Hepatospecific MR contrast agent uptake on hepatobiliary phase can be used as a biomarker of marked ß-catenin activation in hepatocellular adenoma.

OBJECTIVES: To assess the value of hepatospecific MR contrast agent uptake on hepatobiliary phase (HBP) images to detect marked activation of the ß-catenin pathway in hepatocellular adenomas (HCAs). METHODS: This multicentric retrospective IRB-approved study included all patients with a pathologically proven HCA who underwent gadobenate dimeglumine-enhanced liver MRI with HBP. Tumor signal intensity on HBP was first assessed visually, and lesions were classified into three distinct groups-hypointense, isointense, or hyperintense-according to the relative signal intensity to liver. Uptake was then quantified using the lesion-to-liver contrast enhancement ratio (LLCER). Finally, the accuracy of HBP analysis in depicting marked ß-catenin activation in HCA was evaluated. RESULTS: A total of 124 HCAs were analyzed including 12 with marked ß-catenin activation (HCA B+). Visual analysis classified 94/124 (76%), 12/124 (10%), and 18/124 (14%) HCAs as being hypointense, isointense, and hyperintense on HBP, respectively. Of these, 1/94 (1%), 3/12 (25%), and 8/18 (44%) were HCA B+, respectively (p < 0.001). The LLCER of HCA B+ was higher than that of HCA without marked ß-catenin activation in the entire cohort (means 4.9 ± 11.8% vs. - 19.8 ± 11.4%, respectively, p < 0.001). A positive LLCER, i.e., LLCER ≥ 0%, had 75% (95% CI 43-95%) sensitivity and 97% (95% CI 92-99%) specificity, with a LR+ of 28 (95% CI 8.8-89.6) for the diagnosis of HCA B+. CONCLUSIONS: Hepatospecific contrast uptake on hepatobiliary phase is strongly associated with marked activation of the ß-catenin pathway in hepatocellular adenoma, and its use might improve hepatocellular adenoma subtyping on MRI. KEY POINTS: • Tumor uptake on hepatobiliary phase in both the visual and quantitative analyses had a specificity higher than 90% for the detection of marked ß-catenin activation in hepatocellular adenoma. • However, the sensitivity of visual analysis alone is inferior to that of LLCER quantification on HBP due to the high number of HCAs with signal hyperintensity on HBP, especially those developed on underlying liver steatosis.

Interest of contrast-enhanced sonography to identify focal nodular hyperplasia with sinusoidal dilatation.

BACKGROUND AND AIMS: Focal nodular hyperplasia with major sinusoidal dilatation (FNH-sd) is a misleading entity, with some features resembling inflammatory hepatocellular adenoma (HCA). We aimed to assess the performance of contrast-enhanced ultrasound (CEUS) for the diagnosis of FNH-sd. METHODS: Four histologically proven FNH-sd nodules in four patients were investigated with both MRI and CEUS imaging. Sinusoidal dilatation was focally visible in all cases in histology. RESULTS: In MRI, in all the four cases, lesions were hypervascular in arterial phase, with high intensity in T2-weighted sequence imaging and persistent enhancement in the delayed gadolinium-enhanced phase. These MRI features were more indicative of HCA than FNH. On the other hand, CEUS showed a very specific centrifugal filling followed by a strong, homogeneous enhancement of the whole lesion. CONCLUSION: CEUS seems to be an essential step for the diagnosis of non-typical FNH, such as FNH-sd. This small series highlights the interest of performing both CEUS and MRI for the diagnosis of atypical focal liver lesions, such as FNH-sd.

Can elastometry be used for a better identification of cirrhosis?

Increased stiffness has been directly associated to fibrosis. Stage 4 fibrosis defines cirrhosis. Can elastometry (transient elastography, acoustic radiation force impulse imaging) be used for a better identification of cirrhosis? The answer is obviously yes, provided hepatologists, radiologists, pathologists, and biologists combine their expertise because severe chronic liver disease is a complex subject. Considering the pathogenesis of cirrhosis, it is likely that factors such as parenchymal extinction (leading to atrophy of the liver mass with approximation of portal tracts and hepatic veins) and exudation (congestion) play a role in liver stiffness not mentioning heart failure, liver necrosis and extrahepatic cholestasis. Neglecting these factors, elastometry will lead too often to a wrong appreciation of the degree and type of liver damage and eventually to wrong medical decision.

[Expression of the elastic fibers components during the fœtal liver development]. / Expression des composants de la matrice élastique au cours du développement hépatique fœtal.

Elastic fibers are composed of microfibrils containing fibrillin-1 and an elastic component, elastin. Microfibrils may not be associated with elastin. In the adult liver, fibrillin-1 and elastin are coexpressed within the stroma and portal tracts vessel walls. Fibrillin-1 is expressed alone around the bile ducts and within the Disse space. There is little work that has studied the elastic fiber organization during the fœtal liver development. Here, we studied the expression of fibrillin-1 and elastin by immunohistochemistry on 20 cases of fœtal liver. During the development of the portal tract, the two components are coexpressed on interstitial elastic fibers and within vessel walls. Fibrillin-1 is expressed alone around the bile structures during their maturation. Unlike adult liver, fibrillin-1 is expressed on thin and very irregular microfibrils within the Disse space. Our study shows that the elastic matrix development in the portal tract follows the development of the different structures, notably biliary structures. In the Disse space, microfibrils are not continuous. Their maturation may be in relation with the change of the hepatic blood flow after birth.

Cirrhosis: what else?

When the term cirrhosis was coined two centuries ago by Laennec, it designates by definition an end stage irreversible liver disease. Nowadays this word encompasses a whole range of disorders including some degree of reversibility for the early stage. It is therefore of prime importance to define the stages of the fibrotic process, based on the integration of knowledge about liver structure and function. In addition to morphological data, modern imaging techniques coupled to non-invasive biomarkers will probably help to better define and denominate this heterogeneous entity.

Human cirrhosis: monoclonal regenerative nodules derived from hepatic progenitor cells abutting ductular reaction.

Cirrhosis is a premalignant condition leading to hepatocellular carcinoma. Cirrhotic nodules are surrounded by a rim of CK 7/CK19-positive biliary cells termed ductular reaction. Half of all regenerative cirrhotic nodules are thought to be monoclonal by studying the pattern of inactivation of the X-linked human androgen receptor gene (HUMARA). Using a new technique for lineage tracing in human liver based on the identification in the mitochondrial DNA of mutations in the cytochrome c oxidase (CCO) gene, the authors discovered that 20% of regenerative nodules were monoclonal; in addition they showed that hepatic progenitor cells within abutting CCO-deficient cells of the ductular reaction had the same mutations as the adjacent regenerative nodule, indicating a common cell origin. It is the first direct evidence that regenerative nodules in cirrhosis can be derived from hepatic progenitor cells.

Spontaneous regression of focal nodular hyperplasia: a pathological report.

Focal nodular hyperplasia (FNH) is a benign tumour of the liver, occurring in 0.6-3% of the general population. Most lesions are diagnosed incidentally. With the increasing use and improvement of diagnostic imaging, FNH is being observed more often. It has been shown, using radiological approaches, that most FNH remain stable, or even regress, over a long follow-up period. In addition, it is extremely rare that FNH were discovered in elderly. However, to our knowledge, there is no pathological report illustrating the regression of FNH. We report here a case showing the pathological changes occurring during the regression phase of FNH, with dense fibrous tissue mixed with arteries replacing hepatocytes nodules.

Differential effects of inactivated Axin1 and activated beta-catenin mutations in human hepatocellular carcinomas.

Perturbations to the Wnt signaling pathway have been implicated in a large proportion of human hepatocellular carcinomas (HCCs). Activating beta-catenin mutations and loss of function mutations in Axin1 are thought to be functionally equivalent. We examined the Wnt pathway in HCC by comparing the expression of beta-catenin target genes and the level of beta-catenin-dependent transcriptional activation, in 45 HCC tumors and four cell lines. Among these samples, beta-catenin and AXIN1 were mutated in 20 and seven cases, respectively. We found a significant correlation between activated beta-catenin mutations and overexpression of mRNA for the target genes glutamine synthetase (GS), G-protein-coupled receptor (GPR)49 and glutamate transporter (GLT)-1 (P=0.0001), but not for the genes ornithine aminotransferase, LECT2, c-myc and cyclin D1. We also showed that GS is a good immunohistochemical marker of beta-catenin activation in HCC. However, we observed no induction of GS, GPR49 or GLT-1 in the five inactivated Axin1 tumors. Beta-catenin-dependent transcriptional activation in two Axin1-mutated HCC cell lines was much weaker than in beta-catenin-mutated cell lines. Our results strongly suggest that in HCC, contrary to expectation, the loss of function of Axin1 is not equivalent to the gain of function of beta-catenin. Our results also suggest that the tumor suppressor function of Axin1 in HCC may be related to another, non-Wnt pathway.

Genomic alteration is not associated with fatty and clear cell change in hepatocellular carcinomas and its precursor nodular lesions in cirrhotic liver.

BACKGROUND: The aim of this study was to investigate whether fatty and clear cell areas in large regenerative nodules (LRN), dysplastic nodules (DN), and hepatocellular carcinoma (HCC) show higher degree of genomic mutation compared to non-fatty/clear cell area in the same nodule or non-lesional tissue. METHODS: We examined 22 nodular lesions (9 HCC, 5 DN and 8 LRN) from seven cirrhotic livers removed at transplantation. Frozen sections were used for manual microdissection of areas with fatty/clear cell change. DNA from microdissected tissue was amplified using arbitrarily primed polymerase chain reaction (AP-PCR), and PCR products were run on polyacrilamide gel generating a "fingerprint" band pattern. Autoradiographs were analysed using Adobe Photoshop version 6.0. Fingerprints from lesional tissue were compared to reference tissue and the total number of bands in excess or defect was calculated and divided by the total number of bands identified, obtaining the genomic damage fraction (GDF). RESULTS: Increasing GDF average values were seen from cirrhotic liver (0.13+/-0.04), to LRN (0.16+/-0.1), DN (0.28+/-0.08) and HCC (0.30+/-0.07). A statistically significant difference in GDF values was documented between cirrhotic liver and DN (p=0.008) and HCC (p=0.005) and between HCC and LRN (p=0.02). No significant difference was documented between DN and HCC, and between LRN and cirrhotic liver. Eleven nodules containing fat/clear cell areas were compared to the other 11 nodules without fat/clear cell areas. The GDF was not different between the two groups: 0.29+/-0.11 versus 0.25+/-0.12; p=0.5. The average value of genomic damage fraction between fat/clear cell areas (0.29+/-0.11) and no fat/clear cell areas (0.25+/-0.1) within the same nodules were not significantly different (p=0.11). CONCLUSION: Fatty and clear cell change in nodular lesions in cirrhotic liver may be an epigenetic phenotypic modification caused by microenvironmental factors such as ischaemia rather than indicating areas of increased malignant potential per se.

Investigation of liver fibrosis in clinical practice.

The liver is composed of different hepatic fibrogenic cells: hepatic stellate cells, portal fibroblasts, fibroblasts of the Glisson capsule surrounding the liver and vascular smooth muscle cells and the second layer cells present around centrolobular veins. During liver disease, one or several populations of these cells are activated, transformed into myofibroblasts and secrete the extra-cellular matrix. There are markers to identify hepatic stellate cells either quiescent (CRBP-1) or activated (alpha-smooth muscle actin). Liver biopsy, the current "gold-standard" to estimate liver fibrosis cannot be used anymore as a "gold standard". Furthermore, it is a costly procedure with adverse effects feared by patients and clinicians. Alternative to liver biopsy using non-invasive-tests or technics include FibroTest-ActiTest, transient-elastography, hepatic vein transit time using contrast ultrasonography, magnetic resonance imaging. As a routine test, the FibroTest-ActiTest is a validated one for patients with chronic hepatitis C. The advantage of the non-invasive tests or technics is that they provide a rapid and quantitative estimation of fibrosis. With these new methods, it is possible to follow the progression of the disease and its regression either spontaneously or under treatment. In conclusion, clinicians have in their hands several painless tools to explore liver fibrosis that can be easily repeated.

Association of Helicobacter species with hepatitis C cirrhosis with or without hepatocellular carcinoma.

BACKGROUND AND AIMS: Recent studies have suggested that bacterial coinfection with Helicobacter species in patients already infected with hepatitis C virus (HCV) could be involved in the development of cirrhosis and hepatocellular carcinoma (HCC). A retrospective cross sectional study was performed in order to explore the association between Helicobacter species and HCV associated liver diseases. METHODS: The presence of Helicobacter species was tested by polymerase chain reaction on liver samples from four groups of patients. RESULTS: Helicobacter 16S rDNA was found in only 4.2% of liver samples from control patients (n=24) and in 3.5% of liver samples from patients with non-cirrhotic chronic hepatitis C (n=29) while it was found in 68.0% of liver samples from patients with HCV positive cirrhosis without HCC (n=25) as well as in 61.3% of cirrhotic liver samples from patients with HCV positive cirrhosis and HCC (n=31). In addition, when the HCC tumour tissue was tested (n=21), 90.5% of samples were positive. DNA from Helicobacter pylori- and Helicobacter pullorum-like organisms was found. CONCLUSIONS: There is an association between the presence of Helicobacter species DNA in the liver and hepatitis C cirrhosis, with or without HCC. Indeed, the presence of these bacteria could be the result of structural changes in the liver. Alternatively, Helicobacter species could be a co-risk factor in HCV chronic liver diseases. This result warrants prospective studies to determine the possible causal role of these bacteria in the progression of chronic hepatitis C.

Classification tool for the systematic histological assessment of hepatocellular carcinoma, macroregenerative nodules, and dysplastic nodules in cirrhotic liver.

AIM: To design a classification tool for the histological assessment of hepatocellular carcinoma (HCC), dysplastic nodules (DN), and macroregenerative nodules (MRN) in cirrhotic liver. METHODS: Two hundred and twelve hepatocellular nodules (106 HCC; 74 MRN; 32 DN) were assessed systematically, quantitatively, and semiquantitatively as appropriate for 10 histological features that have been described as helpful in distinguishing small HCC, DN, and MRN in cirrhotic livers. The data were analyzed by multiple correspondence analysis (MCA). RESULTS: MCA distributed HCC, DN, and MRN as defined by traditional histological evaluation as well as the individual histological variables, in a "malignancy scale". Based on the MCA data representation, we created a classification tool, which categorizes an individual nodular lesion as MRN, DN, or HCC based on the balance of all histological features (i.e., vascular invasion, capsular invasion, tumor necrosis, tumor heterogeneity, reticulin loss, capillarization of sinusoids, trabecular thickness, nuclear atypia, and mitotic activity). The classification tool classified most (83%) of a validation set of 47 nodules in the same way as the routine histological assessment. No discrepancies were present for DN and MRN between the routine histological assignment and the classification tool. Of 25 HCC assigned by routine assessment in the validation set, 8 were assigned to the DN category by the classification tool. CONCLUSION: We have designed a classification tool for the histological assessment of HCC and its putative precursors in cirrhotic liver. Application of this tool systematically records histological features of diagnostic importance in the evaluation of small HCC.

Expression of somatostatin receptors in normal and cirrhotic human liver and in hepatocellular carcinoma.

BACKGROUND: Somatostatin analogues have been used with conflicting results to treat advanced hepatocellular carcinoma (HCC). The aim of this study was to investigate expression of somatostatin receptor (SSTR) subtypes in human liver, and to examine the effect of selective SSTR agonists on proliferation, apoptosis, and migration of hepatoma cells (HepG2, HuH7) and hepatic stellate cells (HSCs). METHODS: Expression of SSTRs in cell lines, normal and cirrhotic liver, and HCC was examined by immunohistochemistry and reverse transcription-polymerase chain reaction. Effects of SSTR agonists on proliferation and apoptosis of tumour cells and HSCs were assessed by the 5-bromo-2' deoxyuridine and TUNEL methods, respectively. The influence of SSTR agonists on migration was investigated using Boyden chambers. RESULTS: In normal liver, both hepatocytes and HSCs were negative for all five SSTRs. Cirrhotic liver and HCC as well as cultured hepatoma cells and HSCs expressed all five SSTRs, both at the protein and mRNA levels, except for HuH7 cells which did not immunoreact with SSTR3. None of the agonists influenced proliferation or apoptosis. However, compared with untreated cells, L-797,591, an SSTR1 agonist, reduced migration of HepG2, HuH7, and HSCs significantly to 88 (7)% (p<0.05), 83 (11)% (p<0.05), and 67 (13)% (p<0.01), respectively. CONCLUSIONS: Cirrhotic liver and HCC express SSTRs. Although the somatostatin analogues used in this study did not affect proliferation and apoptosis, stimulation of SSTR1 may decrease invasiveness of HCC by reducing migration of hepatoma cells and/or HSCs. Clinical trials evaluating somatostatin analogues for the treatment of HCC should take these findings into account.

[Microvenular hemangioma]. / Hémangiome microveinulaire.

INTRODUCTION: Microvenular hemangioma belongs to the group of acquired vascular tumors. It is important to differentiate such lesions because of their prognostic and nosologic consequences. We report a case of microvenular hemangioma. CASE REPORT: A 31 year-old man presented with a 3 cm erythematous and asymptomatic nodule of the abdomen, which had grown for 2 months. Histopathology showed the irregular dermal proliferation of small vessels, composed of capillaries and venules, without atypia. No relapse was noted 6 months after complete exeresis. DISCUSSION: Microvenular hemangioma is a recently described vascular tumor. The first three cases were reported in 1989, with the denomination of "microcapillar hemangioma". Twenty-one further cases have been reported since 1991. We discuss the typical clinical and histological characteristics of this lesion and present criteria permitting the differential diagnosis with other vascular neoplasms. Dermatologists should be aware of this lesion, notably for the differential diagnosis with early onset Kaposi's disease.