Morphologic studies of the liver cell dysplasia

Current Concepts of Precancerous Lesions of Hepatocellular Carcinoma: Recent Progress in Diagnosis

The most common cause of hepatocellular carcinoma (HCC) is chronic hepatitis and cirrhosis. It is proposed that precancerous lesions of HCC include all stages of the disease, from dysplastic foci (DF), and dysplastic nodule (DN), to early HCC (eHCC) and progressed HCC (pHCC), which is a complex multi-step process. Accurately identifying precancerous hepatocellular lesions can significantly impact the early detection and treatment of HCC. The changes in high-grade dysplastic nodules (HGDN) were similar to those seen in HCC, and the risk of malignant transformation significantly increased. Nevertheless, it is challenging to diagnose precancerous lesions of HCC. We integrated the literature and combined imaging, pathology, laboratory, and other relevant examinations to improve the accuracy of the diagnosis of precancerous lesions.

Technical Note Cell Dysplasia - Cell Dysplastic Features (A Morphological Note)

Cell dysplasia is a currently used term describing various cellular developmental abnormalities visible by microscopy. However, detailed description of these developmental abnormalities might provide useful information not only on the cell state but also on the abnormal developmental steps of cell lineages, tissues and organs. The frequently noted visualized cell dysplastic features reflect nuclear- or nucleolar-cytoplasmic anarchy (asynchrony), premature heterochromatin condensation state, marked aneuploidy, abnormal nucleus-cytoplasm ratio, abnormality of cell organelles including mitochondria, abnormal presence or absence of cell lineage-specific granules, and formation of peripheral buds or blebbing on the cell surface. The description of these frequently occurring cell dysplastic features might also be helpful in recognizing and studying defined specific disorders of the "whole macro-body" expressed as a disease.

The proliferation of atypical hepatocytes and CDT1 expression in noncancerous tissue are associated with the postoperative recurrence of hepatocellular carcinoma

Recently, we reported that extent of proliferation of atypical hepatocytes (atypical hepatocytes) was most important histological risk factor for development of hepatocellular carcinoma (HCC) from chronic hepatitis C or liver cirrhosis. Here, we aimed to clarify whether the atypical hepatocytes in noncancerous sections is also involved in postoperative recurrence. Furthermore, we investigated significant genes involved in the atypical hepatocytes. Association between the extent of atypical hepatocytes in noncancerous tissue and postoperative recurrence was validated in 356 patients with HCC. Next, we identified putative signature genes involved in extent of atypical hepatocytes. First, atypical hepatocytes or hepatocytes other than the atypical hepatocyte in noncancerous sections of 4 HCC patients were selectively collected by laser capture microdissection (LCM). Second, the gene expression profiles of the selected hepatocyte populations were compared using Ion AmpliSeq Transcriptome Human Gene Expression Kit (Thermo Fisher SCIENTIFIC, Waltham, MA, USA) analysis. Finally, we validated the mRNA expression of the extracted genes in noncancerous frozen liver tissue from 62 patients with HCC by RT-qPCR to identify the signature genes involved in both the extent of atypical hepatocytes and postoperative recurrence. Furthermore, the extent of atypical hepatocytes and CDT1 expression in noncancerous sections from 8 patients with HCC were also validated by selectively collecting samples using LCM. The extent of atypical hepatocytes was associated with postoperative recurrence. Of the genes that showed significant differences in expression levels between two populations, the expression of the chromatin licensing and DNA replication factor 1 (CDT1) gene was most strongly associated with the extent of atypical hepatocytes and was also associated with postoperative recurrence. Furthermore, CDT1-positive cells that exhibited stronger expression resembled those morphologically considered to be atypical hepatocytes. CDT1 and Ki-67 were colocalized in the nuclei of both hepatocytes and cancer cells. The hepatocytes in noncancerous livers were not uniform in each hepatocyte population, suggesting that the accumulation of genetic abnormalities was variable. We found that the strong degree of atypical hepatocytes and high CDT1 mRNA expression represent a high carcinogenic state of the liver. Thus, we consider the evaluation of degree of these could support the personalized medicine.

Etiology, Pathogenesis, Diagnosis, and Practical Implications of Hepatocellular Neoplasms

Hepatocellular carcinoma (HCC), a major global contributor of cancer death, usually arises in a background of chronic liver disease, as a result of molecular changes that deregulate important signal transduction pathways. Recent studies have shown that certain molecular changes of hepatocarcinogenesis are associated with clinicopathologic features and prognosis, suggesting that subclassification of HCC is practically useful. On the other hand, subclassification of hepatocellular adenomas (HCAs), a heterogenous group of neoplasms, has been well established on the basis of genotype–phenotype correlations. Histologic examination, aided by immunohistochemistry, is the gold standard for the diagnosis and subclassification of HCA and HCC, while clinicopathologic correlation is essential for best patient management. Advances in clinico-radio-pathologic correlation have introduced a new approach for the diagnostic assessment of lesions arising in advanced chronic liver disease by imaging (LI-RADS). The rapid expansion of knowledge concerning the molecular pathogenesis of HCC is now starting to produce new therapeutic approaches through precision oncology. This review summarizes the etiology and pathogenesis of HCA and HCC, provides practical information for their histologic diagnosis (including an algorithmic approach), and addresses a variety of frequently asked questions regarding the diagnosis and practical implications of these neoplasms.

Controversies in the Management of Hepatitis B: Hepatocellular Carcinoma

Hepatitis B is the leading cause of hepatocellular cancer (HCC) worldwide. Untreated, annual HCC incidence rates in chronic hepatitis B subjects are 0.4% in noncirrhotics and 2% to 3% in cirrhotics. Surveillance with ultrasound with/without α-fetoprotein at 6-month intervals is recommended in at-risk persons including children. Antiviral therapy in chronic hepatitis B with entecavir or tenofovir significantly lowers the risk of HCC across all stages of liver disease, and lowers the risk of HCC recurrence following curative therapy. There are insufficient data to recommend use of tenofovir over entecavir in the prevention of de novo or recurrent HCC postcurative therapy.

Hepatocarcinogenesis: Radiology-Pathology Correlation

In the background of chronic liver disease, hepatocellular carcinoma develops via a complex, multistep process called hepatocarcinogenesis. This article reviews the causes contributing to the process. Emphasis is made on the imaging manifestations of the pathologic changes seen at many stages of hepatocarcinogenesis, from regenerative nodules to dysplastic nodules and then to hepatocellular carcinoma.

Pathological predictive factors for late recurrence of hepatocellular carcinoma in chronic liver disease

BACKGROUND & AIMS

Late recurrence of hepatocellular carcinoma (HCC) is regarded as de novo HCC from chronic hepatitis. This study investigated clinicopathological and molecular factors to develop a nomogram for predicting late HCC recurrence (>2 years after curative resection).

METHODS

The training and validation cohorts included HCC patients with a major aetiology of hepatitis B who underwent curative resection. Clinicopathological features including lobular and porto-periportal inflammatory activity, fibrosis and liver cell change were evaluated. Proteins encoded by genes related to late recurrence were identified using a reverse phase protein array of 95 non-tumourous liver tissues. Immunoexpression of phosphorylated signal transducer and activator of transcription 3 (pSTAT3), plasminogen activator inhibitor-1, phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2) and spleen tyrosine kinase (SYK) was measured.

RESULTS

Late recurrence occurred in 74/402 (18%) and 47/243 (19%) in the training and validation cohorts respectively. Cirrhosis, moderate/severe lobular inflammatory activity, and expression of pSTAT3, pERK1/2, and SYK proteins correlated to the gene signature of hepatocyte injury and regeneration were independently associated with late recurrence, with odds ratios (95% confidence intervals) of 2.0 (1.2-3.3), 21.1 (4.3-102.7) and 6.0 (2.1-17.7) respectively (P < .05 for all). A nomogram based on these variables (histological parameters and immunohistochemical marker combinations) showed high reliability in both the training and validation cohorts (Harrell's C index: 0.701 and 0.716; 95% confidence intervals: 0.64-0.76 and 0.64-0.79 respectively).

CONCLUSIONS

The combination of pSTAT3, pERK1/2 and SYK immunoexpression with high lobular inflammatory activity and cirrhosis (fibrosis) predicts late HCC recurrence.

[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.

Detecting qualitative changes in biological systems

Currently, most diseases are diagnosed only after significant disease-associated transformations have taken place. Here, we propose an approach able to identify when systemic qualitative changes in biological systems happen, thus opening the possibility for therapeutic interventions before the occurrence of symptoms. The proposed method exploits knowledge from biological networks and longitudinal data using a system impact analysis. The method is validated on eight biological phenomena, three synthetic datasets and five real datasets, for seven organisms. Most importantly, the method accurately detected the transition from the control stage (benign) to the early stage of hepatocellular carcinoma on an eight-stage disease dataset.

Pathobiological and Radiological Approach For Hepatocellular Carcinoma Subclassification

Many advances have been made in the imaging diagnosis and in the histopathological evaluation of HCC. However, the classic imaging and histopathological features of HCC are still inadequate to define patient’s prognosis. We aimed to find the link between new proposed morphovascular patterns of hepatocellular carcinoma (HCC) and magnetic resonance imaging (MRI) features to identify pre-operatory markers of biologically aggressive HCC. Thirty-nine liver nodules in 22 patients were consecutively identified. Histopathological analysis and immunohistochemistry for CD34 and Nestin were performed to identify the four different HCC morphovascular patterns. MRI was performed using gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid. Three out of four morphovascular HCC patterns showed peculiar MRI features: in particular Pattern D (solid aggressive HCCs with CD34+/Nestin+ new-formed arteries) were isointense on T1-WI in 83% of cases and hyperintense on T2-WI in 50%. Five histologically-diagnosed HCC were diagnosed as non-malignant nodules on MRI due to their early vascularization and low aggressiveness (Pattern A). The comparison between histology and MRI confirms that a subclassification of HCC is possible in a pre-operatory setting. MRI seems to reinforce once more the identity of the different morphovascular HCC patterns and the possibility to pre-operatively identify HCCs with features of biological aggressiveness.

Intravoxel Incoherent Motion Diffusion-Weighted Imaging for Evaluation of the Cell Density and Angiogenesis of Cirrhosis-Related Nodules in an Experimental Rat Model: Comparison and Correlation With Dynamic Contrast-Enhanced MRI

Background

Intravoxel incoherent motion diffusion‐weighted imaging (IVIM‐DWI) and dynamic contrast‐enhanced MRI (DCE‐MRI) are sensitive imaging modalities for detecting liver lesions, but their value in evaluating cirrhosis‐related nodules remains unclear.

Purpose

To investigate whether IVIM‐DWI and DCE‐MRI can differentiate different types of cirrhosis‐related nodules, and whether these modalities can monitor changes in cell density and angiogenesis during the malignant transformation of cirrhosis‐related nodules in a rat model

Study Type

Prospective.

Animal Model

Thirty‐five male Sprague–Dawley rats with 106 cirrhosis‐related nodules (19 regenerative nodules [RNs], 47 dysplastic nodules [DNs], and 40 hepatocellular carcinomas [HCCs]).

Field Strength/Sequence

IVIM‐DWI and DCE sequence at 3.0T MRI.

Assessment

IVIM‐DWI parameters (D, D*, f, and apparent diffusion coefficient [ADC]) and DCE‐MRI parameters (K^trans, K_ep, and V_e) were calculated by two radiologists using postprocessing software. The “cell density” and “unpaired arterial ratio” were analyzed with a microscope by two pathologists.

Statistical Tests

MRI parameters were compared among the different types of nodules by one‐way analysis of variance or the Kruskal–Wallis test. The Pearson correlation test was used to analyze the correlation of MRI parameters with the pathological types of nodules, cell density, and unpaired arterial ratio.

Results

The K^trans, K_ep, and V_e values of HCCs were significantly higher than those of DNs and RNs. D and ADC values were significantly lower in HCCs than in DNs and RNs. There were moderate positive correlations of K^trans with the pathological types of nodules and the unpaired arterial ratio. Moderate negative correlations were observed among D, ADC, and the pathological types of nodules, between D and cell density, and between ADC and cell density.

Data Conclusion

IVIM‐DWI and DCE‐MRI are valuable in differentiating different types of cirrhotic‐related nodules. D and ADC are correlated with changes in cell density during the malignant transformation of cirrhosis‐related nodules, while K^trans is correlated with increased angiogenesis.

Level of Evidence: 1

Technical Efficacy: Stage 1

J. Magn. Reson. Imaging 2020;51:812–823.

Primary Liver Cancers-Part 1: Histopathology, Differential Diagnoses, and Risk Stratification

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC) are the 2 most common primary malignant liver tumors, with hepatocellular and bile ductular differentiation, respectively. This article reviews the key histopathological findings of these 2 primary liver cancers and includes a review of the role of ancillary testing for differential diagnosis, risk stratification according to the American Joint Committee on Cancer (AJCC) staging recommendation, and a review of precancerous lesions. A literature review was conducted to identify articles with information relevant to precancerous precursors, current histopathological classification, ancillary testing, and risk stratification of primary malignant liver tumors. The histomorphology of normal liver, preinvasive precursors, primary malignancies, and morphological variants, and the utilization of ancillary tests for the pathological diagnosis are described. Dysplastic nodules are the preinvasive precursors of HCC, and intraductal papillary neoplasms of bile ducts and biliary intraepithelial neoplasia are the preinvasive precursors of CC. Benign liver nodules including focal nodular hyperplasia and adenomas are included in this review, since some forms of adenomas progress to HCC and often they have to be differentiated from well-differentiated HCC. A number of morphological variants of HCC have been described in the literature, and it is necessary to be aware of them in order to render the correct diagnosis. Risk stratification is still dependent on the AJCC staging system. The diagnosis of primary liver carcinomas is usually straightforward. Application of the appropriate ancillary studies aids in the differential diagnosis of difficult cases. The understanding of the carcinogenesis of these malignancies has improved with the standardization of the pathological classification of preinvasive precursors and studies of the molecular pathogenesis. Risk stratification still depends on pathological staging.

The Liver in Tyrosinemia Type I: Clinical Management and Course in Quebec

HT1 is a severe autosomal recessive disorder due to the deficiency of fumarylacetoacetate hydrolase (FAH), the final enzyme in the degradation of tyrosine. Before the era of treatment with 2-(2-N-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC), even with newborn screening and optimal diet therapy, HT1 patients often developed liver failure. Death was common in patients who did not undergo liver transplantation. For the last two decades, NTBC has revolutionized the management of HT1 patients. In screened newborns treated within the first month of life, we have not observed hepatocarcinoma. If patients are not detected at birth by neonatal screening, the diagnosis and treatment must be performed on an emergency basis, and patients are at risk for complications. Long term adhesion to treatment and reliable early detection of hepatocellular carcinoma (HCC) are two important challenges. In this chapter, we describe the clinical, biological, histo-pathological and imaging findings of HT1 in Québec before the era of NTBC. We also describe the hepatic status of nontransplanted tyrosinemic patients in Quebec and current management practices in the Quebec NTBC Study.

Well-differentiated hepatocellular nodule: Making a diagnosis on biopsy and resection specimens of patients with advanced stage chronic liver disease

Guided liver biopsy is commonly employed to determine the identity of distinct hepatic nodules detected on imaging studies of patients with advanced stage chronic liver diseases. Discrimination among large regenerative nodule, dysplastic nodule and well-differentiated hepatocellular carcinoma is often difficult and relies on subtle histologic findings. Sampling is an important consideration in biopsy material, as compared to resection specimens, because the diagnostic features may be focal within the nodule. Immunohistochemical stains may be useful in distinguishing between large regenerative and dysplastic nodule on the one hand, versus early and classic hepatocellular carcinoma on the other. Ongoing research on the early lesions of hepatocarcinogenesis is enhancing our understanding of the sequential steps of this process and provides novel tools for histopathologic differential diagnosis.

Hepatocellular Carcinoma and Its Precursors in 103 HBV-Related Cirrhotic Explanted Livers: A Study from South Iran

BACKGROUND

The most common cause of liver transplantation in Iran is hepatitis B positive cirrhosis, and it also one of the major and important causes of hepatocellular carcinoma (HCC). Most cases with HCC follow a multistep sequence. Morphologic lesions during hepatocarcinogenesis include dysplastic lesions and small cancerous lesions (2 cm in diameter; early HCC). However, insufficient information is available on the incidence of HCC and its precursors in hepatitis B-related cirrhosis.

OBJECTIVES

In this study, we determined the incidence of HCC and its precursors in hepatitis B-related cirrhosis in the largest liver transplant center in Iran.

METHODS

In a two-year study, all explanted livers of patients with hepatitis B virus (HBV)-positive cirrhosis were completely sectioned and examined. Each specimen was investigated grossly and microscopically to determine any abnormal nodule or cellular changes (at least 15 sections from each liver).

RESULTS

Among all explanted cirrhotic livers (103 livers) during the study period (2014 - 2015), 92 (89.3%) had dysplastic foci with large cell changes (LCC), 57 (55.3%) of which showed small cell changes (SCC) as well. Thirty-nine cases (37.9%) had low-grade dysplastic nodules (LGDN), 38 (36.9%) high-grade dysplastic nodules (HGDN), 19 (18.4%) were early hepatocellular carcinoma (eHCC), and 21 (20.4%) were hepatocellular carcinoma more than 2 cm. All the cases with eHCC and HCC of more than 2 cm also had SCC, LCC, HGDN, and LGDN. Thirteen cases of eHCC were accompanied with HCCs more than 2 cm, and 6 cases of eHCC did not show any HCC (larger than 2 cm).

CONCLUSIONS

SCC, LGDN, and HGDN are common associated findings and precursors of HCC in livers infected with hepatitis B. A strict follow-up and a precise and thorough sampling of livers with SCC and any abnormal dysplastic nodules (DNs), especially those larger than 1 cm, are highly recommended because these DNs are highly associated with malignancy.

Anatomic pathology of hepatocellular carcinoma: histopathology using classic and new diagnostic tools

Hepatocellular carcinoma can be diagnosed on a needle biopsy of the liver; however, uncertainty may arise because of the inherent complexity of liver histology. This article aims to provide practicing pathologists with tools for the approach to mass-directed liver biopsies clinically concerning for hepatocellular carcinoma. The examination of routine hematoxylin-eosin stains and the use of ancillary histochemical and immunohistochemical stains are discussed. Sections reviewing liver carcinoma with biphenotypic differentiation and the challenge of dysplastic nodules are included.

Expression of glypican 3 enriches hepatocellular carcinoma development-related genes and associates with carcinogenesis in cirrhotic livers

Glypican-3 (GPC3) protein expression was determined by immunohistochemical analysis from 29 normal livers, 80 cirrhotic livers sample taken near hepatocellular carcinoma (HCC), and 87 cirrhotic livers without HCC. The levels for miR-657 and HCC-related gene mRNAs were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Also, a published microarray dataset was used for gene set enrichment analysis (GSEA) to investigate the relationship between GPC3- and HCC-related gene signatures. Kaplan-Meier analysis was used to evaluate the relationship between GPC3 and HCC recurrence. GPC3 protein expression was not detected in any of the 29 (0%) normal livers, but was detected in 32 of 87 (37%) cirrhotic livers without HCC, and 51 of 80 (64%) cirrhotic liver samples taken near HCC sites (P < 0.001). The GPC3-positive rate in cirrhotic livers of viral origin was 68% (27/40), which was significantly higher than for non-viral cirrhotic livers (11%, 5/47) (P < 0.001). Also, GPC3 expression positively correlated with mRNA expression of HCC-related genes in the qRT-PCR and GSEA evaluations. Furthermore, HCC recurrence in cirrhotic liver samples taken near HCC sites was significantly higher in the GPC3-positive group than the GPC3-negative group (Log-rank P = 0.02, HR = 3.26; 95% CI = 1.20-10.29). This study demonstrated that highly expression of GPC3 could enrich HCC-related genes' mRNA expression and positive associate with dysplasia in cirrhotic livers. Therefore, GPC3 may serve as a precancerous biomarker in cirrhotic livers.

Dysplastic nodules with glypican-3 positive immunostaining: a risk for early hepatocellular carcinoma

Glypican-3 (GPC3) has been reported to be a novel serum and histochemical marker for HCC. The positivity or negativity for GPC3 in hepatic precancerous lesions, such as dysplastic nodules (DN), has also been described. Moreover, our previous studies have demonstrated that some DN in liver cirrhosis represent monoclonal hyperplasia, and confirmed their neoplastic nature. However, additional studies must be performed to investigate further the relationship between DN with GPC3 positivity and HCC. Thus, we first investigated the expression of GPC3 in 136 HCC and 103 small DN (less than 1 cm in diameter) by immunohistochemical staining and determined the clonality of 81 DN from female patients using X-chromosome inactivation mosaicism and polymorphism of androgen receptor (AR) gene. Then we examined these samples for chromosomal loss of heterozygosity (LOH) at 11 microsatellite polymorphism sites. The results demonstrated that GPC3 immunoreactivity was detected in 103 of 136 HCC (75.7%) and 19 of 103 DN (18.4%), and the positive ratio correlated with HBsAg positivity. Clonality assays showed that 15 GPC3-positive DN from female patients, including 12 high-grade DN (HGDN), and 28 (42.4%) of 66 GPC3-negative DN, were monoclonal. In addition, among 19 GPC3-positive DN, chromosomal LOH was found at loci D6S1008 (100%, 19/19), D8S262 (52.6%, 10/19) and D11S1301 (57.9%, 11/19). However, the LOH frequency in GPC3-negative DN was 5.95% (5/84), 23.8% (20/84), and 4.76% (4/84) in three loci, respectively. Thus, we concluded that GPC3-positive DN, especially GPC3-positive HGDN, was really a late premalignant lesion of HCC.

Schistosoma mansoni infection: is it a risk factor for development of hepatocellular carcinoma?

The burden of hepatocellular carcinoma (HCC) in Egypt has been increasing with a doubling in the incidence rate in the past 10 years, which necessitates the investigation of the possible risk factors to its development. The present study aimed at investigating the role of Schistosoma mansoni infection as a risk factor for development of HCC. Five hundred parasite free mice were categorized into four groups: Group I (induction of carcinoma by diethylnitrosamine (DEN)), Group II (DEN+Infection), Group III (Infection) and Group IV (Control). Groups I and II were further subdivided into 4 subgroups according to the dose of DEN given. Serum samples from each group were examined for levels of tumor markers alpha fetoprotein (AFP) and ferritin by ELISA, then mice were sacrificed and subjected to histopathological examination of their livers. These were repeated every week till the end of the experiment. The results of the histopathological examination clarified the role of S. mansoni in enhancing and aggravating the carcinogenic effect of DEN; dysplastic changes appeared earlier, with a higher grade and with a smaller dose of DEN in Group II compared to Group I. Serum levels of tumor markers showed earlier statistically significant differences in Group II than in Group I when compared to Group IV. We conclude that S. mansoni accelerates hepatic dysplastic changes in the presence of other risk factors making cancer appear early and with a more aggressive nature, compared to the same risk in absence of schistosomiasis.

Comparative histomorphological review of rat and human hepatocellular proliferative lesions

In this comparative review, histomorphological features of common nonneoplastic and neoplastic hepatocyte lesions of rats and humans are examined using H&E-stained slides. The morphological similarities and differences of both neoplastic (hepatocellular carcinoma and hepatocellular adenoma) and presumptive preneoplastic lesions (large and small cell change in humans and foci of cellular alteration in rats) are presented and discussed. There are major similarities in the diagnostic features, growth patterns and behavior of both rat and human hepatocellular proliferative lesions and in the process of hepatocarcinogenesis. Further study of presumptive preneoplastic lesions in humans and rats should help to further define their role in progression to hepatocellular neoplasia in both species.

Hepatocarcinogenesis: imaging-pathologic correlation

Rapid advances in liver surgery, including liver transplantation, radiology, and pathology, have created a need for clinically relevant nomenclature for premalignant and early lesions of hepatocellular carcinoma (HCC). Precancerous lesions include dysplastic foci and dysplastic nodules (DNs) characterized by cytologic or structural atypia. Although imaging diagnosis is playing a crucial role in the evaluation of hepatocarcinogenesis and early diagnosis of HCC, it is still challenging to accurately characterize borderline nodules such as small arterially enhancing lesions or hypovascular nodules. This article discusses pathological and radiological features of these small nodular lesions and offers insights into the multistep process of hepatocarcinogenesis by describing the progression of pathologic change linking DNs to HCC.

Update on precursor and early lesions of hepatocellular carcinomas

CONTEXT

There is increasing evidence to support a multistep model of the process of human hepatocarcinogenesis. Precursor lesions are characterized by the appearance of dysplastic lesions in the form of microscopic dysplastic foci and macroscopic dysplastic nodules. There are 2 types of small hepatocellular carcinoma (HCC) (≤2 cm in diameter): (1) early HCC with an indistinct margin and (2) progressed HCC with a distinct margin. Pathologic diagnostic criteria for early HCC have recently been set up based on a consensus between Eastern and Western pathologists.

OBJECTIVE

To review the nomenclature, pathology, and biomarkers of precursor and early lesions of HCC.

DATA SOURCES

Literature review and illustrations from case materials were used.

CONCLUSIONS

Dysplastic foci are composed of large and small cell changes. Small cell change is considered to be a more advanced precursor lesion than large cell change, and large cell change is a rather heterogeneous lesion that may represent both reactive change and true dysplasia. Dysplastic nodules can be categorized as low or high grade according to the degree of atypia. High-grade dysplastic nodules have been reported to show molecular changes similar to HCC and have a high risk of malignant transformation. Early HCC, which may correspond to microinvasive carcinomas of other organs, is a well-differentiated HCC, and differential diagnosis between early HCC and high-grade dysplastic nodule is difficult. Identification of stromal invasion and application of a panel of markers (glypican-3, heat shock protein 70, and glutamine synthetase) is helpful for diagnosis of early HCC. Detection of precursor lesions of HCC is important in recognizing patients with higher risk of developing HCC, and diagnosis of early HCC can improve patient survival by allowing for early and adequate treatment.

Chronic viral hepatitis: the histology report

In chronic viral hepatitis, the role of liver biopsy as a diagnostic test has seen a decline, paralleled by its increasing importance for prognostic purposes. Nowadays, the main indication for liver biopsy in chronic viral hepatitis is to assess the severity of the disease, in terms of both necro-inflammation (grade) and fibrosis (stage), which is important for prognosis and therapeutic management. Several scoring systems have been proposed for grading and staging chronic viral hepatitis and there is no a general consensus on the best system to be used in the daily practice. All scoring systems have their drawbacks and all may be affected by sampling and observer variability. Whatever the system used, a histological score is a reductive approach since damage in chronic viral hepatitis is a complex biological process. Thus, scoring systems are not intended to replace the detailed, descriptive, pathology report. In fact, lesions other than those scored for grading and staging may have clinical relevance and should be assessed and reported. This paper aims to provide a systematic approach to the interpretation of liver biopsies obtained in cases of chronic viral hepatitis, with the hope of helping general pathologists in their diagnostic practice.

Pathology of chronic hepatitis B and chronic hepatitis C

Histologic evaluation of the liver is a major component in the medical management and treatment algorithm of patients with chronic hepatitis B (HBV) and chronic hepatitis C (HCV). Liver biopsy in these patients remains the gold standard, and decisions on treatment are often predicated on the degree of damage and stage of fibrosis. This article outlines the clinical course and serologic diagnosis of HBV and HCV for the clinician and the pathologist, who together have a close working relationship in managing patients with acute and chronic liver disease. The salient histologic features are elucidated in an attempt to provide the clinician with an understanding of the basic histopathology underlying chronic HCV and HBV.

Clonality of nodular lesions in liver cirrhosis and chromosomal abnormalities in monoclonal nodules of altered hepatocytes

AIMS

To investigate the clonality and chromosome abnormalities of nodules of altered hepatocytes (NAH) in liver cirrhosis and determine whether there is a genetic link between monoclonal NAH and hepatocellular carcinoma (HCC).

METHODS AND RESULTS

First, 93 nodules from nine hepatitis B virus (HBV)-related liver cirrhosis patients were dissected by laser microdissection. Next, genomic DNA was extracted, pretreated with Hpa II or Hha I, and amplified via nested polymerase chain reaction for the phosphoglycerate kinase and androgen receptor genes. Finally, the chromosomal aberrations of 12 monoclonal NAH were studied using array-based comparative genomic hybridization (array-CGH). Loss of X chromosomal inactivation mosaicism was demonstrated in three large regenerative nodules and 12 NAH with small cell change (SCC), indicating their neoplastic nature. Among the 60 NAH without SCC, 29 (48.33%) were shown to be monoclonal, whereas four glycogen-storing foci and 14 regenerative nodules were found to be polyclonal. Array-CGH analysis revealed chromosomal abnormalities in one NAH with SCC. Moreover, a part of chromosomal abnormalities in the NAH with SCC coincided with those in HCC.

CONCLUSIONS

Some (48.33%) NAH in HBV-associated cirrhosis, particularly all those with SCC, are already neoplastic lesions. Occurrence of SCC is a late event during NAH progression, suggesting a premalignant phenotype.

Intermediate hepatobiliary cells predict an increased risk of hepatocarcinogenesis in patients with hepatitis C virus-related cirrhosis

BACKGROUND & AIMS

The expression of biliary lineage markers such as cytokeratin (K) 7 by hepatocytes is thought to reflect an altered regeneration pathway recruiting a stem cell compartment, more prone to carcinogenesis. We aimed to investigate the presence of these so-called intermediate hepatobiliary cells (IHC) in liver biopsies of patients with hepatitis C-related cirrhosis and their potential influence on the subsequent occurrence of hepatocellular carcinoma (HCC).

METHODS

From a cohort of patients with hepatitis C-related cirrhosis, prospectively screened for HCC, we retrospectively selected those with a liver biopsy performed for the initial diagnosis of cirrhosis. Presence of IHC was recorded when foci of K7-positive, intermediate-sized hepatocytes were detected.

RESULTS

A total of 150 patients were included (87 men; mean age, 57 y; range, 19-84 y; body mass index, 25 kg/m(2)). After a median follow-up period of 4.85 years, HCC was diagnosed in 36 patients (24%). Baseline liver biopsy showed intermediate hepatobiliary cell foci in 61 patients (41%). Intermediate cells co-expressed both hepatocytes markers and the progenitor cell markers Ep-CAM and K19. The presence of intermediate hepatobiliary cells was associated independently with HCC occurrence (Fine and Gray model; hazard ratio, 2.48; 95% confidence interval, 1.24-4.96; P = .01). Other predictors of HCC were diabetes and low platelet count. The HCC annual incidence rate was significantly higher in patients with IHC compared with patients without (8.14% vs 3.12%, Gray's test, P = .003).

CONCLUSIONS

The aberrant expression of biliary K by hepatocytes in patients with hepatitis C virus-related cirrhosis is related independently to HCC occurrence.

Hepatocellular carcinoma: New and emerging risks

The underlying liver diseases that put patients at risk for the development of hepatocellular carcinoma (HCC) are well known. However, it is equally well known that not all patients with these conditions will develop HCC. Therefore within the disease groups (hepatitis B, cirrhosis, etc.,) there are other factors that indicate greater or lesser risk. Some markers of risk are common to all causes of HCC, such as cellular dysplasia, advancing age and male gender. Others factors are specific to individual diseases. This has been well established for hepatitis B in which viral load, genotype and antigen status are major contributors to increased risk of HCC. For both hepatitis B and hepatitis C attempts have been made to identify those individuals at greatest risk using data from large cohort studies. In addition to the common causes of liver disease that are recognized to be causes of HCC non-alcoholic fatty liver disease and possibly diabetes are newly emerging risk factors.

Hepatocellular carcinoma: epidemiology, surveillance, and diagnosis

Hepatocellular carcinoma (HCC) is increasing in incidence in many countries, and is the most common cause of death in patients with cirrhosis. With regular surveillance, small early HCC lesions can be identified. An algorithm has been developed that allows for diagnosis of these lesions. Very early HCC lesions have high cure rates with appropriate treatment. If all these factors are in place most HCCs can be cured.

Proliferative drive and liver carcinogenesis: too much of a good thing?

There have been innumerable studies published in the attempt to identify gene expression signatures in hepatocellular carcinoma (HCC). When all the regulators and targets of the differentially expressed genes are analyzed from larger studies, the most striking theme is upregulation of mitosis-promoting and cell proliferation genes in HCC compared with 'liver-specific gene clusters' in non-tumorous tissue. A major limitation of expression profiling is that it only provides a 'snapshot' of what is an evolving process and thus cannot distinguish the differences in gene expression that are primary effectors of dysregulated growth from those that represent downstream consequences. The development of HCC in a chronically diseased liver, often referred to as hepatocarcinogenesis, is a multistep process characterized by the progressive accumulation and interplay of genetic alterations causing aberrant growth, malignant transformation of liver parenchymal cells, followed by vascular invasion and metastasis. This review will discuss HCC precursor lesions, draw on the 'proliferation cluster' genes highlighted from HCC expression profiling studies, relate them to a selection of regulatory networks important in liver regeneration, cell cycle control and their potential significance in the pathogenesis of HCC or primary liver cancer.

Clonality and allelotype analyses of focal nodular hyperplasia compared with hepatocellular adenoma and carcinoma

AIM: To identify clonality and genetic alterations in focal nodular hyperplasia (FNH) and the nodules derived from it.

METHODS: Twelve FNH lesions were examined. Twelve hepatocellular adenomas (HCAs) and 22 hepatocellular carcinomas (HCCs) were used as references. Nodules of different types were identified and isolated from FNH by microdissection. An X-chromosome inactivation assay was employed to describe their clonality status. Loss of heterozygosity (LOH) was detected, using 57 markers, for genetic alterations.

RESULTS: Nodules of altered hepatocytes (NAH), the putative precursors of HCA and HCC, were found in all the FNH lesions. Polyclonality was revealed in 10 FNH lesions from female patients, and LOH was not detected in any of the six FNH lesions examined, the results apparently showing their polyclonal nature. In contrast, monoclonality was demonstrated in all the eight HCAs and in four of the HCCs from females, and allelic imbalances were found in the HCAs (9/9) and HCCs (15/18), with chromosomal arms 11p, 13q and 17p affected in the former, and 6q, 8p, 11p, 16q and 17p affected in the latter lesions in high frequencies (≥ 30%). Monoclonality was revealed in 21 (40%) of the 52 microdissected NAH, but was not found in any of the five ordinary nodules. LOH was found in all of the 13 NAH tested, being highly frequent at six loci on 8p, 11p, 13q and 17p.

CONCLUSION: FNH, as a whole, is polyclonal, but some of the NAH lesions derived from it are already neoplastic and harbor similar allelic imbalances as HCAs.

Large liver cell change in hepatitis B virus-related liver cirrhosis

Large liver cell change (LLCC) refers to microscopic lesions often found in various chronic liver diseases; however, its nature is still controversial. Thirty-four formalin-fixed and 19 fresh frozen hepatitis B virus (HBV)-related cirrhosis samples were examined for the presence of LLCC, small liver cell change (SLCC), and hepatocellular carcinoma (HCC). The cell cycle checkpoint status (p21, p27, p16, Tp53), cell dynamics (proliferating cell nuclear antigen, Ki-67, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling, M30), DNA damage (gamma-H2AX [H2A histone family, member X]), telomere lengths, chromosomal instability (micronuclei index), and senescence-associated beta-galactosidase (SA-beta-Gal) activity were evaluated using an in situ approach and compared to those in normal liver (n = 5) and liver with chronic cholestasis (34 cases of hepatolithiasis and three cases of primary biliary cirrhosis). In HBV-related cirrhosis, the p21, p27, and p16 cell cycle checkpoint markers were activated in normal-looking cirrhotic hepatocytes (NLCH), but diminished gradually from LLCC, SLCC, to HCC, with an increase in Tp53 expression. There was a general decrease in telomere length from NLCH, LLCC, SLCC, to HCC. Micronuclei, gamma-H2AX foci, and net cellular gain were significantly increased from normal hepatocytes, NLCH, LLCC, SLCC, to HCC. The SA-beta-Gal activity was weaker in LLCC compared to NLCH and absent in SLCC and HCC. In contrast, cholestatic LLCC showed retained expression of cell cycle checkpoint markers and decreased net cellular gain compared to adjacent normal-looking hepatocytes. HBV-related LLCC showed significantly higher Tp53 labeling index, gamma-H2AX labeling index, and micronuclei index; shorter telomere length; decreased SA-beta-Gal activity; and increased net cellular gain compared to cholestatic LLCC.

CONCLUSION

The nature of LLCC is rather heterogeneous depending on the biological setting. The characteristics of HBV-related LLCC are more consistent with dysplastic rather than merely reactive hepatocytes, whereas cholestatic LLCC more likely represents reactive change with more stringent cell cycle checkpoint control.

Use of X-chromosome inactivation pattern and laser microdissection to determine the clonal origin of focal nodular hyperplasia of the liver

AIM

To determine the clonal origin of the whole lesion and each nodule of focal nodular hyperplasia (FNH) and elucidate its nature, simultaneously comparing the clonal composition with hepatocellular adenoma (HA).

METHODS

Nine FNHs from eight women, two HAs and four hepatocellular carcinomas (HCCs) were examined by clonality assays based on X-chromosomal inactivation mosaicism in females and laser microdissection. Genomic DNA was isolated from each nodule, the whole lesion and surrounding liver parenchyma, pretreated with Hpa II or Hha I, and amplified via nested PCR for phosphoglycerate kinase (PGK) and androgen receptor (AR) genes. The single nucleotide polymorphism at the PGK locus was identified by incubation with Bst XI and agarose gel electrophoresis, and the CAG repeat length polymorphism at AR locus was revealed on denaturing polyacrylamide gels and visualised by silver staining.

RESULTS

Monoclonality was confirmed in both of the two HAs and all of the four HCCs examined, while polyclonality was shown in all nine FNHs as determined by the whole lesions, demonstrating their distinction from neoplastic lesions. A total of 108 nodules, including 96 nodules of altered hepatocytes (NAH) and 12 ordinary regenerative nodules (ORN), were microdissected from eight of the nine FNH lesions. Loss of X-chromosomal inactivation mosaicism was demonstrated in 39 (40.6%) of 96 NAHs, indicating the monoclonal, neoplastic nature. In contrast, polyclonality was demonstrated in all of the 12 ORNs and the surrounding liver parenchyma.

CONCLUSIONS

FNH is composed of numerous NAHs and ORNs. The whole lesion shows a polyclonal cell composition, but neoplastic transformation has occurred in some of the nodules. Clonal assay is useful for its distinction from HA, and sampling the whole or larger part of the lesion is necessary.

Liver biopsy findings in chronic hepatitis B

Liver biopsy plays a central role in treatment algorithms in patients with hepatitis B and remains the gold standard for evaluating hepatic pathology. The pathology of hepatitis B is diverse and reflects the natural history of infection. An acute hepatitic pattern with lobular disarray is seen in acute infection, during acute flares of disease, and with acute hepatitis D superinfection. In chronic hepatitis B, inflammation is less pronounced in the immune-tolerant phase and is prominent during immune-mediated viral clearance. Active inflammation appears to be the driving force for development of fibrosis. Inflammatory grades and fibrosis stage are assigned as is done for hepatitis C. Although current management guidelines recommend liver biopsies only in select patients based on age, viral levels, and hepatitis B e antigen status, these clinical and biochemical parameters do not show consistent correlations with liver histology. Liver biopsy also helps identify preneoplastic lesions including large cell and small cell change. Unlike in other causes of chronic hepatitis, immunostains are widely used and can help determine the phase of infection. Liver biopsies can also identify additional pathology that may contribute to liver disease such as steatohepatitis, iron overload, autoimmune hepatitis, and drug-induced injury. Thus, liver biopsy can play an important role in staging and grading chronic hepatitis B and should be more widely used in assessing the need for therapy.

Two-photon autofluorescence dynamics imaging reveals sensitivity of intracellular NADH concentration and conformation to cell physiology at the single-cell level

Reduced nicotinamide adenine dinucleotide, NADH, is a major electron donor in the oxidative phosphorylation and glycolytic pathways in cells. As a result, there has been recent resurgence in employing intrinsic NADH fluorescence as a natural probe for a range of cellular processes that include apoptosis, cancer pathology, and enzyme kinetics. Here, we report on two-photon fluorescence lifetime and polarization imaging of intrinsic NADH in breast cancer (Hs578T) and normal (Hs578Bst) cells for quantitative analysis of the concentration and conformation (i.e., free-to-enzyme-bound ratios) of this coenzyme. Two-photon fluorescence lifetime imaging of intracellular NADH indicates sensitivity to both cell pathology and inhibition of the respiratory chain activities using potassium cyanide (KCN). Using a newly developed non-invasive assay, we estimate the average NADH concentration in cancer cells (168+/-49 microM) to be approximately 1.8-fold higher than in breast normal cells (99+/-37 microM). Such analyses indicate changes in energy metabolism and redox reactions in normal breast cells upon inhibition of the respiratory chain activity using KCN. In addition, time-resolved associated anisotropy of cellular autofluorescence indicates population fractions of free (0.18+/-0.08) and enzyme-bound (0.82+/-0.08) conformations of intracellular NADH in normal breast cells. These fractions are statistically different from those in breast cancer cells (free: 0.25+/-0.08; bound: 0.75+/-0.08). Comparative studies on the binding kinetics of NADH with mitochondrial malate dehydrogenase and lactate dehydrogenase in solution mimic our findings in living cells. These quantitative studies demonstrate the potential of intracellular NADH dynamics (rather than intensity) imaging for probing mitochondrial anomalies associated with neurodegenerative diseases, cancer, diabetes, and aging. Our approach is also applicable to other metabolic and signaling pathways in living cells, without the need for cell destruction as in conventional biochemical assays.

Fine-needle aspiration cytology to distinguish dysplasia from hepatocellular carcinoma with different grades

BACKGROUND

Distinguishing dysplasia from hepatocellular carcinoma (HCC) by fine-needle aspiration (FNA) cytology is difficult. The aim of this study was to diagnose HCC and the distinction of liver cell dysplasia from HCC with different grades by interpreting and scoring the cyto-morphological features.

METHODS

Eighty-three cirrhotic patients undertook a sonography-guided FNA and subsequent needle biopsy for the tumor. HCC was confirmed in 68 cases and cirrhosis with dysplasia in 15 cases by pathology and follow-up for longer than 2 years. Eighteen cytological features were scored as degree of one, two or three according to their presence or prominence.

RESULTS

Two cases of well-differentiated HCC were diagnosed as negative for HCC initially. The sensitivity, specificity, false positive, false negative and accuracy were 97%, 100%, 0%, 3% and 97.6% for FNA cytology in the diagnosis of HCC, respectively. The score of dysplasia was 20.8 +/- 1.3 (mean +/- SD) and lower than 26.2 +/- 3.4 in Edmondson's grade I HCC (P < 0.01), 28.9 +/- 2.9 in grade II HCC (P < 0.01), and 34.9 +/- 4.3 in grade III/IV HCC (P < 0.01). The score was also significantly lower in grade II HCC than in grade III/IV HCC (P < 0.01).

CONCLUSIONS

FNA yielded a high accuracy in the distinction of dysplasia from HCC with different grades. There is a good correlation in cyto-morphological scores of liver cell dysplasia and HCC with different grades. Dysplasia displayed the lowest score and the score increased in order from dysplasia to grade III/IV HCC.

Predictive value of liver cell dysplasia for development of hepatocellular carcinoma in patients with chronic hepatitis B

GOALS

We aimed to determine whether the presence of large liver cell dysplasia (LLCD) and/or small LCD (SLCD) in chronic hepatitis B is a risk factor for hepatocellular carcinoma (HCC) development.

BACKGROUND

A close relationship between LLCD/SLCD and hepatitis B virus has been observed and SLCD has been proposed to be a putative precursor of HCC, whereas the significance of LLCD is still controversial.

STUDY

One hundred eighty-one patients with chronic hepatitis B who underwent needle liver biopsy were evaluated for the presence of LLCD/SLCD. The predictive value of LLCD/SLCD for HCC development was assessed.

RESULTS

LLCD and SLCD were present at initial biopsy in 82 (45%) and 17 (9%) patients, respectively. During the mean follow-up of 115+/-48 months, 19 (10%) cases were diagnosed of HCC, of which 13 (76%) and 3 (17%) cases had demonstrated LLCD and SLCD, respectively, at initial evaluation. The patients with LLCD showed a significantly higher cumulative probability of HCC development than those without LLCD (P=0.016). The risk of HCC development in the presence of LLCD was approximately 3-fold, with positive and negative predictive values of 15.9% and 94.9%, respectively. The patients with SLCD showed no significant difference in cumulative probability of HCC development compared with those without (P>0.05).

CONCLUSIONS

LLCD in chronic hepatitis B is considered to be one of the risk factors for HCC development and its presence may help to identify a high-risk subgroup of patients requiring more intensive screening for HCC.

Hepatic precancerous lesions and small hepatocellular carcinoma

Precancerous lesions that may be detected in chronically diseased, usually cirrhotic livers, include: clusters of hepatocytes with atypia and increased proliferative rate (dysplastic foci) that usually represent an incidental finding in biopsy or resection specimens; and grossly evident lesions (dysplastic nodules) that may be detected on radiologic examination. There are two types of small hepatocellular carcinoma (HCC) (defined as HCC that measures less than 2 cm): early HCC, which is well-differentiated and has indistinct margins; and distinctly nodular small HCC, which is well- or moderately differentiated, and is usually surrounded by a fibrous capsule. Precise diagnosis of precancerous and early cancerous lesions by imaging methods is often difficult or impossible. Detection of a dysplastic lesion in a biopsy specimen is a marker of increased risk for HCC development, and warrants increased surveillance. High-grade dysplastic nodules and small HCCs should be treated by local ablation, surgical resection, or liver transplantation.

Liver biopsy assessment in chronic hepatitis

Liver biopsy has been a major diagnostic tool in the evaluation of individuals with chronic hepatitis for many decades and remains the most direct way of visualizing hepatic necroinflammation and fibrosis. In chronic viral hepatitis B and C, immune attack on hepatocytes bearing viral antigens results in the entry of lymphocytes and other effector cells through the portal tracts from which other lesions may evolve, including interface and lobular hepatitis as well as fibrosis or cirrhosis. Classification systems have been developed in order to provide semiquantitative grading of necroinflammation and staging of fibrosis and include the Scheuer, Batts and Ludwig, Ishak, and METAVIR systems. This review provides an historical perspective on histopathological methods of analyzing chronic hepatitis, describes the essential criteria of each of the major scoring systems and discusses problems related to sampling error, observer variation, and specimen size.

EUS for detection of the hepatocellular carcinoma: results of a prospective study

BACKGROUND

Early detection of hepatocellular carcinoma (HCC) and accurate determination of the number of lesions are critical in determining eligibility for liver transplantation or resection. Current diagnostic modalities (CT and magnetic resonance imaging [MRI]) often miss small lesions.

OBJECTIVE

To compare the accuracy of the EUS with CT for the detection of primary tumors of the liver.

DESIGN

Prospective single-center study.

SETTING

Academic medical center.

PATIENTS

Subjects at high risk of HCC (hepatitis B, hepatitis C, or alcoholic cirrhosis) were enrolled.

INTERVENTIONS

US, CT, MRI, and EUS examinations of the liver were performed. Liver lesions identified during EUS underwent EUS-guided FNA (EUS-FNA).

RESULTS

Seventeen patients were enrolled in the study. Nine of these patients had liver tumors (HCC, 8; cholangiocarcinoma, 1). EUS-FNA established a tissue diagnosis in 8 of the 9 cases. The diagnostic accuracy of US, CT, MRI, and EUS/EUS-FNA were 38%, 69%, 92%, and 94%, respectively. EUS detected a significantly higher number of nodular lesions than US (P = .03), CT (P = .002), and MRI (P = .04). For HCC lesions, a trend was observed in favor of EUS for the detection of more lesions than US (8 vs 2; P = .06) and CT (20 vs 8; P = .06). No complications were observed as a result of EUS-FNA.

LIMITATIONS

Small sample size.

CONCLUSIONS

EUS-FNA is a safe and accurate test for the diagnosis of HCC. EUS increases the accuracy of intrahepatic staging of the HCC by delineation of lesions, which are missed by CT and MRI. We recommend EUS for suspected HCC, particularly in cases that are being considered for liver transplantation.

Enhancement patterns and signal-intensity characteristics of small hepatocellular carcinoma in cirrhosis: pathologic basis and diagnostic challenges

Recent pathologic studies of hepatic resection and transplantation specimens have elucidated the morphologic features of the precancerous lesions and small hepatocellular carcinomas (HCCs) arising in cirrhotic livers. Small HCCs measuring less than 2 cm in diameter are of two types: vaguely nodular, well-differentiated tumors, also known as "early" HCCs, and distinctly nodular tumors, with histologic features of "classic" HCC. The precancerous lesions include dysplastic foci and dysplastic nodules. "Classic" small HCCs are supplied by nontriadal arteries, whereas early HCCs and dysplastic nodules may receive blood supply from both portal tracts and nontriadal arteries. The similarities in blood supply of these three types of nodular lesions result in significant overlap of findings on dynamic imaging. Nevertheless, small HCCs sometimes display characteristic radiologic features, such as "nodule-in-nodule" configuration and "corona enhancement" pattern. Moreover, various histologic features of these nodular lesions may also be related to a variety of signal intensities and attenuation coefficients, while the presence of cirrhosis is known to limit the sensitivity and specificity of any imaging modality, due to liver inhomogeneity. Because of these reasons, imaging findings of nodular lesions in cirrhotic livers are often inconclusive, emphasizing the need for a better understanding of these imaging features.

Telomere shortening and inactivation of cell cycle checkpoints characterize human hepatocarcinogenesis

Telomere shortening and inactivation of cell cycle checkpoints characterize carcinogenesis. Whether these molecular features coincide at specific stages of human hepatocarcinogenesis is unknown. The preneoplasia-carcinoma sequence of human HCC is not well defined. Small cell changes (SCC) and large cell changes (LCC) are potential precursor lesions. We analyzed hepatocellular telomere length, the prevalence of DNA damage, and the expression of p21 and p16 in biopsy specimens of patients with chronic liver disease (n = 27) that showed different precursor lesions and/or HCC: liver cirrhosis (n = 25), LCC (n = 26), SCC (n = 13), and HCC (n = 13). The study shows a decrease in telomere length in nondysplastic cirrhotic liver compared with normal liver and a further significant shortening of telomeres in LCC, SCC, and HCC. HCC had the shortest telomeres, followed by SCC and LCC. Hepatocytes showed an increased p21 labeling index (p21-LI) at the cirrhosis stage, which remained elevated in most LCC. In contrast, most SCC and HCC showed a strongly reduced p21-LI. Similarly, p16 was strongly expressed in LCC but reduced in SCC and not detectable in HCC. gammaH2AX-DNA-damage-foci were not detected in LCC but were present in SCC and more frequently in HCC. These data indicate that LCC and SCC represent clonal expansions of hepatocytes with shortened telomeres.

CONCLUSION

The inactivation of cell cycle checkpoints coincides with further telomere shortening and an accumulation of DNA damage in SCC and HCC, suggesting that SCC represent more advanced precursor lesions compared with LCC.

Hyperintense nodules on non-enhanced T1-weighted gradient-echo magnetic resonance imaging of cirrhotic liver: fate and clinical implications

PURPOSE

To investigate the fate of hyperintense hepatic nodules on nonenhanced T1-weighted (T1w) gradient-echo (GRE) magnetic resonance (MR) images in cirrhotic patients.

MATERIALS AND METHODS

A total of 79 cirrhotic patients with hyperintense nodules (>5 mm) on precontrast opposed-phase (repetition time (TR)/echo time (TE) = 140/2.7 msec) GRE images from initial MRI without T2-weighted (T2w) hyperintensity or arterial hypervascularity were subjected to analysis of subsequent MR images obtained at intervals of 12-56 months (mean = 24.5 months). Multiplicity of hyperintense nodules (group A, up to 8; group B, >8) was correlated with follow-up changes.

RESULTS

Group B patients were younger (P = 0.003) than group A patients (mean = 47.5 and 56.2 years, respectively). In 66 group A patients, 39 out of 143 lesions (27%) were enlarged, including 20 malignantly transformed or borderline lesions. Of the 104 lesions (the eight largest lesions in each patient) in 13 group B patients, only three (2.9%) were enlarged. The results of best- and worst-case analyses showed that overall the lesions were benign in 91% and 82% of patients, respectively.

CONCLUSION

T1w hyperintense nodules without T2w hyperintensity or arterial hypervascularity in the cirrhotic liver are benign in most cases. In younger patients with numerous macronodules, almost all of these lesions follow a benign course.

Large liver cell dysplasia: a controversial entity

Large cell change (LCC) is a noncommittal term used today to indicate liver cell dysplasia of the large cell type. Dysplasia was deleted from the original definition because not enough evidence has been collected over time to support premalignancy. LCC is a microscopically well-defined lesion, usually found in cirrhosis, whose origin, natural history, and fate are still debated. Different morphologic, phenotypic, molecular and clinical studies have been performed to address the issue of the dysplastic versus reactive nature of this lesion. The aim of this review is to critically evaluate the contributions to the topic and to underline that the heterogeneity of the lesion is an important issue to be taken into account for our biological understanding of it. While LCC has important morphologic analogies in experimental liver carcinogenesis, no comparable lesions are known in solid non-liver parenchymal human tissues that morphologically feature dysplasia, but in which it is uncertain whether the lesions are reactive or preneoplastic. The debate over the lesion may be useful in learning the actual limits of morphology and how additional information can be gained by looking inside the cells.