Hepatocellular Carcinoma: Histologic Subtypes

Other Primary Epithelial Neoplasms of the Liver

Primary liver carcinoma (PLC) is the sixth most common malignancy worldwide and the third leading cause of cancer-related mortalities. Hepatocellular carcinoma (HCC) is the most prevalent form of PLC, followed by intrahepatic cholangiocarcinoma (iCCA). In addition, there is a group of rarer PLCs that do not fit neatly into the HCC or iCCA categories. This review explores this heterogeneous group, including combined hepatocellular-cholangiocarcinoma (cHCC-CCA), intermediate cell carcinoma (ICC), mixed hepatocellular-neuroendocrine carcinoma, and undifferentiated primary liver carcinoma. cHCC-CCA is a rare subtype of PLC, characterized by both hepatocytic and cholangiocytic differentiation within the same tumor. The latest WHO classification (2019, fifth edition) redefined cHCC-CCA by eliminating the "stem cell subtypes" and emphasized that diagnosis should primarily rely on morphologic features, supported by immunohistochemical staining to better define subtypes. Intermediate cell carcinoma is a subtype of cHCC-CCA and is comprised of monomorphic tumor cells that exhibit characteristics intermediate between hepatocytes and cholangiocytes, with immunohistochemical expression of hepatocytic and cholangiocytic markers within the same cell. Another rare entity, combined HCC and neuroendocrine carcinoma (NEC), contains an admixture of HCC and NEC components within the same tumor. Undifferentiated primary liver carcinoma, on the other hand, lacks definitive lineage differentiation beyond an epithelial phenotype. These heterogeneous PLCs pose diagnostic challenges owing to their mixed/unusual histologic features and overlapping immunohistochemical markers. They tend to have poor prognoses, highlighting the critical importance of accurate and timely diagnosis.

Hepatocellular carcinoma: Morphological spectrum and subtyping as per the World Health Organization classification on FNA biopsy with cell block samples

BACKGROUND

Hepatocellular carcinoma (HCC) may be diagnosed and further subclassified in surgical specimen as per the recent World Health Organization (WHO) classification into several distinct subtypes with prognostic implications. The aim of this study was to apply this WHO classification on fine-needle aspiration biopsy (FNAB) samples of HCC and describe their features.

METHODS

This was a retrospective analysis of all ultrasound-guided FNAB of liver mass lesions in patients with suspected HCC (n = 164) over a 7-year period. Detailed morphological assessment of cytopathological features and grading was done and correlated with each other. HCC was subtyped further in cases with available cell blocks (n = 126).

RESULTS

A total of 164 cases of HCC were evaluated on FNAB with age range of 18-88 years (mean, 60 years), and with 140 (85.4%) male and 24 (14.6%) female patients. Grading performed on 160 cases of HCC (after excluding fibrolamellar HCC) revealed 23 well differentiated, 127 moderately differentiated, and 10 poorly differentiated HCCs. Subtyping was feasible in 126 cases, of which 26 cases (20.6%) showed specific subtypes that were steatohepatitic (8), lymphocyte-rich (8), fibrolamellar (4), neutrophil-rich (3), macrotrabecular massive (2), and clear cell HCC (1) with remaining cases (100) being conventional HCC, no special type.

CONCLUSION

The study demonstrates the feasibility of subtyping HCC (as per the current WHO classification) for the first time on FNAB with cell blocks that carries implication for prognostication and emphasizes the importance of obtaining tissue diagnosis by FNAB with cell blocks.

Surgical management of liver tumors

Two percent of pediatric malignancies arise primarily in the liver; roughly 60% of these cancers are hepatoblastoma (HB). Despite the rarity of these cases, international collaborative efforts have led to the consistent histological classification and staging systems, which facilitate ongoing clinical trials. Other primary liver malignancies seen in children include hepatocellular carcinoma (HCC) with or without underlying liver disease, fibrolamellar carcinoma (FLC), undifferentiated embryonal sarcoma of the liver (UESL), and hepatocellular neoplasm not otherwise specified (HCN-NOS). This review describes principles of surgical management of malignant pediatric primary liver tumors, within the context of comprehensive multidisciplinary care.

Clinicopathological Study on Morphological Subtypes of Hepatocellular Carcinoma: A Single Tertiary Referral Center Experience

AIM

We aimed to analyze hepatocellular carcinoma (HCC) morphological subtypes characterized according to the WHO classification and the International Collaboration on Cancer Reporting (ICCR) recommendations, and their prognostic features in a Dutch population.

METHODS AND RESULTS

This retrospective study in a tertiary referral center included the histopathological revision of 62 HCC resection specimens, obtained from 22 female and 40 male patients (median age: 67 years), in a period between 2011 and 2021 at the Maastricht University Medical Center +. Clinical data, morphological subtypes, growth pattern (GP), tumor grade, tumor extension, margins, and vascular and perineural invasion were collected. Eighteen cases were assigned a specific morphologic subtype and steatohepatic HCC was the most common in our cohort. Twenty-one tumors classified as conventional type HCC (HCC-NOS), commonly exhibiting two concurrent GPs. Twenty-three cases revealed a heterogeneous morphologic differentiation, compromising the combination of HCC-NOS with another morphologic subtype, most frequently a steatohepatitic component. Comparison of HCC-NOS and HCC with heterogeneous morphology did not show significant differences in the main clinicopathological characteristics and survival.

CONCLUSION

Although the most common morphologic subtype was steatohepatitic HCC, the majority of cases demonstrated multiple morphologic patterns. In case of HCC-NOS, heterogeneous GPs were often observed. Therefore, a histomorphological diagnosis based on a single tumor biopsy specimen may lead to incorrect classification of HCC. Sufficient tumor sampling of HCC resection specimens is required for the complete evaluation of all histomorphological features followed by correct subclassification in order to meet the clinical needs regarding prognostic relevance and patient follow-up.

Imaging and prognostic characterization of fat-containing hepatocellular carcinoma subtypes

PURPOSE

Steatohepatitic hepatocellular carcinoma (SH-HCC) is characterized by intratumoral fat with > 50% inflammatory changes. However, intratumoral fat (with or without inflammation) can also be found in not-otherwise specified HCC (NOS-HCC). We compared the imaging features and outcome of resected HCC containing fat on pathology including SH-HCC (> 50% steatohepatitic component), NOS-HCC with < 50% steatohepatitic component (SH-NOS-HCC), and fatty NOS-HCC (no steatohepatitic component).

MATERIAL AND METHODS

From September 2012 to June 2021, 94 patients underwent hepatic resection for fat-containing HCC on pathology. Imaging features and categories were assessed using LIRADS v2018. Fat quantification was performed on chemical-shift MRI. Recurrence-free and overall survival were estimated.

RESULTS

Twenty-one patients (26%) had nonalcoholic steatohepatitis (NASH). The median intra-tumoral fat fraction was 8%, with differences between SH-HCC and SH-NOS-HCC (9.5% vs. 5% p = 0.03). There was no difference in major LI-RADS features between all groups; most tumors were classified as LR-4/5. A mosaic architecture on MRI was rare (7%) in SH-HCC, a fat in mass on CT was more frequently depicted (48%) in SH-HCC. A combination of NASH with no mosaic architecture on MRI or NASH with fat in mass on CT yielded excellent specificity for diagnosing SH-HCC (97.6% and 97.7%, respectively). The median recurrence-free and overall survival were 58 and 87 months, with no difference between groups (p = 0.18 and p = 0.69).

CONCLUSION

In patients with NASH, an SH-HCC may be suspected in L4/LR-5 observations with no mosaic architecture at MRI or with fat in mass on CT. Oncological outcomes appear similar between fat-containing HCC subtypes.

Indocyanine green fluorescence patterns of hepatocellular carcinoma correlate with pathological and molecular features

BACKGROUND

Intraoperative Indocyanine Green Dye (ICG) routinely used in hepatobiliary surgery identifies different fluorescent patterns of hepatocellular carcinoma (HCC), a highly heterogeneous cancer. We aimed to correlate these patterns with gene mutations and extensive pathological features beyond the well-known tumor differentiation.

METHODS

Between February 2017 and December 2019, 21 HCC in 16 consecutive patients who underwent intraoperative ICG fluorescence imaging were included. Pathological review was performed by one pathologist blinded to fluorescence features. Random forest machine learning algorithm correlated pathological features of the tumor, peritumoral and non-tumoral liver, and gene mutations from a 28 gene-panel with rim and intra-lesion fluorescence.

RESULTS

Three HCC had negative intra-lesion and rim-like emission, 7 HCC had homogeneous pattern and 11 heterogeneous patterns in whom 3 with rim-like emission. Rim emission was associated with peritumoral vascular changes, lower differentiation and lower serum AFP level. Homogeneous intra-lesion fluorescence was associated with lower necrosis rate, thinner capsule, absence of peritumoral liver changes, and higher serum AFP level. Heterogeneous HCC without rim harbored lesser TP53 and ARID1A mutations.

CONCLUSION

Tumoral and peri-tumoral fluorescence classification of HCC yielded a possible intraoperative pathological and molecular characterization. These preliminary observations could lead to intraoperative refinement in surgical strategy.

18F-FDG PET/CT Imaging in Sarcomatoid Hepatocellular Carcinoma

Sarcomatoid hepatocellular carcinoma is a rare subtype of hepatocellular carcinoma. We present a 53-year-old man with a hepatic IV/VIII segment neoplasm whose tumor markers were all in the reference range. The neoplasm presented intense uptake of 18F-FDG and was confirmed as sarcomatoid hepatocellular carcinoma by immunohistochemistry. After 6 cycles of PD-1 treatment, no recurrence or metastasis was found by follow-up CT over 2 years. Thus, we reported a case of sarcomatoid hepatocellular carcinoma with complete remission to PD-1 treatment and provided some help for the diagnosis and treatment of sarcomatoid hepatocellular carcinoma.

CtBP1 Mediates Hypoxia-Induced Sarcomatoid Transformation in Hepatocellular Carcinoma

Background

Sarcomatoid hepatocellular carcinoma (sHCC), a highly aggressive subtype of hepatocellular carcinoma (HCC), mostly transforms from classical hepatocellular carcinoma (cHCC). The study intended to explore the role of C-terminal binding protein 1 (CtBP1) in sarcomatoid transformation of hepatocellular carcinoma.

Methods

Western blotting and/or immunohistochemistry were used to confirm the expression of CtBP1 and other proteins in HCC cells, xenografts and clinical tissue samples. CtBP1 shRNA-expressing lentivirus was used to infect HepG2 cells to construct CtBP1 knockdown cells. Cell migration was determined by scratch wound assays and Transwell assays. Immunofluorescence was used to label the a-tubulin cytoskeleton to evaluate cell morphology. HepG2 cells were inoculated subcutaneously in nude mice to construct xenografts and beneath the liver capsule to evaluate in vivo metastasis.

Results

Compared to that in the cHCC area, CtBP1 expression was significantly upregulated in the sHCC area, as shown by immunohistochemistry. HE staining showed that cells in the sHCC area were spindle-shaped, while those in the cHCC area were polygonal. Immunohistochemically, the epithelial markers pancytokeratin (CK) and E-cadherin were partially or completely lost, while the expression of the mesenchymal marker vimentin was upregulated in the sHCC area. Moreover, HepG2, an HCC cell line with high expression of CtBP1, autonomously underwent sarcomatoid transformation, showing a sarcomatoid morphology and phenotype. HIF1a expression was upregulated in epithelial cells adjacent to the sHCC area. Hypoxia upregulated CtBP1 protein expression and induced an EMT phenotype with increased migration and a spindle-shaped morphology in HepG2 cells. Knockdown of CtBP1 partially reversed the EMT phenotype induced by hypoxia. Silencing CtBP1 completely blocked the sarcomatoid transformation of subcutaneous xenografts and decreased lung metastasis in subcapsular xenografts of the liver in nude mice.

Conclusion

CtBP1 plays a key role in hypoxia-induced EMT and sarcomatoid transformation in HCC and could be a candidate target for the management of sHCC.

Significance of hepatocyte atypia in liver fine needle aspiration

Fine needle aspiration (FNA) of the liver is frequently the diagnostic procedure of choice for sampling hepatic lesions. One of the main diagnostic challenges in the interpretation of liver FNA is distinguishing dysplastic lesions and well-differentiated hepatocellular carcinoma (WD-HCC) from benign processes, as they share significant cytomorphologic overlap. Furthermore, the diagnosis of HCC often requires evaluation of stroma for invasion, which may not be present on cytology and small needle biopsy specimens. A reporting system for liver cytopathology has yet to be instituted. Without standardized and well-defined criteria for hepatocyte atypia, we recommend limiting the use of atypia in evaluation of liver FNA specimens to describe a diagnosis of exclusion, in which all known benign and neoplastic processes have been ruled out. The cytologic findings on the FNA of a liver nodule may be best reported as atypical hepatocytes in the absence of a core needle biopsy or cell block sufficient to render a definitive diagnosis of HCC.

MRI Features of Hepatic Sarcomatoid Carcinoma Different From Hepatocellular Carcinoma and Intrahepatic Cholangiocarcinoma

Introduction

Hepatic sarcomatoid carcinoma (HSC) is a rare type of liver cancer with a high malignant grade and poor prognosis. This study compared the clinical characteristics and magnetic resonance imaging (MRI) features of HSCs with those of hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC), aiming to identify valuable features for HSC diagnosis.

Methods

In total, 17 pathologically confirmed HSC cases, 50 HCC cases and 50 common ICC cases were enrolled from two hospitals. The clinical characteristics and MRI features of all cases were summarized and statistically analyzed.

Results

On the one hand, the incidence rates of elevated carbohydrate antigen (CA) 19-9 and elevated carcinoembryonic antigen (CEA) were significantly higher in the HSC cases than in the HCC cases (29.4% vs. 0%; 17.6% vs. 0%). The HSC enhancement patterns, primarily including progressive enhancement, were also significantly different from HCC cases. The incidence rates of heterogeneous signals on T2-weighted imaging and during the arterial phase were significantly higher in the HSC cases than in the HCC cases (94.1% vs. 66.0%; 100.0% vs. 72.0%). The diameter of HSCs was significantly larger than that in the HCC cases (6.12 cm vs. 4.21 cm), and the incidence rates of adjacent cholangiectasis, intrahepatic metastasis and lymph node enlargement were considerably higher in the HSC cases than in the HCC cases (52.9% vs. 6.0%; 47.1% vs. 12.0%; 41.2% vs. 2.0%). On the other hand, the incidence rate of elevated CA199 was significantly lower in the HSC cases than in the ICC cases (29.4% vs. 60.0%). The incidence rates of intratumoral necrosis and pseudocapsules were significantly higher in the HSC cases than in the HCC cases (35.3% vs. 8.0%; 47.1% vs. 12.0%). However, the incidence rates of target signs were significantly lower in the HSC cases than in the HCC cases (11.8% vs. 42.0%). In addition, there was no significant difference in the enhancement patterns between HSC cases and ICC cases.

Conclusions

HSCs were frequently seen in elderly men with clinical symptoms and elevated CA199 levels. The MRI features, including large size, obvious heterogeneity, hemorrhage, progressive enhancement, pseudocapsule and lymph node enlargement, contributed to the diagnosis of HSC.

Application of Immunohistochemistry in the Pathological Diagnosis of Liver Tumors

Although radiological diagnostics have been progressing, pathological diagnosis remains the most reliable method for diagnosing liver tumors. In some cases, definite pathological diagnosis cannot be obtained by histological evaluation alone, especially when the sample is a small biopsy; in such cases, immunohistochemical staining is very useful. Immunohistochemistry is the most frequently used technique for molecular pathological diagnosis due to its broad application, ease of performance and evaluation, and reasonable cost. The results occasionally reflect specific genetic mutations. The immunohistochemical markers of hepatocellular carcinoma include those of hepatocellular differentiation—such as hepatocyte paraffin 1 and arginase-1—and those of malignant hepatocytes—such as glypican-3, heat shock protein 70, and glutamine synthetase (GS). To classify the subtypes of hepatocellular adenoma, examination of several immunohistochemical markers, such as liver fatty acid-binding protein, GS, and serum amyloid A, is indispensable. Immunohistochemical staining for GS is also important for the diagnosis of focal nodular hyperplasia. The representative immunohistochemical markers of intrahepatic cholangiocarcinoma include cytokeratin (CK) 7 and CK19. In this article, we provide an overview of the application of immunohistochemistry in the pathological diagnosis of liver tumors referring to the association with genetic alterations. Furthermore, we aimed to explain the practical points in the differential diagnosis of liver tumors by immunohistochemical staining.

Clinicopathological Features of Two Extremely Rare Hepatocellular Carcinoma Variants: a Brief Review of Fibrolamellar and Scirrhous Hepatocellular Carcinoma

PURPOSE

We aimed to distinguish between fibrolamellar hepatocellular carcinoma and scirrhous hepatocellular carcinoma histopathologically.

METHODS AND RESULTS

In this review, fibrolamellar hepatocellular carcinoma and scirrhous hepatocellular carcinoma two specific and rare variants of hepatocellular carcinoma, which are difficult to diagnose histopathologically are discussed.

CONCLUSION

The clinical, radiological, gross, histopathological, immunohistochemical, and molecular features of these two tumors, which are defined by the World Health Organization (WHO), are mentioned.

Clinical manifestations and outcomes of patients with scirrhous hepatocellular carcinoma

BACKGROUND

The scirrhous hepatocellular carcinoma (HCC) is a rare subtype characterized by prominent fibrous stroma separating nests of tumor cells histologically. The clinical characteristics of scirrhous HCC have not been clearly elucidated due to limited literatures. We aimed to investigate the clinical manifestations and outcomes of patients with scirrhous HCC.

METHODS

A total of 4012 patients with histologically proven HCC from the Cancer Registry Database (2004-2016) of the National Taiwan University Hospital (NTUH) were enrolled; whereas, 30 patients with scirrhous HCC were identified from the pathology database of NTUH. We matched 120 patients with non-scirrhous HCC through propensity score according to sex, age, Barcelona Clinic Liver Cancer stage and initial treatment modality for comparison.

RESULTS

No significant difference in baseline characteristics and presentations was observed between the patients with scirrhous and non-scirrhous HCC except baseline alpha-fetoprotein level. The overall survival was comparable in these two groups. For the patients undergoing curative therapy, the risk of recurrence in the patients with scirrhous HCC was significantly higher within 24 months after curative therapy (hazard ratio [HR], 2.88, 95% confidence interval [CI], 1.43-5.80, p value, 0.003) as compared with those with non-scirrhous HCC. The overall recurrence rate was comparable in these two groups.

CONCLUSIONS

Using propensity score matching, the risk of recurrence in the patients with scirrhous HCC was significantly higher in the first 2 years after curative therapy as compared to those with non-scirrhous HCC. An individualized post-curative treatment monitoring strategy should be considered for the patients with scirrhous HCC.

Fibronodular hepatocellular carcinoma-a new variant of liver cancer: clinical, pathological and radiological correlation

AIMS

To establish and define a new, not previously reported hepatocellular carcinoma (HCC) variant, termed fibronodular HCC (FN-HCC).

METHODS

We retrospectively reviewed 290 HCC cases and identified 29 FN-HCC and 24 scirrhous HCC (SCHCC). Clinical, pathological and radiological features of FN-HCC were reviewed and compared with 30 conventional HCCs (CV-HCC) and SC-HCC.

RESULTS

FN-HCCs were more likely to arise in non-advanced fibrotic livers with lower advanced Barcelona Clinic Liver Cancer (BCLC) stage, had lower rates of progression and longer time to progression and were more likely to be surgically resected compared with CV-HCCs and SC-HCCs. Imaging analysis of FN-HCCs demonstrated higher rates of non-peripheral washout and a new distinct pattern of enhancement which is characterised by the presence of multiple rounded nodules within a lesion embedded in fibrotic-appearing parenchyma.

CONCLUSIONS

FN-HCC may represent a specific variant of HCC with distinct pathological, radiological and clinical features with potential ramifications for outcome.

The Epidemiology, Staging and Outcomes of Sarcomatoid Hepatocellular Carcinoma: A SEER Population Analysis

BACKGROUND

Hepatocellular carcinoma (HCC) subtypes differ in terms of histopathology and prognosis. Sarcomatoid HCC is rare and literature concerning the survival of patients with sarcomatoid HCC is scarce.

MATERIALS AND METHODS

Data of patients with sarcomatoid HCC, diagnosed from 1989 to 2016, were extracted from the Surveillance, Epidemiology and End Results (SEER) database. We evaluated the baseline and tumor related data, overall survival (OS), disease-specific survival and the performance (Harrell's concordance index - OS c-index) of the eighth edition of the American Joint Committee on Cancer TNM staging system (AJCC8). In addition, univariate and multivariate forward stepwise cox regression analyses were performed to identify factors associated with increased risk of death.

RESULTS

The SEER cohort consisted of 71 patients, mostly males (n=49, 69.0%), of White race (n=51, 71.8%) and the most common stage at presentation was stage IVB (n=30, 42.3%). The overall predictive ability of AJCC8 was mediocre, with an OS c-index=0.577 (SE=0.048). Surgery (hazard ratio=0.25, p<0.001) was significantly associated with reduced risk of death. Advanced TNM stage was not associated with increased risk of death.

CONCLUSION

Sarcomatoid HCC, a rare subtype of HCC, is associated with poor outcomes in terms of overall and disease-specific survival across all disease stages. Surgery seems to be of utmost importance. The eighth edition of the AJCC8 for HCC underperforms in predicting the survival of patients with sarcomatoid subtype.

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.

A rare histologic subtype of hepatocellular carcinoma, sarcomatoid hepatocellular carcinoma: report of a case

Worldwide, primary liver cancer is the fourth leading cause of cancer mortality. Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer. Sarcomatoid hepatocellular carcinoma (SHC) is a rare subtype of HCC with conventional HCC admixed with areas with sarcomatoid morphology. SHC is an aggressive, rapidly growing tumor with unfavorable prognosis. Pedunculated SHC is an uncommon presentation of SHC. Due to its rarity, much remains unknown about the etiopathogenesis, molecular underpinnings, and treatment of SHC. We present a case of an exophytic SHC arising in a background of cirrhosis in an older adult. A resection was performed, but the patient subsequently developed multiple additional intrahepatic metastatic lesions necessitating further treatment with chemotherapy.

Achievement of complete response to nivolumab in a patient with advanced sarcomatoid hepatocellular carcinoma: A case report

BACKGROUND

Sarcomatoid hepatocellular carcinoma (SHC) is a rare subtype of hepatocellular carcinoma (HCC), with a high recurrence rate after surgery. In addition to limited effective treatment for the advanced stage of SHC, the prognosis of patients with this malignancy is worse than that of patients with conventional HCC.

CASE SUMMARY

We present the case of a 54-year-old man with SHC who underwent radical segmental hepatectomy, which relapsed 4 mo after surgery due to lymphatic metastasis in the porta hepatis. Although a second surgery was performed, new metastasis developed in the mediastinal lymph nodes. Therefore, sorafenib and lenvatinib were sequentially administered as first- and second-line systemic therapies, respectively. However, progressive disease was confirmed based on a recurrent hepatic lesion and new metastatic lesion in the abdominal cavity. Percutaneous transhepatic cholangial drainage was performed to alleviate the biliary obstruction. Because the tumor was strongly positive for programmed death-ligand 1, the patient was started on nivolumab. Imaging studies revealed that after two cycles of immunotherapy, the metastatic lesions decreased to undetectable levels.

CONCLUSION

The patient experienced continuous complete remission for 8 mo. Immune checkpoint inhibitors are useful for the treatment of advanced SHC.

Atypical Appearance of Hepatocellular Carcinoma and Its Mimickers: How to Solve Challenging Cases Using Gadoxetic Acid-Enhanced Liver Magnetic Resonance Imaging

Hepatocellular carcinoma (HCC) can be diagnosed noninvasively with contrast-enhanced dynamic computed tomography, magnetic resonance imaging, or ultrasonography on the basis of its hallmark imaging features of arterial phase hyperenhancement and washout on portal or delayed phase images. However, approximately 40% of HCCs show atypical imaging features, posing a significant diagnostic challenge for radiologists. Another challenge for radiologists in clinical practice is the presentation of many HCC mimickers such as intrahepatic cholangiocarcinoma, combined HCC-cholangiocarcinoma, arterioportal shunt, and hemangioma in the cirrhotic liver. The differentiation of HCCs from these mimickers on preoperative imaging studies is of critical importance. Hence, we will review the typical and atypical imaging features of HCCs and the imaging features of its common mimickers. In addition, we will discuss how to solve these challenges in practice.

Outcomes of Patients with Scirrhous Hepatocellular Carcinoma: Insights from the National Cancer Database

INTRODUCTION

Scirrhous hepatocellular carcinoma (HCC) is a rare primary liver tumor characterized by extensive fibrosis and production of parathyroid hormone-related peptide. There have been conflicting reports on patient survival in scirrhous versus non-scirrhous HCC. The objective of the present study was to define the clinical features, practice patterns, and long-term outcomes of patients with scirrhous HCC versus non-scirrhous HCC in a propensity score-matched cohort.

METHODS

A propensity score-matched cohort was created using data from the National Cancer Database for 2004 to 2015. A multivariable Cox proportional hazards regression analysis was performed to assess the effect of the scirrhous HCC variant on overall survival.

RESULTS

Among the 70,426 patients with a diagnosis of HCC who met the inclusion criteria, 99.8% had non-scirrhous HCC (n = 70,290) whereas a small subset had scirrhous HCC (n = 136, 0.19%). While 20,330 (28.9%) patients underwent liver-directed therapy (resection, ablation, and transplantation), the majority did not (n = 50,096, 71.1%). After propensity matching, there were no difference in 1-, 3-, or 5-year overall survival among patients with scirrhous versus non-scirrhous HCC (1-year overall survival (OS), 53.7% versus 51.0%; 3-year OS, 34.6% versus 28.7%; and 5-year OS, 18.0% versus 21.0%, respectively; p = 0.52). While the scirrhous HCC variant was not associated with survival (hazard ratio [HR] 0.93, 95% CI 0.74-1.16), non-receipt of liver-directed therapy (HR 0.24, 95% CI 0.18-0.32), advanced AJCC stage (III/IV) (HR 2.14, 95% CI 1.55-2.95), and non-academic facilities (HR 0.60, 95% CI 0.49-0.73) remained associated with worse survival.

CONCLUSION

Patients with the scirrhous variant had a comparable overall survival compared with individuals who had non-scirrhous HCC. Failure to receive liver-directed therapy, advanced AJCC stage (III/IV), and treatment at a non-academic facility was strongly associated with a worse long-term prognosis.

Infiltrative non-mass-like hepatocellular carcinoma initially presenting with isolated malignant portal vein thrombosis: A case report and review of the literature

Hepatocellular carcinoma (HCC) shows a rising incidence and mortality rates worldwide. HCC is divided into several distinct subtypes, both morphologically and histopathologically. Among these subtypes, infiltrative HCC may be the most challenging subtype to diagnose, given its characteristic myriad of tumor nodules blended with normal hepatocytes without a distinct mass-like lesion. Herein, we report an unusual case of an infiltrative HCC initially presenting with isolated malignant portal vein thrombosis and provide a brief review of the literature regarding the infiltrative HCC subtype. Additionally, we demonstrate how sonoelastography could aid in detecting the appropriate biopsy area in the infiltrative HCC subtype. To our knowledge, there have not been previously reported cases describing the use of sonoelastography in the evaluation of the appropriate area for the targeted liver biopsy.

Management and outcomes among patients with sarcomatoid hepatocellular carcinoma: A population-based analysis

BACKGROUND

Few data are available regarding the management and outcomes among patients with sarcomatoid hepatocellular carcinoma (HCC) due to its rarity.

METHODS

Patients diagnosed with sarcomatoid HCC from 2004 through 2015 were identified in the National Cancer Data Base. Overall survival (OS) was calculated among patients with sarcomatoid versus conventional HCC using a 1:3 propensity score matching based on sex, age, and American Joint Committee on Cancer (AJCC) stage of disease.

RESULTS

The final analytic cohort included 104 patients with sarcomatoid HCC and 312 patients with conventional HCC. Patients with sarcomatoid HCC more often had a larger median tumor size (8.5 cm vs 5.4 cm; P < .001) and poorly or undifferentiated tumors (52.9% vs 13.8%; P < .001) compared with patients who had conventional HCC. 5-year OS was worse among patients with sarcomatoid versus conventional HCC (5.7% vs 30.1%; P < .001). Subgroup analysis demonstrated worse 5-year OS among patients with sarcomatoid versus conventional HCC among patients treated with either curative-intent or palliative therapies. Stage-specific subgroup analysis indicated a worse OS among patients with AJCC stage I, stage II, or stage III sarcomatoid HCC. On multivariable analysis, uninsured status, advanced AJCC stage (stage III/stage IV), and histological sarcomatoid subtype were independently associated with worse outcomes (all P < .05).

CONCLUSIONS

Sarcomatoid HCC is a very rare variant of HCC, which was associated with larger tumor size and worse tumor grade on presentation. On propensity score matched analyses that controlled for known confounding factors, patients with sarcomatoid HCC had a worse stage-for-stage long-term survival compared with patients who had conventional HCC.

Macrotrabecular Hepatocellular Carcinoma: An Aggressive Subtype of Hepatocellular Carcinoma

The macrotrabecular (MT) pattern of hepatocellular carcinoma (HCC) has been suggested to represent a distinct HCC subtype. We retrospectively reviewed 231 HCC cases. Detailed pathologic evaluation for histologic patterns, including MT-pattern, was performed for each case and recorded as percentage involved at 10% intervals. MT-pattern was defined as having trabeculae >6 cells thick. After excluding all recognized HCC subtypes, remaining cases were deemed conventional HCC (CV-HCC) and served as controls. HCCs with a component of ≥10%, ≥30% and ≥50% MT-pattern were identified in 41 (17.7%), 24 (10.4%) and 4 (1.7%) cases, respectively. The clinicopathologic features of HCCs with 10% to 29% MT-pattern (n=17, 7.4%) were largely similar to CV-HCC. No significant difference was observed between the 30% and 49% (n=20) and ≥50% (n=4) MT groups, hence these were combined for further analysis as MT-HCC. MT-HCCs (≥30% MT-pattern) were larger tumors (5.5 vs. 3.1 cm), were less likely to be associated with cirrhosis (54% vs. 79%), were more likely to have hepatitis B (21% vs. 5%) and less likely hepatitis C infection (33% vs. 58%) compared with CV-HCC. MT-HCC was associated with the presence of anaplastic tumor cells (42% vs. 14%), higher alpha-fetoprotein level, higher AJCC stage, and higher histologic grade. Compared with patients with CV-HCC, patients with MT-HCC had poorer overall survival. Patients with MT-HCC who underwent primary resection or transplantation had a higher recurrence rate and worse recurrence-free survival. Our findings suggest that ≥30% MT-pattern could be used as the more appropriate cut-off for defining MT-HCC, which represents a unique and aggressive HCC histologic subtype.

Paraneoplastic leukemoid reaction in a patient with sarcomatoid hepatocellular carcinoma: A case report

BACKGROUND

Sarcomatoid hepatocellular carcinoma (SHC) combined with paraneoplastic leukemoid reaction (PLR), which is associated with a poor prognosis, is rarely seen in the clinic. Here, we report the case of a patient in the above situation.

CASE SUMMARY

A 75-year-old female patient with a past medical history of hypertension and cerebral infarction paid a hospital visit as a result of right upper quadrant abdominal pain and anorexia for two months. Laboratory examination revealed a white blood cell (WBC) count of 43790/μL, which was then increased up to 77050/μL. In addition, the results of bone marrow examination suggested a leukemoid reaction. Computed tomography (CT) revealed a focal hepatic mass, which was confirmed through pathological examination to be an SHC postoperatively. In addition, the WBC count had fallen to a normal level before she left the hospital. However, the patient died two and a half months after the second hospital admission.

CONCLUSION

This is a rare case of SHC combined with PLR, both of which have an extremely poor prognosis.

Clinical Manifestations and Outcomes of Patients with Sarcomatoid Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer and the second leading cause of cancer-related deaths worldwide. Sarcomatoid HCC is a rare histological subtype of HCC with largely unclear clinical manifestations and outcomes. We evaluated the clinical manifestations and outcomes of patients with sarcomatoid HCC. We identified 5,047 patients with histologically proven HCC from the Cancer Registry Database (1996-2016) of National Taiwan University Hospital. Among them, 40 patients with sarcomatoid HCC were identified from the pathology database of National Taiwan University Hospital. We included 160 patients with nonsarcomatoid HCC through propensity score matching according to sex, age, and Barcelona Clinic Liver Cancer stage. The majority of these patients with sarcomatoid HCC were men (75%); their median age was 58 years. Only 47.5% of the patients with sarcomatoid HCC presented with typical image patterns of HCC. The pathological grading of sarcomatoid HCC was more advanced compared with that of nonsarcomatoid HCC (42.5% vs. 23.8% in grade III and IV, P < 0.0001). The sarcomatoid group had significantly shorter median recurrence-free (13.3 vs. 84.2 months, log-rank P < 0.0001) and overall (8.3 vs. 69.3 months, log-rank P < 0.0001) survival than did the nonsarcomatoid group. The results of the multivariable Cox proportional hazard model revealed histological sarcomatoid subtype as an independent factor for all-cause mortality (hazard ratio [HR], 6.47; 95% confidence interval [CI], 3.12-13.43; P < 0.0001) and tumor recurrence (HR, 4.08; 95% CI, 1.72-9.66; P = 0.001). Conclusion: Compared with nonsarcomatoid HCC, sarcomatoid HCC was associated with more advanced histological grades and atypical image patterns. Histological sarcomatoid subtype is an independent predictor of tumor recurrence after curative treatment and all-cause mortality in patients with HCC.

A practical diagnostic approach to hepatic masses

The differential diagnosis of hepatic mass lesions is broad and arriving at the right diagnosis can be challenging, especially on needle biopsies. The differential diagnosis of liver tumors in children is different from adults and is beyond the scope of this review. In adults, the approach varies depending on the age, gender, and presence of background liver disease. The lesions can be divided broadly into primary and metastatic (secondary), and the primary lesions can be further divided into those of hepatocellular origin and nonhepatocellular origin. The first category consists of benign and malignant lesions arising from hepatocytes, while the second category includes biliary, mesenchymal, hematopoietic, and vascular tumors. Discussion of nonepithelial neoplasms is beyond the scope of this review. The hepatocytic lesions comprise dysplastic nodules, focal nodular hyperplasia, hepatic adenoma, and hepatocellular carcinoma, and the differential diagnosis can be challenging requiring clinicopathological correlation and application of immunohistochemical (IHC) markers. Liver is a common site for metastasis, sometimes presenting with an unknown primary site, and proper workup is the key to arriving at the correct diagnosis. The correct diagnosis in this setting requires a systematic approach with attention to histologic features, imaging findings, clinical presentation, and judicious use of IHC markers. The list of antibodies that can be used for this purpose keeps on growing continually. It is important for pathologists to be up to date with the sensitivity and specificity of these markers and their diagnostic role and clinical implications. The purpose of this review is to outline the differential diagnosis of hepatic masses in adults and discuss an algorithmic approach to make a right diagnosis.

Immune checkpoint blockade for the treatment of human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers with a high recurrence rate. Currently, tyrosine kinase inhibitors (TKIs) are the first-line treatment for cases refractory to conventional therapies. However, the acquisition of somatic mutations can result in TKI resistance. Clinical evidence suggests that acquired immunity contributes to the suppression of tumor recurrence, indicating the potential of induced antitumor immune reaction for the treatment of HCC. Recently, immune checkpoint inhibitors have become available for the treatment of malignancies. They are effective regardless of the response to prior therapies and a durable effect can be expected, which should be attributed to an adaptive immunity to HCC components. The results of phase I/II trials of nivolumab, an anti-programmed cell death-1 antibody, showed that 20% of patients showed objective response and that nivolumab was effective regardless of prior sorafenib treatment and viral status. Nivolumab received expedited Food and Drug Administration approval in 2017 for the treatment of advanced HCC after failure or intolerance to sorafenib. However, the majority of the patients remain refractory, likely due to the solid immune suppressive status, which involves many stromal cells, humoral mediators, and suppressive checkpoint molecules. Therefore, current clinical trials are focusing on how immunosuppressive conditions in HCC might be overcome using immune checkpoint inhibitors in combination with different types of immune checkpoint blockades, TKIs, and other conventional treatments. The development of immune checkpoint inhibitors is rapidly progressing and these inhibitors are likely to be key agents for HCC treatment in the near feature.

Supervised learning reveals circulating biomarker levels diagnostic of hepatocellular carcinoma in a clinically relevant model of non-alcoholic steatohepatitis; An OAD to NASH

Although cirrhosis is a key risk factor for the development of hepatocellular carcinoma (HCC), mounting evidence indicates that in a subset of patients presenting with non-alcoholic steatohepatitis (NASH) HCC manifests in the absence of cirrhosis. Given the sheer size of the ongoing non-alcoholic fatty liver disease (NAFLD) epidemic and the dismal prognosis associated with late-stage primary liver cancer there is an urgent need for HCC surveillance in the NASH population. Using serum levels of HCC biomarkers as vectors and biopsy-proven HCC or no HCC as outputs / binary classifier, a supervised learning campaign was undertaken to develop a minimally invasive technique for making a diagnosis of HCC in a clinically relevant model of NASH. Adult mice randomized to control diet or a fast food diet (FFD) were followed for up to 14 mo and serum level of a panel of HCC-relevant biomarkers was compared with liver biopsies at 3 and 14 mo. Both NAFLD Activity Score (NAS) and hepatic hydroxyproline content were elevated at 3 and 14 mo on FFD. Picrosirius red staining of liver sections revealed a filigree pattern of fibrillar collagen deposition with no cirrhosis at 14 mo on FFD. Nevertheless, 46% of animals bore one or more tumors on their livers confirmed as HCC in hematoxylin-eosin-stained liver sections. In this training set, receiver operating characteristic (ROC) curves analysis for serum levels of the HCC biomarkers osteopontin (OPN), alpha-fetoprotein (AFP) and Dickkopf-1 (DKK1) returned concordance-statistic/area under ROC curve of ≥ 0.89. Serum levels of OPN (threshold, 218 ng/mL; sensitivity, 82%; specificity, 86%), AFP (136 ng/mL; 91%; 97%) and DKK1 (2.4 ng/mL; 82%; 81%) diagnostic for HCC were confirmed in a test set comprising mice on control diet or FFD and mice subjected to hepatic ischemia-reperfusion injury. These data suggest that levels of circulating OPN, AFP and DKK1 can be used to make a diagnosis of HCC in a clinically relevant model of NASH.

Immunohistochemistry in the Diagnosis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) can be difficult to distinguish from its mimics, including metastatic tumor, benign hepatocellular lesion, and high-grade dysplastic nodule, especially when limited biopsy material is available. Hence, the judicious use of immunohistochemical stains is necessary to establish a correct diagnosis. This article describes advantages and disadvantages of immunohistochemical markers that are most commonly used to distinguish between these lesions. Diagnostic workup of malignant liver mass (HCC and its histologic variants vs metastatic tumor) as well as well-differentiated hepatocellular lesion (well-differentiated HCC vs focal nodular hyperplasia vs hepatocellular adenoma) is also discussed.

Immunohistochemical approach for the diagnosis of a liver mass on small biopsy specimens

Well-differentiated hepatocellular carcinoma (HCC) shares overlapping histological features with benign hepatocellular lesions, including hepatocellular adenoma and focal nodular hyperplasia in non-cirrhotic liver, and with high-grade dysplastic nodule in cirrhotic liver. Several metastatic tumors, such as neuroendocrine tumor, renal cell carcinoma, adrenocortical carcinoma, melanoma, and epithelioid angiomyolipoma, can be indistinguishable from HCC on histologic grounds. Since this distinction has important therapeutic implications, judicious use of immunohistochemical markers plays an important role in establishing an accurate diagnosis, especially when limited material of tumor is available on cell block or a small core biopsy. This review describes commonly used immunohistochemical markers used in the diagnosis of HCC, highlighting advantages and disadvantages of each marker, and suggests appropriate immunohistochemical panels for specific clinicopathologic situations.