.

Immunometabolism: A novel perspective of liver cancer microenvironment and its influence on tumor progression.

The initiation and progression of liver cancer, including hepatocellular carcinoma and intrahepatic cholangiocarcinoma, are dependent on its tumor microenvironment. Immune cells are key players in the liver cancer microenvironment and show complicated crosstalk with cancer cells. Emerging evidence has shown that the functions of immune cells are closely related to cell metabolism. However, the effects of metabolic changes of immune cells on liver cancer progression are largely undefined. In this review, we summarize the recent findings of immunometabolism and relate these findings to liver cancer progression. We also explore the translation of the understanding of immunometabolism for clinical use.

Intrahepatic Cholangiocarcinomas Have Histologically and Immunophenotypically Distinct Small and Large Duct Patterns.

Intrahepatic cholangiocarcinomas are histologically heterogenous. Using a cohort of 184 clinically defined, resected intrahepatic cholangiocarcinomas, we retrospectively classified the histology into 4 subtypes: large duct (LD), small duct (SD) (predominantly tubular [SD1] or predominantly anastomosing/cholangiolar, [SD2]), or indeterminate. Then, we tested the 4 subtypes for associations with risk factors, patient outcomes, histology, and immunophenotypic characteristics. SD was the most common (84%; 24% SD1 and 60% SD2) with lower proportions of LD (8%), and indeterminate (8%). Primary sclerosing cholangitis was rare (2%), but correlated with LD (P=0.005). Chronic hepatitis, frequent alcohol use, smoking, and steatosis had no histologic association. LD was associated with mucin production (P<0.001), perineural invasion (P=0.002), CA19-9 staining (P<0.001), CK7, CK19, CD56 immunophenotype (P=0.005), and negative albumin RNA in situ hybridization (P<0.001). SD was histologically nodular (P=0.019), sclerotic (P<0.001), hepatoid (P=0.042), and infiltrative at the interface with hepatocytes (P<0.001). Albumin was positive in 71% of SD and 18% of LD (P=0.0021). Most albumin positive tumors (85%) lacked extracellular mucin (P<0.001). S100P expression did not associate with subtype (P>0.05). There was no difference in disease-specific or recurrence-free survival among the subtypes. Periductal infiltration and American Joint Committee on Cancer eighth edition pT stage predicted survival by multivariable analysis accounting for gross configuration, pT stage, and histologic type. pT2 had worse outcome relative to other pT stages. Significant differences in histology and albumin expression distinguish LD from SD, but there is insufficient evidence to support further subclassification of SD.

Interleukin-6 promotes the migration and cellular senescence and inhibits apoptosis of human intrahepatic biliary epithelial cells.

Biliary epithelial cells (BEC) are closely related to some immune regulatory bile duct diseases. However, the complexity and polymorphism of the morphology and function of bile duct cells have hindered further investigation. Therefore, the aim of this study is to investigate how interleukin-6 (IL-6) affects the migration, cellular senescence, and apoptosis of human intrahepatic biliary epithelial cells (HIBECs). The HIBECs were stimulated by different concentrations of IL-6 (0, 5, 10, 15, and 20 ng/mL, respectively). Transwell assay was performed in order to measure the migration abilities, positive ß-Galactosidase staining for the cellular senescence of HIBECs, MTT assay for changes of proliferation after IL-6 treatment and flow cytometry for cell cycle and apoptosis. The reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting were conducted in order to detect the mRNA and protein expressions of epithelial-mesenchymal transition (EMT) markers in HIBECs. In comparison to the 0 ng/mL group, in the 5, 10, 15, and 20 ng/mL groups, a significant increase in the number of migratory HIBECs, proliferation, along with mRNA and protein expressions of EMT markers was observed. While the mRNA and protein expressions of epithelial markers, the number of ß-galactosidase positive staining cells, as well as apoptosis rate of HIBECs dramatic decreased. Further, the aforementioned changes were significantly more evident in the 15 and 20 ng/mL groups in comparison to the 5 and 10 ng/mL groups. IL-6 may stimulate EMT, enhance the migration and proliferation, and inhibit apoptosis of HIBECs, thus delaying cellular senescence.

From pathogenesis to novel therapies in the treatment of primary biliary cholangitis.

INTRODUCTION: Primary biliary cholangitis (PBC) is an immune-mediated liver disease characterized by chronic inflammation of the intrahepatic bile ducts, causing progressive ductopenia, cholestasis and fibrosis, and leading to liver failure. Ursodeoxycholic acid (UDCA) is the first-line therapy for the treatment of PBC patients. This is effective in majority of patients; however, up to 20 percent of patients have an incomplete response to UDCA therapy and have a reduced prognosis as compared to healthy individuals. Obeticholic acid (OCA) has been recently registered as second-line therapy for patients with incomplete response to UDCA, with plans to demonstrate the long-term clinical efficacy. Areas covered: Recent evolution in our understanding of disease mechanisms is leading to the advent of new and re-purposed therapeutic agents targeting key processes in the etiopathogenesis. Several therapeutic targets have been proposed which can be categorized into three compartments: immune, biliary and fibrosis. In this review we describe the main biological mechanisms underpinning disease development and progression in PBC and the new targeted therapies on the horizon. Expert commentary: Testing new drugs towards hard clinical endpoints is challenging in PBC due to its low prevalence and the slow progression of the disease. Novel promising biomarkers are under study and should be evaluated as surrogate endpoints in clinical trials.

Enhanced cytotoxic activity of effector T-cells against cholangiocarcinoma by dendritic cells pulsed with pooled mRNA.

Cholangiocarcinoma is a malignancy of bile duct epithelia with an increasing in incidence rate worldwide. Surgery is the only curative treatment, while adjuvant chemotherapy and radiotherapy render poor responses. Cell-based immunotherapy is a potential strategy for cholangiocarcinoma treatment. However, variation of tumor antigens in cholangiocarcinoma leads to the ineffectiveness of cell-based immunotherapy. In this study, we examined the activation of effector T-cells by dendritic cells pulsed with protein lysate or total RNA from cholangiocarcinoma cell lines for their cytolytic activity against cholangiocarcinoma. Broad-spectrum antigen types with respect to RNA antigen sources were obtained from combination of three cholangiocarcinoma cell lines (KKU-213, KKU-100, and KKU-055). Compared with protein lysate-pulsed dendritic cells, total RNA-pulsed dendritic cells induced anti-tumor effector T-cell response with higher killing ability to KKU-100 and KKU-213 cells compared with protein lysate-pulsed dendritic cells. Moreover, pooled messenger RNA from three cholangiocarcinoma cell lines significantly increased the specific killing capacity of activated lymphocytes against KKU-213 cells. These results suggest that activation of anti-tumor effector T-cells against cholangiocarcinoma by RNA-pulsed dendritic cells is more effective than that by protein lysate-pulsed dendritic cells. In addition, pulsing dendritic cells with pooled messenger RNA from multiple cell lines enhanced the efficacy of a cellular immune response against cholangiocarcinoma.

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.

TLR2 promotes human intrahepatic cholangiocarcinoma cell migration and invasion by modulating NF-κB pathway-mediated inflammatory responses.

Intrahepatic cholangiocarcinoma (ICC) is a rare and aggressive malignancy that is often diagnosed at advanced stages, which limits treatment options. Despite its increasing incidence and mortality worldwide, the pathogenesis of ICC is not well understood. Here, we examined the effect of the dysregulation of innate immune responses on carcinogenesis by investigating the role of toll-like receptor (TLR)2 in the pathogenesis and invasiveness of ICC and explored the underlying mechanisms. Immunohistochemical analysis, real-time PCR, and western blotting showed higher TLR2 levels in ICC tissues and cell lines. Silencing and overexpression experiments indicated that TLR2 promotes ICC migration and invasion, induces the expression of epithelial-to-mesenchymal transition (EMT) markers, and upregulates the proinflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1ß concomitant with the activation of NF-κB signaling. Inhibition of NF-κB activity abolished the effect of TLR2 on EMT, invasion and migration, and the TLR2-induced upregulation of proinflammatory cytokines, and suppressed the effect of exogenous TNF-α and IL-6 on restoring EMT, migration and invasion in the presence of TLR2. Taken together, our results indicate that TLR2 has protumorigenic and prometastatic effects in ICC through the upregulation of inflammatory cytokines induced by the activation of NF-κB signaling, suggesting potential novel therapeutic targets for the treatment of ICC.

Biliary epithelium and liver B cells exposed to bacteria activate intrahepatic MAIT cells through MR1.

BACKGROUND & AIMS: Mucosal-Associated Invariant T (MAIT) cells are innate-like T cells characterised by the invariant TCR-chain, Vα7.2-Jα33, and are restricted by MR1, which presents bacterial vitamin B metabolites. They are important for antibacterial immunity at mucosal sites; however, detailed characteristics of liver-infiltrating MAIT (LI-MAIT) and their role in biliary immune surveillance remain unexplored. METHODS: The phenotype and intrahepatic localisation of human LI-MAIT cells was examined in diseased and normal livers. MAIT cell activation in response to E. coli-exposed macrophages, biliary epithelial cells (BEC) and liver B cells was assessed with/without anti-MR1. RESULTS: Intrahepatic MAIT cells predominantly localised to bile ducts in the portal tracts. Consistent with this distribution, they expressed biliary tropic chemokine receptors CCR6, CXCR6, and integrin αEß7. LI-MAIT cells were also present in the hepatic sinusoids and possessed tissue-homing chemokine receptor CXCR3 and integrins LFA-1 and VLA-4, suggesting their recruitment via hepatic sinusoids. LI-MAIT cells were enriched in the parenchyma of acute liver failure livers compared to chronic diseased livers. LI-MAIT cells had an activated, effector memory phenotype, expressed α4ß7 and receptors for IL-12, IL-18, and IL-23. Importantly, in response to E. coli-exposed macrophages, liver B cells and BEC, MAIT cells upregulated IFN-γ and CD40 Ligand and degranulated in an MR1-dependent, cytokine-independent manner. In addition, diseased liver MAIT cells expressed T-bet and RORγt and the cytokines IFN-γ, TNF-α, and IL-17. CONCLUSIONS: Our findings provide the first evidence of an immune surveillance effector response for MAIT cells towards BEC in human liver; thus they could be manipulated for treatment of biliary disease in the future.

PD-L1 and HLA Class I Antigen Expression and Clinical Course of the Disease in Intrahepatic Cholangiocarcinoma.

PURPOSE: More effective therapy is needed for intrahepatic cholangiocarcinoma (ICC). The encouraging clinical results obtained with checkpoint molecule-specific monoclonal antibodies (mAb) have prompted us to investigate whether this type of immunotherapy may be applicable to ICC. The aims of this study were to determine whether (i) patients mount a T-cell immune response to their ICC, (ii) checkpoint molecules are expressed on both T cells and tumor cells, and (iii) tumor cells are susceptible to recognition by cognate T cells. EXPERIMENTAL DESIGN: Twenty-seven ICC tumors were analyzed for (i) lymphocyte infiltrate, (ii) HLA class I and HLA class II expression, and (iii) PD-1 and PD-L1 expression by T cells and ICC cells, respectively. The results of this analysis were correlated with the clinicopathologic characteristics of the patients investigated. RESULTS: Lymphocyte infiltrates were identified in all tumors. PD-L1 expression and HLA class I antigen expression by ICC cells was observed in 8 and 11, respectively, of the 27 tumors analyzed. HLA class I antigen expression correlated with CD8(+) T-cell infiltrate. Furthermore, positive HLA class I antigen expression in combination with negative/rare PD-L1 expression was associated with favorable clinical course of the disease. CONCLUSIONS: ICC patients are likely to mount a T-cell immune response against their own tumors. Defects in HLA class I antigen expression in combination with PD-L1 expression by ICC cells provide them with an immune escape mechanism. This mechanism justifies the implementation of immunotherapy with checkpoint molecule-specific mAbs in patients bearing ICC tumors without defects in HLA class I antigen expression.

A Promising Serum Autoantibody Marker, Anti-Heat Shock Protein 90α, for Cholangiocarcinoma.

The present study was designed to investigate cholangiocarcinoma (CCA) antibodies in hamster serum. Hamster CCA cell lines were processed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. A candidate biomarker was confirmed by immunoprecipitation and western blot, and was further analyzed using ELISA and sera from normal control hamsters, hamsters with opisthorchiasis and hamsters with various stages of CCA, as well as from CCA patients and healthy individuals. One candidate marker was identified as HSP90α, as indicated by a high level of anti-HSP90α in hamster CCA sera. It was found that the levels of anti-HSP90α were specifically elevated in the sera of hamsters with CCA compared with other groups and progressively increased with the clinical stage. At the cut-off point of 0.4850 on the receiver operating characteristic curve, anti-HSP90α could discriminate CCA from healthy control groups with a sensitivity of 76.2%, specificity of 71.4% and total accuracy 75.5%. In the present study, we have shown that anti-HSP90α may be a potential useful serum biomarker to discriminate CCA cases from healthy persons.

Protective effect of theaflavin-enriched black tea extracts against dimethylnitrosamine-induced liver fibrosis in rats.

Liver cirrhosis is responsible for hepatic fibrosis resulting in high mortality and is also a risk factor for developing hepatocellular carcinoma (HCC), which is the fifth most common cancer in men and the seventh in women globally. Several studies have found effective anti-cancer activities of theaflavins, the major black tea polyphenols. The objective of this study was to investigate the protective effects of theaflavin-enriched black tea extracts (TF-BTE) on hepatic fibrosis induced by dimethylnitrosamine (DMN) administration in Sprague-Dawley (SD) rats. Treatment of SD rats with DMN (10 mg per kg bw) for 4 weeks produced inflammation and remarkable liver fibrosis assessed by serum biochemistry and histopathological examination. Fibrotic status and the activation of hepatic stellate cells were improved by oral administration of 40% theaflavins in black tea extracts (40% TF-BTE) as evidenced by histopathological examination. Oral administration of 40% TF-BTE at a low dose of 50 mg per kg bw per day and a high dose of 100 mg per kg bw per day attenuated the DMN-induced elevation of serum GOT (glutamate oxaloacetate transaminase) and GPT (glutamic pyruvic transaminase) levels and reduced necrosis, bile duct proliferation, and inflammation. Western blot analyses revealed that TF-BTE inhibited the expression of liver alpha-smooth muscle actin (α-SMA) and transforming growth factor-ß1 (TGF-ß1) protein. The histochemical examination showed the inhibitory effect of TF-BTE on the p-Smad3 expression. Overall, these data demonstrated that TF-BTE exhibited hepatoprotective effects on experimental fibrosis, potentially by inhibiting the TGF-ß1/Smad signaling.

Immunoglobulin G4-related sclerosing cholangitis mimicking hilar cholangiocarcinoma diagnosed with following bile duct resection: report of a case.

We report a rare case of immunoglobulin G4 (IgG4)-related sclerosing cholangitis without other organ involvement. A 69-year-old-man was referred for the evaluation of jaundice. Computed tomography revealed thickening of the bile duct wall, compressing the right portal vein. Endoscopic retrograde cholangiopancreatography showed a lesion extending from the proximal confluence of the common bile duct to the left and right hepatic ducts. Intraductal ultrasonography showed a bile duct mass invading the portal vein. Hilar bile duct cancer was initially diagnosed and percutaneous transhepatic portal vein embolization was performed, preceding a planned right hepatectomy. Strictures persisted despite steroid therapy. Therefore, partial resection of the common bile duct following choledochojejunostomy was performed. Histologic examination showed diffuse and severe lymphoplasmacytic infiltration, and abundant plasma cells, which stained positive for anti-IgG4 antibody. The final diagnosis was IgG4 sclerosing cholangitis. Types 3 and 4 IgG4 sclerosing cholangitis remains a challenge to differentiate from cholangiocarcinoma. A histopathologic diagnosis obtained with a less invasive approach avoided unnecessary hepatectomy.