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The organic anion uptake and efflux transporters [organic anion-transporting polypeptide (OATP)1B1, OATP1B3 and multidrug resistance-associated protein (MRP)2 and MRP3] that mediate the transport of the hepatobiliary-specific contrast agent gadoxetate (Gd-EOB-DTPA) are direct or indirect targets of the farnesoid X receptor (FXR), a key regulator of bile acid and lipid homeostasis. In benign liver tumors, FXR expression and activation is not yet characterized. We investigated the expression and activation of FXR and its targets in hepatocellular adenoma (HCA) and focal nodular hyperplasia (FNH) and their correlation with Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI). Gd-EOB-DTPA MRI patterns were assessed by an expert radiologist. The intensity of the lesions on the hepatobiliary phase was correlated to mRNA expression levels of OATP1B1, OATP1B3, MRP2, MRP3, FXR, and small heterodimer partner (SHP) in fresh surgical specimens of patients with FNH or HCA subtypes. Normal and tumor sample pairs of 43 HCA and 14 FNH were included. All FNH (14/14) were hyperintense. Of the 34 HCA with available Gd-EOB-DTPA-enhanced MRI, 6 were hyperintense and 28 HCA were hypointense. OATP1B3 was downregulated in the hypointense tumors compared with normal surrounding liver tissue (2.77±3.59 vs. 12.9±15.6, P < 0.001). A significant positive correlation between FXR expression and activation and OATP1B3 expression level was found in the HCA cohort. SHP showed a trend toward downregulation in hypointense HCA. In conclusion, this study suggests that the MRI relative signal in HCA may reflect expression level and/or activity of SHP and FXR. Moreover, our data confirms the pivotal role of OATP1B3 in Gd-EOB-DTPA uptake in HCA. SIGNIFICANCE STATEMENT: FXR represents a valuable target for the treatment of liver disease and metabolic syndrome. Currently, two molecules, ursodeoxycholate and obeticholate, are approved for the treatment of primary biliary cirrhosis and cholestasis, with several compounds in clinical trials for the treatment of metabolic dysfunction-associated fatty liver disease. Because FXR expression and activation is associated with gadoxetate accumulation in HCA, an atypical gadoxetate-enhanced MRI pattern might arise in patients under FXR-targeted therapy, thereby complicating the differential diagnosis., (Copyright © 2024 by The American Society for Pharmacology and Experimental Therapeutics.)

Purpose and Context: Glypican-3 is often used to discriminate between neoplastic and nonneoplastic liver. In focal lesions, positivity may be considered suggestive of a malignancy such as hepatoblastoma. However, glypican-3 is also normally expressed in the immature liver. We present a series of 5 cases of focal nodular hyperplasia (FNH)-like lesions arising in very young patients with glypican-3 expression and highlight the challenges these lesions present in the differential diagnosis of hepatoblastoma., Methods: Cases were obtained from the files of 3 tertiary pediatric hospitals. Clinical data were obtained from the electronic medical record and histopathologic material including immunohistochemical stains were reviewed., Key Results: Patients were aged 2 weeks to 6 months with peak AFP levels ranging from 88.6 to 204,696 ng/mL. Microscopically, all were variably demarcated hepatocellular lesions with cords of hepatocytes, marked sinusoidal dilatation, and occasional fibrous bands and areas reminiscent of central scar with bile ducts. No significant cytologic atypia or increased mitotic activity were present. All showed glypican-3 expression and were negative for nuclear beta-catenin with intact reticulin framework., Conclusions: Our study highlights the pitfalls of evaluating focal liver lesions in infants when high AFP levels and glypican-3 expression may reflect immaturity rather than neoplasia.

The conclusive identity of Wnts regulating liver zonation (LZ) and regeneration (LR) remains unclear despite an undisputed role of β-catenin. Using single-cell analysis, we identified a conserved Wnt2 and Wnt9b expression in endothelial cells (ECs) in zone 3. EC-elimination of Wnt2 and Wnt9b led to both loss of β-catenin targets in zone 3, and re-appearance of zone 1 genes in zone 3, unraveling dynamicity in the LZ process. Impaired LR observed in the knockouts phenocopied models of defective hepatic Wnt signaling. Administration of a tetravalent antibody to activate Wnt signaling rescued LZ and LR in the knockouts and induced zone 3 gene expression and LR in controls. Administration of the agonist also promoted LR in acetaminophen overdose acute liver failure (ALF) fulfilling an unmet clinical need. Overall, we report an unequivocal role of EC-Wnt2 and Wnt9b in LZ and LR and show the role of Wnt activators as regenerative therapy for ALF., Competing Interests: Declaration of interests S.P.M. is a consultant for Surrozen. L.L.B., J.J.A., S.S.S., and S.A. are shareholders of AntlerA Therapeutics., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Nodular regenerative hyperplasia (NRH) can manifest as alternating parenchymal compression/expansion on hematoxylin and eosin (H&E) staining and as reticulin collapse/nodularity on reticulin staining. Histologic diagnosis can be challenging, especially when there is mild disease and on limited biopsy samples. We reviewed clinical and histologic parameters in a large series of NRH. We identified 60 liver specimens convincingly showing changes of NRH and reviewed them for clinical (age, sex, symptoms, lab values, portal hypertension [PHTN], NRH etiology) and histologic (inflammation, sinusoidal dilation, cholestasis, architectural change, portal vascular abnormalities, degree of changes on reticulin) parameters. The cases came from 28 women and 32 men (median age: 54 years). Most (55, 92%) were biopsies. Thirty patients were symptomatic. Forty-five cases showed mild NRH changes on reticulin; 24 of these (53%) showed them on H&E as well. Fifteen demonstrated well-developed changes on reticulin, which were always seen on H&E as well. Sinusoidal dilation was commonly observed in both of these subgroups (88% overall). Portal vascular abnormalities were seen in 33%. Well-developed NRH was diffuse more often than mild NRH (53% vs. 4%, P < 0.0001). Twenty-nine patients had clinically confirmed or likely PHTN. Of these, 21 showed mild and 8 showed well-developed NRH changes; only 3 had concomitant advanced fibrosis. Chemotherapy was the most frequent known cause of NRH; 30 patients lacked any definite etiology. NRH can be difficult to diagnose on biopsy, particularly since mild changes may be visible on reticulin but not H&E; even these patients can have PHTN. Additionally, NRH is often idiopathic, potentially lowering clinical and pathologic suspicion. Pathologists should have a low threshold for ordering reticulin stains, especially when a patient is known to have PHTN. Sinusoidal dilation, while nonspecific, commonly accompanies NRH., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Recent studies provide evidence that hepatocellular  adenomas  (HCAs) frequently take up gadoxetic acid (Gd-EOB) during the hepatobiliary phase (HBP). The purpose of our study was to investigate how to differentiate between Gd-EOB-enhancing HCAs and focal nodular hyperplasias (FNHs). We therefore retrospectively included 40 HCAs classified as HBP Gd-EOB-enhancing lesions from a sample of 100 histopathologically proven HCAs in 65 patients. These enhancing HCAs were matched retrospectively with 28 FNH lesions (standard of reference: surgical resection). Two readers (experienced abdominal radiologists blinded to clinical data) reviewed the images evaluating morphologic features and subjectively scoring Gd-EOB uptake (25-50%, 50-75% and 75-100%) for each lesion. Quantitative lesion-to-liver enhancement was measured in arterial, portal venous (PV), transitional and HBP. Additionally, multivariate regression analyses were performed., Results: Subjective scoring of intralesional Gd-EOB uptake showed the highest discriminatory accuracies (AUC: 0.848 (R#1); 0.920 (R#2)-p < 0.001) with significantly higher uptake scores assigned to FNHs (Cut-off: 75%-100%). Typical lobulation and presence of a central scar in FNH achieved an accuracy of 0.750 or higher in at least one reader (lobulation-AUC: 0.809 (R#1); 0.736 (R#2); central scar-AUC: 0.595 (R#1); 0.784 (R#2)). The multivariate regression emphasized the discriminatory power of the Gd-EOB scoring (p = 0.001/OR:22.15 (R#1) and p < 0.001/OR:99.12 (R#2). The lesion-to-liver ratio differed significantly between FNH and HCA in the PV phase and HBP (PV: 132.9 (FNH) and 110.2 (HCA), p = 0.048 and HBP: 110.3 (FNH) and 39.2 (HCA), p < 0.001)), while the difference was not significant in arterial and transitional contrast phases (p > 0.05)., Conclusion: Even in HBP-enhancing HCA, characterization of Gd-EOB uptake was found to provide the strongest discriminatory power in differentiating HCA from FNH. Furthermore, a lobulated appearance and a central scar are more frequently seen in FNH than in HCA.

Spectrins are a group of cytoskeletal proteins which participate in many important cellular functions. It has been suggested that loss of spectrin isoforms may be associated with tumorigenesis of lymphoma, leukemia, gastric cancer and hepatocellular carcinoma (HCC). We recently reported that βI spectrin expression was present in normal hepatocytes but lost in HCC cells, which suggested that spectrins may be helpful markers in diagnosis of HCC. In this study, using immunohistochemical staining, we further investigated the expression pattern of four spectrin isoforms (αII, βI-III) on different benign and malignant liver tumors including focal nodular hyperplasia (FNH), hepatic adenoma (HA), HCC, and cholangiocarcinoma (CC). The results revealed that βI spectrin was moderately to strongly positive in FNH and HA tissues, but was only weakly positive or lost in HCC cases and was weakly positive in all CC cases. In addition, the βIII spectrin, majority of which was moderately positive in both FNH and HA tissues, was mostly lost in poorly differentiated HCC but remained at least moderately positive in most CC cases. These results suggest that spectrins βI and βIII may be used to differentiate well differentiated HCC from FNH or HA, and poorly differentiated HCC from CC, respectively., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Purpose: The purpose of our study was to correlate the quantitative analysis of benign hepatocellular tumor uptake on delayed hepatobiliary phase (HBP) imaging with the quantitative level of OATP expression., Methods: This single-center retrospective study, which took place between September 2009 and March 2015, included 20 consecutive patients with a proven pathologic and immunohistochemical (IHC) diagnosis of FNH or HCA, including quantification of the OATP expression. The patients underwent Gd-BOPTA-enhancement MRI, including an HBP. The analysis of HBP uptake was performed using the liver-to-lesion contrast enhancement ratio (LLCER). Mean LLCER and OATP expressions were compared between FNH and HCA, and the expression of OATP was correlated with the LLCER value., Results: Of the 23 benign hepatocellular tumors, 9 (39%) were FNH and 14 (61%) were HCA, including 6 inflammatory, 2 HNF1a inactivated, 3 β-catenin-mutated and 3 unclassified HCAs. On HBP, 100% of the FNH appeared hyper- or isointense, and 79% of the adenomas appeared hypointense. The mean OATP expression of FNH (46.67 ± 26.58%) was significantly higher than that of HCA (22.14 ± 30.74%) (p = 0.0273), and the mean LLCER of FNH (10.66 ± 7.403%) was significantly higher than that of HCA (-13.5 ± 12.25%) (p < 0.0001). The mean LLCER of β-catenin-mutated HCA was significantly higher than that of other HCAs (p = 0.011). Significant correlation was found between the OATP expression and LLCER values (r = 0.661; p = 0.001)., Conclusion: In benign hepatocellular tumors, the quantitative analysis of hepatobiliary contrast agent uptake on HBP is correlated with the level of OATP expression and could be used as an imaging biomarker of the molecular background of HCA and FNH., Key Points: • Gd-BOPTA uptake on HBP correlates with the OATP level in benign hepatocellular tumors • FNH and β-catenin-mutated HCA showed an increased lesion-to-liver contrast enhancement ratio (LLCER) • Increased LLCER may be explained by activation of the Wnt β-catenin pathway.

Aims: To examine copper deposition in focal nodular hyperplasia (FNH) and inflammatory hepatocellular adenoma (IHA) and to determine if it can play a role in their differentiation., Methods: 28 FNHs and 19 IHAs from surgical resections showing typical morphological and immunohistochemical features were stained with rhodanine to evaluate for copper deposition. Histological features such as nodularity, fibrous bands, ductular proliferation, steatosis, ballooned hepatocytes and lymphocytic inflammation were also scored., Results: Copper deposition was detected in 96% (27/28) of FNHs and 37% (7/19) of IHAs, P<0.001. In all cases, copper was seen within the hepatocytes only around the pseudo-portal tracts or areas of fibrosis. Copper deposition in IHA was significantly associated with presence of lymphocytic inflammation (P=0.04) but not associated with features like nodularity, fibrous bands, ductular proliferation, ballooned hepatocytes and steatosis (P>0.05, for all). In FNH, the presence and degree of copper deposition was not significantly associated with any histological features (P>0.05, for all)., Conclusions: Copper deposition occurs more frequently in FNH (96%) than IHA (37%), P<0.001. However, the presence of copper alone cannot be used as a feature to differentiate between FNH and IHA., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Purpose: To identify the most reliable imaging features for differentiating hepatocellular carcinoma with paradoxical uptake on the hepatobiliary phase (HCC para ) from focal nodular hyperplasia (FNH)-like nodules using Gd-EOB-DTPA-enhanced MRI., Materials and Methods: This was a retrospective study. Twenty patients with HCC para and 21 patients with FNH-like nodules were included. The following MRI features were evaluated using 3.0 Tesla unit by two radiologists: signal intensity (SI) on T1-, T2-, and diffusion-weighted imaging (DWI), arterial enhancement pattern, washout appearance on the portal venous phase (PVP) and/or transitional phase (TP), uptake pattern on the hepatobiliary phase (HBP), "T2 scar," "EOB scar," and chemical shift on in- and out-of-phase images. Multivariate logistic regression analysis was performed to assess MRI features for prediction of HCC para ., Results: Compared with FNH-like nodules, HCC para had significantly more frequent heterogeneous T1 SI (P < 0.0001), T2 hyperintensity (P = 0.032), heterogeneous arterial enhancement (P < 0.0001), washout appearance on the PVP and/or TP (P < 0.0001), heterogeneous uptake on the HBP (P < 0.0001), absence of "EOB scar" (P < 0.0001), and hyperintensity on DWI (P = 0.004). Multivariate logistic regression analysis revealed washout appearance as the only independent imaging feature associated with HCC para (odds ratio, 7.019; P = 0.042). Washout appearance also showed the best diagnostic performance with a sensitivity of 90% and a specificity of 100%., Conclusion: Washout appearance on the PVP and/or TP is the most reliable imaging feature for differentiating HCC para from FNH-like nodules., Level of Evidence: 3 J. MAGN. RESON. IMAGING 2017;45:1599-1608., (© 2016 International Society for Magnetic Resonance in Medicine.)

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., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: The role of hormones in focal nodular hyperplasia (FNH) has been investigated with conflicting results., Objective: The aim of this study was to evaluate oestrogen and progesterone receptor immunohistochemical expression in FNH and surrounding normal liver (control material)., Methods: Biopsy materials from FNH and control tissue were investigated using an immunostainer. Receptor expression was graded as the proportion score (percentage of nuclear staining) and oestrogen receptor intensity score., Results: Study material included tissue from 11 resected FNH lesions and two core biopsies in 13 patients (two male). Twelve samples showed oestrogen receptor expression. The percentage of nuclear oestrogen receptor staining was <33% in eight FNH biopsies, 34-66% in two FNH biopsies, and >67% in both core biopsies. The better staining in core biopsies relates to limitations of the staining technique imposed by the fibrous nature of larger resected FNH. Control samples from surrounding tissue were available for nine of the resected specimens and all showed oestrogen receptor expression. Progesterone receptor expression was negligible in FNH and control samples., Conclusions: By contrast with previous studies, the majority of FNH and surrounding liver in this cohort demonstrated oestrogen receptor nuclear staining. The implications of this for continued oral contraceptive use in women of reproductive age with FNH remain uncertain given the lack of consistent reported growth response to oestrogen stimulation or withdrawal., (© 2015 International Hepato-Pancreato-Biliary Association.)

Context: The correct histologic diagnosis of mass lesions of the liver can be difficult, especially in biopsy samples. Reticulin, glypican-3, and glutamine synthetae are stains that can help distinguish hepatocellular carcinoma, hepatic adenoma, and focal nodular hyperplasia., Objective: To evaluate the utility of a triple stain of reticulin, glypican-3, and glutamine synthetae in distinguishing hepatocellular carcinoma, hepatic adenoma, and focal nodular hyperplasia., Design: Whole tissue sections and tissue microarrays were evaluated with a triple stain of reticulin, followed by glutamine synthetae (diaminobenzidine, brown chromogen) and glypican-3 (alkaline phosphatase, red chromogen). The 109 cases evaluated included whole tissue section hepatocellular carcinoma (n = 16), tissue microarray hepatocellular carcinoma (n = 19), whole tissue section hepatic adenoma (n = 15), tissue microarray hepatic adenoma (n = 13), whole tissue section focal nodular hyperplasia (n = 13; 12%), tissue microarray focal nodular hyperplasia (n = 13), as well as nonmalignant liver parenchyma adjacent to hepatocellular carcinoma (n = 20). All cases were scored for reticulin being intact or lost, positive or negative staining for glypican-3, and diffuse, maplike, perivenular, or negative staining for glutamine synthetae., Results: The combination of intact reticulin with either glypican-3 negativity or negative glutamine synthetae was 92% sensitive and 95% specific in the distinction of tissue microarray hepatic adenoma from hepatocellular carcinoma. For the distinction of tissue microarray focal nodular hyperplasia and hepatic adenoma, maplike glutamine synthetae was most useful and was 85% sensitive and 100% specific., Conclusions: The triple stain of reticulin, glypican-3, and glutamine synthetae is useful in the differentiation of hepatocellular carcinoma, hepatic adenoma, and focal nodular hyperplasia on biopsy specimens. Furthermore, this triple stain is advantageous to single stains and can help when aberrant staining patterns are observed.

Aims: To explore the immunohistochemical utility of proliferating cell nuclear antigen (PCNA), insulin-like growth factor 2 (IGF2) and clusterin in the distinction between malignant and benign liver nodular lesions., Methods: Immunohistochemical stains for PCNA, IGF2 and clusterin were performed on 284 liver nodular lesions, including 33 hepatocellular adenomas (HCA), 40 focal nodular hyperplasias (FNH), 77 large regenerative nodules (LRN) and 134 hepatocellular carcinomas (HCC)., Results: Strong and diffuse nuclear PCNA immunoreactivity was observed in 103 (77%) HCCs but in only 2 (6%) HCAs. None of the FNH and LRN cases showed a strong and diffuse staining pattern. All HCAs, 95% of FNHs and 92% of LRNs showed cytoplasmic IGF2 expression, with a strong staining observed in 70% of HCAs, 20% of FNHs and 30% of LRNs. This was in marked contrast to that observed in HCCs, where 66% of HCCs demonstrated a weak and focal/patchy immunostaining pattern and another 25% showed no detectable IGF2 immunoreactivity. In comparison with their adjacent non-lesional hepatocytes, 75% of HCCs showed decreased IGF2 expression. However, decreased IGF2 expression was not evident in HCAs, FNHs and LRNs. Cytoplasmic staining for clusterin was seen in both benign and malignant nodular lesions. However, an enhanced and exaggerated pericanalicular staining pattern was observed in 75% of HCCs, which was not demonstrated in HCAs, FNHs and LRNs., Conclusions: PCNA, IGF2 and clusterin show unique immunostaining characteristics in HCCs, which can be useful adjuncts to other currently available markers to aid in the distinction of HCC from benign liver nodular lesions., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Background & Aims: Nodular regenerative hyperplasia (NRH) is a rare liver disease characterized by small regenerative nodules without fibrosis and can cause portal hypertension. Aetiology and pathogenesis of NRH remain unclear. We have recently shown that Notch1 knockout induces NRH with portal hypertension through vascular remodelling in mice. The aim of this study was to analyse histological and clinical data of NRH patients and to explore if the endothelial pathways identified in our NRH mouse model are also regulated in human NRH., Methods: Patients were identified retrospectively from the pathology database. Clinical and laboratory patient data were retrieved. mRNA expression was measured in liver biopsies from a subset of NRH patients., Results: Diagnosis of NRH was confirmed in needle biopsies of 51 patients, including 31 patients with grade 1, 12 patients with grade 2 and 8 patients with grade 3 NRH. Grade 3 nodularity significantly correlated with the presence of portal hypertension: 50% of the patients with grade 3 NRH vs. 6.5% with grade 1 (P = 0.0105). mRNA expression analysis in liver biopsies from 14 NRH patients and in primary human sinusoidal endothelial cells revealed downregulation of identical genes as in the murine NRH model, which are implicated in vascular differentiation: Notch1, delta-like 4 (Dll4) and ephrinB2., Conclusions: In this large NRH needle biopsy cohort, we demonstrated that advanced nodularity correlates with presence of portal hypertension. Downregulation of the endothelial signalling pathways Dll4/Notch1 and ephrinB2/EphB4 supports the hypothesis that human NRH is caused by a sinusoidal injury providing first insights into the molecular pathogenesis of this liver condition., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The purpose of this study was to evaluate the gene expression of growth factors and growth factor receptors of primary hepatic masses, including hepatocellular carcinoma (HCC) and nodular hyperplasia (NH), in dogs. Quantitative real-time reverse transcriptase-polymerase chain reaction was performed to measure the expression of 18 genes in 18 HCCs, 10 NHs, 11 surrounding non-cancerous liver tissues and 4 healthy control liver tissues. Platelet-derived growth factor-B (PDGF-B), transforming growth factor-α, epidermal growth factor receptor, epidermal growth factor and hepatocyte growth factor were found to be differentially expressed in HCC compared with NH and the surrounding non-cancerous and healthy control liver tissues. PDGF-B is suggested to have the potential to become a valuable ancillary target for the treatment of canine HCC.

Objectives: To assess the range of hepatobiliary enhancement patterns of focal nodular hyperplasia (FNH) after gadoxetic-acid injection, and to correlate these patterns to specific histological features., Materials and Methods: FNH lesions, imaged with Gadoxetic-acid-enhanced MRI, with either typical imaging findings on T1, T2 and dynamic-enhanced sequences or histologically proven, were evaluated for hepatobiliary enhancement patterns and categorized as homogeneously hyperintense, inhomogeneously hyperintense, iso-intense, or hypo-intense-with-ring. Available histological specimens of FNHs (surgical resection or histological biopsy), were re-evaluated to correlate histological features with observed enhancement patterns., Results: 26 FNHs in 20 patients were included; histology was available in six lesions (four resections, two biopsies). The following distribution of enhancement patterns was observed: 10/26 homogeneously hyperintense, 4/26 inhomogeneously hyperintense, 5/26 iso-intense, 6/26 hypointense-with-ring, and 1/26 hypointense, but without enhancing ring. The following histological features associated with gadoxetic-acid uptake were identified: number and type of bile-ducts (pre-existent bile-ducts, proliferation, and metaplasia), extent of fibrosis, the presence of inflammation and extent of vascular proliferation., Conclusion: FNH lesions can be categorized into different hepatobiliary enhancement patterns on Gadoxetic-acid-enhanced MRI, which appear to be associated with histological differences in number and type of bile-ducts, and varying the presence of fibrous tissue, inflammation, and vascularization.

Recognizing hepatocellular nodules that cannot be classified as typical for hepatocellular carcinoma, hepatocellular adenoma, or focal nodular hyperplasia is important, especially in a patient with high risk for hepatocellular carcinoma. The authors report a case of a 53-year-old man with chronic hepatitis B, who was referred to the hospital with a liver mass found on routine imaging follow-up. Abdominal ultrasound revealed a 2.4-cm hypoechoic lesion. Contrast computed tomography showed homogeneous arterial enhancement and mild hyperdensity on portal venous phase images. Due to the high risk for hepatocellular carcinoma, the patient underwent laparoscopic left lateral segmentectomy that revealed a 2.2-cm poorly defined red-brown lesion. The nodule was diagnosed as a hypervascular/telangiectatic hyperplastic hepatocellular nodule based on histopathologic findings and immunostaining profile with negative glutamine synthetase, diffuse positive CD34 highlighting hyperplastic endothelial cells along the telangiectatic sinusoids and dilated vascular channels, and CK7 and CK19 reactive normal bile ducts within the lesion., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Phenotypic identification of focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) subtypes using immunohistochemical markers has been developed from their molecular characteristics. Our objective was to evaluate the sensitivity of these markers in the definitive diagnosis of these lesions by core needle biopsies. A total of 239 needle biopsies paired with their surgical resection specimen (group A) or without an associated resection specimen (group B) were reviewed. Using a step-by-step algorithm after standard staining, appropriate immunostaining analyses were performed to determine the certainty of diagnosis of FNH, HNF1α-inactivated HCA, inflammatory HCA, β-catenin-activated HCA, or unclassified HCA. The diagnosis of FNH was certain or probable on routine stains in 53% of needle biopsies of group A, whereas after glutamine synthetase staining, the diagnosis was certain in 86.7% as compared with 100% on the corresponding surgical specimen (P=0.04). In needle biopsies of group A, the diagnosis of HCA was certain on routine stains in 58.6% as compared with 94.3% on surgical specimens. After specific immunostaining, diagnosis was established on biopsies with 74.3% certainty, including all HCA subtypes, with similar distribution in surgical specimens. For each "certain diagnosis" paired diagnostic test (biopsy and surgical specimen), a positive correlation was observed (P<0.001). No significant difference was observed between groups A and B for FNH (P=0.714) or for HCA subtypes (P=0.750). Compared with surgical specimens, immunohistochemical analysis performed on biopsies allowed the discrimination of FNH from HCA and the identification of HCA subtypes with good performance.

Background & Aims: Notch signaling mediates embryonic vascular development and normal vascular remodeling; Notch1 knockout mice develop nodular regenerative hyperplasia (NRH). The pathogenesis of NRH is unclear, but has been associated with vascular injury in the liver sinusoids in clinical studies. We investigated the role of Notch1 signaling in liver sinusoidal endothelial cells (LSECs)., Methods: We studied MxCre Notch1(lox/lox) mice (conditional knockout mice without tissue-specific disruption of Notch1); mice with hepatocyte-specific knockout were created by crossing Notch1(lox/lox) with AlbCre(+/-) mice. Portal vein pressure was measured; morphology of the hepatic vasculature was assessed by histologic and scanning electron microscopy analyses. We performed functional and expression analyses of isolated liver cells., Results: MxCre-induced knockout of Notch1 led to NRH, in the absence of fibrosis, with a persistent increase in proliferation of LSECs. Notch1 deletion led to de-differentiation, vascular remodeling of the hepatic sinusoidal microvasculature, intussusceptive angiogenesis, and dysregulation of ephrinB2/EphB4 and endothelial tyrosine kinase. Time-course experiments revealed that vascular changes preceded node transformation. MxCre Notch1(lox/lox) mice had reduced endothelial fenestrae and developed portal hypertension and hepatic angiosarcoma over time. In contrast, mice with hepatocyte-specific disruption of Notch1 had a normal phenotype., Conclusions: Notch1 signaling is required for vascular homeostasis of hepatic sinusoids; it maintains quiescence and differentiation of LSECs in adult mice. Disruption of Notch1 signaling in LSECs leads to spontaneous formation of angiosarcoma, indicating its role as a tumor suppressor in the liver endothelium., (Copyright © 2012 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Aims: Patients with hepatocellular carcinoma (HCC) usually present with advanced disease and rarely qualify for curative therapy. Immunohistochemical markers that help to discriminate benign from malignant processes early, and that have prognostic significance, would be useful. Expression of the oncofetal protein insulin-like growth factor II mRNA-binding protein 3 (IMP3) in malignant cells of different tumour types correlates with reduced overall survival., Methods and Results: Tissue microarrays (TMAs) containing 55 normal liver samples, 365 HCCs (122 with corresponding non-tumorous liver), 10 hepatocellular adenomas, 13 focal nodular hyperplasias and nine dysplastic nodules from western European patients were stained for IMP3. IMP3 was analysed in 61 core needle biopsies and findings were compared to glypican-3 and CD34. HCCs in TMAs were strongly positive for IMP3 in 18.4% of cases compared to absent expression in normal and non-tumorous liver tissue and benign liver tumours. Patients with IMP3 expression in HCCs showed significantly poorer overall survival in multivariate analysis (P = 0.044). Of the 61 core needle biopsies analysed, 32 (52.5%) of the HCCs were IMP3-positive., Conclusions: In core needle biopsies, IMP3 expression seems to be of limited use as a single marker for the diagnosis of HCC, given a sensitivity of 52%, but it may be helpful in combination with other markers., (© 2011 Blackwell Publishing Limited.)

Serum alpha-fetoprotein (AFP), the main serum marker of hepatocellular carcinoma, may increase in some benign conditions involving the liver but is usually within normal values in focal nodular hyperplasia (FNH) in adults. We present a case of a FNH associated with serum AFP increase, and in which both the lesion and the non-lesional adjacent liver showed AFP-positive immunostained areas. Moreover, only one case of FNH with AFP-positive immunostaining has been previously reported. In addition, our case of FNH is remarkable as it displayed some morphological and immunophenotypical features of progenitor cells. The serum AFP levels rose after liver resection and progressively returned to the preoperative high values. These findings are concordant with the hypothesis that FNH is a regenerative process, and suggest that regenerative areas in the liver might be the source of AFP production., (© 2011 The Authors. Pathology International © 2011 Japanese Society of Pathology and Blackwell Publishing Asia Pty Ltd.)

Wnt/β-catenin signaling is known for its role in embryogenesis as well as carcinogenesis. In the liver, it plays many critical roles during hepatic development and regeneration, and its dysregulation is evident in aberrant hepatic growth during various liver tumors. Its chief cellular roles in the liver include regulation of processes of cell proliferation, apoptosis, oxidative stress and differentiation, which in turn contributes to hepatic growth, zonation, xenobiotic metabolism and other metabolic processes inherent to the liver. Most of these functions of the Wnt/β-catenin signaling are dictated through the highly temporal and tissue-specific or non-specific transcriptional targets of the pathway. In addition, some of the critical functions such as cell-cell adhesion and perhaps maintenance of various junctions that are critical from an epithelial cell biology perspective are also a function of β-catenin, which is the central component of the canonical Wnt pathway. Various animal models and clinical studies have demonstrated the spectra of Wnt/β-catenin signaling in liver health and disease. Thus therapeutic modulation of this pathway for improved hepatic health is inevitable in the future. The current review discusses the advances in our understanding of the Wnt/β-catenin signaling in liver physiology and pathology especially in hepatic metabolism and various tumors in adult liver and goes on to extrapolate the pre-clinical significance and possible translational implications of such findings., (Copyright © 2009 Elsevier Ltd. All rights reserved.)

The aim of this pilot study was to evaluate the use of PET/CT with (18)F-fluorocholine in the differentiation of hepatocellular adenoma (HCA) from focal nodular hyperplasia (FNH). Patients with liver lesions larger than 2 cm suspicious for HCA or FNH were prospectively included. All patients underwent PET/CT with (18)F-fluorocholine and histopathological diagnosis was obtained by either liver biopsy or surgery. The ratios between the maximum standardized uptake value (SUV) of the lesion and the mean SUV of normal liver parenchyma were calculated and a receiver operating characteristic (ROC) curve analysis was performed. Ten patients with FNH and 11 with HCA were included. The mean SUV ratio was 1.68±0.29 (±SD) for FNH and 0.88±0.18 for HCA (p<0.001). An SUV ratio cut-off value between 1.12 and 1.22 differentiated patients with FNH from those with HCA with 100% sensitivity and 100% specificity. This pilot study showed that PET/CT with (18)F-fluorocholine can differentiate HCA from FNH.

In this review, the authors focus on the use of immunohistochemistry to characterize the different types and subtypes of benign hepatocellular nodules. They describe the classical and currently accepted features leading to the easy and formal diagnosis of focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA). In addition, they report some atypical features and difficulties in the interpretation of section staining analyses, which represent important parameters for pathologists. A significant contribution of molecular biology to the characterization of FNH has been to reclassify some cases of FNH as inflammatory HCA. Furthermore, the pattern of overexpression of glutamine synthetase (GS), a target gene of β-catenin has been successfully used to identify FNH by immunohistochemistry. Molecular approaches have demonstrated that HCA is a heterogeneous entity. Genotype classification of HCA has allowed the identification of three subtypes: HNF1A-mutated HCA (H-HCA) in 35% of cases, β-catenin-mutated HCA (b-HCA) in 10%, and inflammatory HCA (IHCA) in 55%. Following molecular data, the diagnosis of H-HCA relies on the lack of liver fatty acid binding protein (LFABP) immunostaining. The diagnosis of b-HCA is straightforward when GS is strongly and diffusely expressed by lesional hepatocytes, and is accompanied by nuclear β-catenin immunoreactivity. In IHCA, serum amyloid protein and C- reactive protein are strongly and usually diffusely expressed by tumoral hepatocytes with a sharp limit with the surrounding nontumoral liver. IHCA can also be β-catenin activated (10%). Due to the strong association of b-HCA with hepatocellular carcinoma transformation, the identification of this HCA subtype is extremely important., (© Thieme Medical Publishers.)

Objective: To study the expression and significance of GPC3, CD10 and CD34 in hepatocellular carcinoma (HCC), dysplastic nodules (DN), cirrhotic regenerative nodules (CRN), focal nodular hyperplasia (FNH) and hepatocellular adenoma (HA)., Methods: Immunohistochemical study for GPC3, CD10, CD34 and AFP was performed on 80 cases of HCC (30 cases of well-differentiated HCC and 50 cases of advanced HCC), 30 cases of DN (18 cases of high-grade DN and 12 cases of low-grade DN), 36 cases of CRN, 20 cases of FNH and 20 cases of HA., Results: (1) The positive expression rate of GPC3 was 92% (46/50) in advanced HCC, 66.7% (20/30) in well-differentiated HCC, 2/18 in high-grade DN, and 0 in low-grade DN, CRN, FNH and HA. The expression rate of GPC3 in well-differentiated HCC was lower than that in advanced HCC and higher than that in high-grade DN (P < 0.05). (2) The negative expression rate of CD10 was 78% (39/50) in advanced HCC, 43.3% (13/30) in well-differentiated HCC, 20% (4/20 and 4/20) in both FNH and HA, 2.8% (1/36) in CRN and 0 in both high-grade DN and low-grade DN. The occurrence of CD10-strongly positive cells was 2% (1/50) in advanced HCC, 16.7% (5/30) in well-differentiated HCC, 15/18 in high-grade DN, 11/12 in low-grade DN, 80.6% (29/36) in CRN and 60% (12/20 and 12/20) in both FNH and HA. The positive expression rate of CD10 in well-differentiated HCC was higher than that in advanced HCC and lower than that in high-grade DN, low-grade DN, CRN, FNH and HA (P < 0.05). (3) The positive expression rates of CD34 in advanced HCC and well-differentiated HCC ranged from 25% to 100% [and strongly positive in 76% (38/50) and 70% (21/30), respectively]. The rates in high-grade DN and low-grade DN ranged from 5% to 25% (and weakly positive in 16/18 and 10/12, respectively). In CRN, the rate ranged from 0 to 5% [and weakly positive in 27.8% (10/36)]. In FNH and HA, the positive rates ranged from 25% to 50%. The positive expression rate of CD34 in well-differentiated HCC was significantly higher than that in high-grade DN, low-grade DN, CRN, FNH and HA (P < 0.05). (4) The positive expression rate of AFP was 44% (22/50) in advanced HCC, 20% (6/30) in well-differentiated HCC, no expression in DN, LCN, LCN, FNH and HA. The positive expression rate of AFP in well-differentiated HCC was lower than that in advanced HCC and higher than that in LCN, FNH and HA. The different expression had statistical significance (P < 0.05)., Conclusions: GPC3 is a relatively sensitive and specific marker in pathologic diagnosis of HCC. When coupled with immunohistochemical results of CD34, CD10 and AFP, GPC3 is useful in differentiating HCC from DN, LCN, FNH and HA.

We report a patient with alcoholic liver cirrhosis who had a 15 mm focal nodular hyperplasia (FNH)-like nodule in the liver. This FNH-like nodule was diagnosed as hepatocellular carcinoma (HCC) mainly based on hypervascularity during the hepatic arterial phase, washout pattern during the equilibrium phase and low signal intensity during the hepatobiliary phase in gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI; it was surgically resected. Its histology exhibited hepatocyte hyperplasia, fibrous septa containing unpaired small arteries accompanied by reactive bile ductules, remarkable iron deposits and sinusoidal capillarization, and was compatible with the diagnosis of an FNH-like nodule. When we analyzed the images of the present nodule retrospectively, low signal intensity on in-phase and isosignal intensity on opposed-phase T1-weighted MRI may have reflected iron deposits in the FNH-like nodule. In addition, a low signal intensity on T2-weighted MRI and no detection in diffusion-weighted MRI may help in distinguishing FNH-like nodules from HCC, since these image findings are inconsistent with typical HCC. Immunohistochemical analysis revealed a markedly reduced expression of organic anion transporter (OATP) 1B3 in this nodule, which implied decreased Gd-EOB-DTPA uptake by hepatocytes and accounted for the low signal intensity during the hepatobiliary phase on Gd-EOB-DTPA-enhanced MRI. To the best of our knowledge this is the first report in which an FNH-like nodule was assessed for OATP1B3 expression.

In this review, we focus on the interest of immunohistochemistry first, to differentiate the two types of benign hepatocellular nodules: focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) and second, to recognize the different subtypes of HCA: HNF1α inactivated HCA, β-catenin activated HCA and inflammatory HCA. This pathomolecular classication followed the study of genotype/phenotype correlations which led to the identification of immunohistochemical data characteristic of each subgroup. Immunohistochemical characteristics described on resected specimen are suitable on biopies of these tumors, facilitating their diagnosis and therefore allowing a better management of the patients., (Copyright © 2010 Elsevier Masson SAS. All rights reserved.)

Context: Despite the recognition of the follicular variant of papillary carcinoma of the thyroid (FVPTC) for over 50 years, reproducibility of this diagnostic category has remained poor. Architectural features have been of variable utility as some FVPTC seem encapsulated, whereas others are multifocal and may be confused with nodular hyperplasia. Nuclear features are important for diagnosis of FVPTC, but some authors have discounted the utility of nuclear grooves and inclusions. More recently, BRAF and HBME-1 (Human Bone Marrow Endothelial Cell-1) have been suggested as markers for FVPTC., Objective: To investigate the frequency of BRAF mutations and HBME-1 immunopositivity, in a series of FVPTCs in which the diagnosis was established by 100% consensus among a panel of 6 surgical pathologists., Design: Twenty-eight specimens with an original diagnosis of FVPTC and 10 cases with other diagnoses were obtained from the surgical pathology files of the University of Utah School of Medicine. All specimens were independently reviewed by 6 surgical pathologists. Tissue blocks were analyzed for BRAF exon 15 mutations and HMBE-1 expression., Results: Complete agreement among pathologists for the diagnosis of FVPTC was obtained in 28.6% (8/28) of cases originally diagnosed as FVPTC. Mutations in BRAF exon 15 were found in 25% (2/8) of cases with a 100% consensus diagnosis of FVPTC and 32% (6/19) of cases unanimously diagnosed as a type of papillary carcinoma (classic or follicular variant). HBME-1 was expressed in 87.5% (7/8) of lesions with a 100% consensus diagnosis of FVPTC and 84.2% (16/19) of lesions with a unanimous diagnosis of a type of papillary carcinoma of the thyroid (classic or follicular variant)., Conclusions: Interobserver agreement for the diagnosis of FVPTC is poor and testing for the BRAF mutation is only marginally helpful because a minority of FVPTCs possess the mutation. HBME-1 expression when coupled with a BRAF mutation, results in 100% specificity but low sensitivity for the presence of papillary carcinoma of the thyroid including the follicular variant.

Heparan sulfate (HS), due to its ability to interact with a multitude of HS-binding factors, is involved in a variety of physiological and pathological processes. Remarkably diverse fine structure of HS, shaped by non-exhaustive enzymatic modifications, influences the interaction of HS with its partners. Here we characterized the HS profile of normal human and rat liver, as well as alterations of HS related to liver fibrogenesis and carcinogenesis, by using sulfation-specific antibodies. The HS immunopattern was compared with the immunolocalization of selected HS proteoglycans. HS samples from normal liver and hepatocellular carcinoma (HCC) were subjected to disaccharide analysis. Expression changes of nine HS-modifying enzymes in human fibrogenic diseases and HCC were measured by quantitative RT-PCR. Increased abundance and altered immunolocalization of HS was paralleled by elevated mRNA levels of HS-modifying enzymes in the diseased liver. The strong immunoreactivity of the normal liver for 3-O-sulfated epitope further increased with disease, along with upregulation of 3-OST-1. Modest 6-O-undersulfation of HCC HS is probably explained by Sulf overexpression. Our results may prompt further investigation of the role of highly 3-O-sulfated and partially 6-O-desulfated HS in pathological processes such as hepatitis virus entry and aberrant growth factor signaling in fibrogenic liver diseases and HCC.

Aims: To study the relevance of periostin, known to be involved in epithelial-mesenchymal transition (EMT), in hepatocellular and bile duct cancer., Methods and Results: Immunohistochemical periostin expression was semiquantitatively analysed in normal liver tissue (n = 20), hepatocellular carcinoma (HCC; n = 91), liver-cell adenoma (n = 9), focal nodular hyperplasia (n = 13) and bile duct carcinomas (BDC; n = 116) using tissue microarrays. Normal bile ducts, gallbladder epithelium and hepatocytes showed weak cytoplasmic periostin expression. In HCC, there was strong epithelial periostin expression in 19/91 (20.9%) and strong stromal periostin expression in 10/91 cases (11%). Epithelial expression in tumour cells was significantly associated with a higher tumour grade (P < 0.05) and hepatitis B virus infection (P = 0.007). Importantly, there was no strong periostin expression in benign liver tumours. Strong stromal periostin expression was detected in 78/116 (67.2%) BDC and strong epithelial expression in 39/116 (33.6%) BDC. pT stage, differentiation grade and proliferation rate in primary BDC were independent of periostin expression. Epithelial periostin expression was associated with reduced overall survival on univariate and multivariate analysis., Conclusions: The EMT protein periostin is expressed in the stroma and epithelium of a subset of BDC and HCC. Epithelial periostin expression is a marker for malignant transformation of hepatocytes and a novel prognostic marker in BDC.

Background: Inflammatory hepatocellular adenoma (IHCA) defines a subgroup of hepatocellular adenomas characterized by the expression of members of the acute-phase inflammatory response [(serum amyloid A protein (SAA) and C-reactive protein (CRP)]. IHCA are unique or multiple as defined by the presence of several nodule(s) larger than 10 mm using both imaging and macroscopic observation. Frequently, additional micronodules (<10 mm), previously undetected by imaging, can be observed in resected specimens., Aims: To analyse micronodules in multiple (group 1, nine patients) and single (group 2, eight patients) IHCA cases, immunohistochemistry using SAA and CRP antibodies was performed on all nodules detected under macroscopic examination as well as on surrounding tissue with no visible nodules., Results: Nodules of different sizes (>5 < or = 10 mm, > or = 1 < or = 5 mm) were found in group 1, whereas only rare nodules in the mm range were found in group 2. Micronodules shared the characteristics of large nodules, which justified surgery such as inflammatory infiltrates, abnormal arteries, sinusoidal dilatation or peliosis. However, the number of these characteristics was proportional to the size of the nodules., Conclusion: This study demonstrates that the real number of IHCA is greater than that predicted from imaging-based analyses. In addition, we show that patients with more than one nodule present a greater chance to display more and larger undetected micronodules than patients with a single nodule.

Unlabelled: Hepatocellular carcinomas (HCCs) and bile duct carcinomas (BDCs) have a poor prognosis. Therefore, surveillance strategies including sensitive and specific serum markers for early detection are needed. Recently, Golgi Phosphoprotein 2 (GOLPH2) has been proposed as a serum marker for HCC, but GOLPH2 expression data in liver tissues was not available. Using tissue microarrays and immunohistochemistry, we semiquantitatively analyzed GOLPH2 protein expression in patients with HCC (n = 170), benign liver tumors (n = 22), BDC (n = 114) and normal liver tissue (n = 105). A newly designed sandwich enzyme-linked immunoassay (ELISA) was used to analyze GOLPH2 levels in the sera of patients with HCC (n = 62), hepatitis C virus (HCV) (n = 29), BDC (n = 10), and healthy control persons (n = 12). By immunohistochemistry 121/170 (71%) of HCC showed strong GOLPH2 expression, which was significantly associated with a higher tumor grade (P = 0.01). A total of 97/114 (85%) BDCs showed a strong GOLPH2 expression which proved to be an independent prognostic factor for overall survival (P < 0.05). Serum levels of GOLPH2 measured by ELISA were significantly elevated in patients with HCC with underlying HCV infection (median 18 mg/L, P < 0.05) and patients with BDC (median = 14.5 mg/L, P < 0.01) in comparison to healthy controls (median 4 mg/L)., Conclusion: GOLPH2 protein is highly expressed in tissues of HCC and BDC. GOLPH2 protein levels are detectable and quantifiable in sera by ELISA. In patients with hepatitis C, serial ELISA measurements in the course of the disease appear to be a promising complementary serum marker in the surveillance of HCC. GOLPH2 should be further evaluated as a serum tumor marker in BDC on a larger scale.

Focal nodular hyperplasia (FNH) of the liver is considered to develop as a hyperplastic response to a preexisting vascular abnormality. From the pathogenic point of view, we studied histological alterations in the extranodular background liver tissue of FNH (FNH-bg-liver). We compared ten FNH-bg-livers with ten non-FNH cases (non-FNH-liver) and found small uniform nodule formations with ring-like siderosis in the FNH-bg-livers (4/7, 57%) but not in the non-FNH-livers. Abnormal small arteries not accompanied by portal tracts were observed in six of six FNH-bg-livers for which immunohistochemical study was available, while this was observed in only three of the ten non-FNH-livers. CD34-positive sinusoids around the portal tracts were observed in only the FNH-bg-livers (3/6, 50%). Further, two of ten FNH-bg-livers had ectopic pancreatic tissue. Ring-like siderosis, abnormal small arteries, CD34-positive sinusoids, and ectopic pancreatic tissue were characteristic in the extranodular background liver tissue in cases of FNH.

Focal nodular hyperplasia of the liver is typically accompanied by a central scar, but cases that lack the central scar are occasionally encountered. This study was performed to clarify the mechanism of the central scar formation in focal nodular hyperplasia. Immunohistochemical analysis was performed for liver sections of focal nodular hyperplasia with and without a central scar. For comparison, liver specimens of focal nodular hyperplasia-like nodules and nodular regenerative hyperplasia were used. Immunostaining showed that activated hepatic stellate cells, as determined by alpha-smooth muscle actin expression, were invariably observed in all cases of focal nodular hyperplasia with a central scar, whereas focal nodular hyperplasia without a central scar and nodular regenerative hyperplasia lacked hepatic stellate cell activation. Hepatic stellate cell activation in focal nodular hyperplasia with a central scar was accompanied by the expression of 8-hydroxy-2'-deoxyguanosine and inducible nitric oxide synthase in the liver. Expression of 8-hydroxy-2'-deoxyguanosine and inducible nitric oxide synthase was rarely seen in focal nodular hyperplasia without a central scar, focal nodular hyperplasia-like nodules, or nodular regenerative hyperplasia. Overexpression of vascular endothelial growth factor was also observed in focal nodular hyperplasia with a central scar. These results suggest that the central part of focal nodular hyperplasia suffers from hyperoxic conditions due to arterial hyperperfusion; and the resultant oxidative stress may activate hepatic stellate cells, leading to central scar formation. In addition, vascular endothelial growth factor may contribute to the proliferation of abnormal vessels as an angiogenic inducer.

Context: Histopathologic distinction between hepatocellular carcinoma (HCC) and benign hepatocellular mass lesions, particularly hepatocellular adenoma, can sometimes be challenging. The currently available ancillary tools are suboptimal in terms of sensitivity and specificity., Objective: To further characterize the diagnostic value of glypican-3 (GPC3), a cell surface proteoglycan that has recently been shown to be overexpressed in HCC, in the distinction between HCC and benign hepatocellular mass lesions., Design: A total of 221 surgically resected liver specimens were subjected to immunohistochemical staining using a monoclonal antibody specific for GPC3. These included 111 HCCs, 48 hepatocellular adenomas, 30 focal nodular hyperplasias, and 32 large regenerative nodules in the background of cirrhosis., Results: Cytoplasmic, membranous, and canalicular staining for GPC3 was detected in 84 (75.7%) of the 111 HCCs, among which, 61 (72.6%) of the 84 cases exhibited diffuse immunoreactivity. In contrast, none of the 110 cases of hepatocellular adenoma, focal nodular hyperplasia, and large regenerative nodule showed detectable GPC3 staining. Focal GPC3 immunoreactivity was detected in cirrhotic nodules in 11 (16.4%) of 67 HCC cases with a cirrhotic background, but no background staining was observed in the remaining 44 HCCs without cirrhosis. GPC3 expression in HCCs did not correlate with the size, differentiation, or stage of the tumors; the presence or absence of cirrhotic background; or the underlying etiologies., Conclusions: GPC3 is a specific immunomarker for HCC that can be used to distinguish HCC from benign hepatocellular mass lesions, particularly hepatocellular adenoma. However, the diagnosis of HCC should not rely entirely on positive GPC3 immunostaining because focal immunoreactivity can be detected in a small subset of cirrhotic nodules. In addition, GPC3 expression in HCC can also be focal, and thus, the lack of GPC3 staining does not exclude the diagnosis of HCC.

Differentiating focal nodular hyperplasia from hepatic adenoma can be challenging. Cytokeratin 7, neuronal cell adhesion molecule, and cytokeratin 19 are differentially expressed in hepatocytes, biliary epithelium, and possibly hepatic progenitor/stem cells. CD34 is known to have altered expression patterns in the hepatic endothelium in conditions associated with abnormal perfusion and in hepatocellular carcinoma. The purpose of this study was to examine the expression pattern of these markers in focal nodular hyperplasia and hepatic adenoma and assess their diagnostic use. Ten resection specimens each of hepatic adenoma and focal nodular hyperplasia (including a case of telangiectatic focal nodular hyperplasia) were selected for the study. Immunohistochemical analysis was performed using antibodies against cytokeratin 7, cytokeratin 19, neuronal cell adhesion molecule, and CD34 on formalin-fixed, paraffin-embedded sections from each case. The staining patterns and intensity for each marker were analyzed. In hepatic adenoma, the cytokeratin 7 stain revealed strong positivity in hepatocytes in patches, with a gradual decrease in the staining intensity as the cells differentiated towards mature hepatocytes. Although bile ducts were typically absent in hepatic adenoma, occasional ductules could be identified with cytokeratin 7 stain. In focal nodular hyperplasia, cytokeratin 7 showed strong staining of the biliary epithelium within the fibrous septa and staining of the peripheral hepatocytes of most lobules that was focal and weaker than hepatic adenoma. Cytokeratin 19 and neuronal cell adhesion molecule showed patchy and moderate staining in the biliary epithelium of the ductules in focal nodular hyperplasia. While in the hepatic adenoma, cytokeratin 19 showed only rare positivity in occasional cells within ductules, and neuronal cell adhesion molecule marked occasional isolated cells in the lesion. CD34 showed staining of sinusoids in the inflow areas (periportal areas) in both focal nodular hyperplasia and hepatic adenoma. One case of telangiectatic focal nodular hyperplasia revealed both hepatic adenoma-like and focal nodular hyperplasia-like staining patterns. Distinct cytokeratin 7, cytokeratin 19, and neuronal cell adhesion molecule staining patterns are seen in hepatic adenoma and focal nodular hyperplasia possibly suggest activation of different subsets of hepatic progenitor/stem cell and can be diagnostically useful.

Background/aims: Focal nodular hyperplasias (FNHs) are benign liver lesions considered to be a hyperplastic response to increased blood flow in normal liver. In contrast, FNH-like lesions/nodules occur in cirrhotic liver but share similar histopathological features. We conducted a transcriptome analysis to identify biological pathways deregulated in FNH., Methods: Gene expression profiles obtained in FNH and normal livers were compared. Differentially-expressed genes were validated using quantitative-RT-PCR in 70 benign liver tumors including FNH-like lesions., Results: Among the deregulated genes in FNHs, 19 displayed physiological restricted distribution in the normal liver. All six perivenous genes were up-regulated in FNH, whereas 13 periportal genes were down-regulated. Almost all these genes are known to be regulated by beta-catenin. Glutamine synthetase was markedly overexpressed in anastomosed areas usually centered on visible veins. Moreover, activated hypophosphorylated beta-catenin protein accumulated in FNH in the absence of activating mutations. These results suggest the zonated activation of the beta-catenin pathway in FNH, whereas the other benign hepatocellular tumors, including FNH-like lesions, demonstrated an entirely different pattern of beta-catenin expression., Conclusions: In FNH, increased activation of the beta-catenin pathway was found restricted to enlarged perivenous areas. FNH-like nodules may have a different pathogenetic origin.

Focal nodular hyperplasia (FNH) is rare in pediatric liver tumor. To investigate the experience in the appropriate management of pediatric FNH, the records of consecutive children who were managed at our institute from 2000 to 2007were reviewed for FNH. There were four males and nine females whose ages ranged from 26 months to 18 years with a mean of 11.7 years. FNH in most children was detected by medical examination for abdominal pain (61.5%) or other symptoms. All the 13 pediatric patients underwent liver resection. There was no operative death or postoperative complications. The children were regularly followed up ranging from 2 to 85 months and they were healthy without recurrence. For pediatric FNH patients with clinical symptoms or indefinite diagnosis, it is suggested that active surgical treatment by hepatectomy should be performed.

Objective: To study the expression of nucleophosmin/B23 (B23) in tumor cells of hepatocellular carcinoma (HCC) and its clinicopathologic significance., Methods: Mouse monoclonal antibodies against B23 were raised by recombinant protein and hybridoma technology. Immunohistochemical study for B23 was performed on 103 cases of HCC, 12 cases of focal nodular hyperplasia and 17 cases of native liver tissue adjacent to hepatic hemangioma. Fresh specimens from 10 cases of HCC and the adjacent liver tissue were also collected for reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analysis. The expression of B23 was analyzed and compared with that of proliferative cell nuclear antigen (PCNA) in these specimens., Results: RT-PCR and Western blot analysis showed that B23 expression in HCC was higher than that in adjacent liver tissue. Statistically significant difference in expressions of B23 and PCNA were also noted in the four groups studied (P < 0.01). B23 and PCNA expressions in HCC were higher than those in the other three groups (P < 0.01). There was also a statistically significant correlation between B23 and PCNA expressions amongst the four groups (r = 0.4769, P < 0.01). Besides, B23 expression in HCC correlated with pathologic tumor grading, serum alpha-fetal protein levels and cirrhotic status (P < 0.05)., Conclusions: B23 expression in HCC was significantly higher than that in liver tissues with non-malignant diseases. B23 may be used as a marker for neoplastic changes in liver cells and thus has potential clinicopathologic application.

Nodular lymphoid lesion (NLL) of the liver is a rare but unique entity and has also been termed reactive lymphoid hyperplasia of the liver. We describe the histological, immunohistochemical and molecular biologic findings of a case with NLL and two other tumors of the liver. The nodular lymphoid mass found in the liver was composed of heterogeneous small lymphocytes forming reactive follicles. Plasma cells, few immunoblasts, centroblasts, few macrophages, epithelioid cells, and giant cells were seen. The lymphoid infiltrate displaced the adjacent hepatic parenchyma. By immunohistochemistry and molecular studies, the lymphocytes were found to be polyclonal. The diagnosis of NLL was made. In addition to NLL, focal nodular hyperplasia and hemangioma were detected. The discrimination of NLL from primary hepatic malignant non-Hodgkin's lymphoma of mucosa-associated lymphoid tissue-type may pose diagnostic difficulties and may require the use of immunohistochemical and molecular techniques. The simultaneous occurrence of NLL with focal nodular hyperplasia and hemangioma in the liver has not been described before.

Focal nodular hyperplasia (FNH) of the liver can be a difficult diagnosis to establish in limited diagnostic samples such as a needle-core tissue biopsy, especially for pathologists with limited experience with the lesion. To characterize the features that can be used to make the diagnosis, we reviewed and analyzed the clinicopathologic features of 100 consecutive cases submitted for consultation in which we were confident of the diagnosis of FNH in needle biopsy material. A diagnosis of FNH was correctly made by the contributing pathologist in 24 of the 100 referred cases. Most of the patients (81%) were women of childbearing age with a mean age of 36.75 +/- 9.82 years. Most of the patients (70%) were asymptomatic at diagnosis. The most consistent diagnostic histological feature of FNH in needle biopsy was the presence of ductular reaction with varied intensity at the junction of the fibrous septa with the hepatocellular component, which was present in all 100 cases. Thick abnormal arteries were seen in all but 2 cases (n = 98). Features of chronic cholestasis with cholate stasis and accumulation of copper (demonstrable by the rhodanine stain) and copper-binding protein (demonstrable with the Victoria blue stain) were nearly as common (n = 94). A confident diagnosis of FNH can be made with a needle biopsy, especially if the biopsy is known to come from a mass, and the lesion contains characteristic fibrosis with ductules at the interface between hepatocytes and the fibrous region, prominent arteries, and benign hepatocytes with features of chronic cholestasis.

Background/aims: Little information is available about the patterns of endothelial cell differentiation observed in hepatocellular adenomas. We therefore aimed to analyze the endothelial cell immunophenotype in a large series of these tumors and evaluate its possible diagnostic relevance., Methods: The expression of continuous and sinusoidal endothelial cell markers and of extracellular matrix proteins was analyzed by immunoperoxidase in 56 adenomas, as compared with 30 cases of focal nodular hyperplasia (FNH), 2 cases of telangiectatic FNH and 40 cases of hepatocellular carcinoma (HCC)., Results: Twenty-eight adenomas (50%) presented a sinusoidal pattern of endothelial cell differentiation, characterized by the expression of specific sinusoidal endothelial cell markers and the presence of a subendothelial matrix resembling the normal perisinusoidal matrix. Eleven tumors (19.5%) presented a continuous pattern of endothelial cell differentiation. Seventeen tumors (30.5%) showed a mixed pattern. Twenty-eight FNH presented a sinusoidal pattern of endothelial cell differentiation; all HCC presented a continuous pattern of endothelial cell differentiation., Conclusions: In hepatocellular adenomas, intra-tumoral vessels usually present a sinusoidal pattern of endothelial cell differentiation. However, the vascular phenotypic heterogeneity observed in our study questions the potential relevance of endothelial cell immunophenotyping for the differential diagnosis between hepatocellular adenomas and well differentiated HCC.

Macroscopic and histological characteristics of focal nodular hyperplasia (FNH) of the liver are presented. Characteristic microscopic signs are the presence of numerous septs with many biliary ducts. Hepatocytes with diploid number of chromosomes show negative Ki-67 and p53. Ultrastructure of hepatocytes in FNH does not differ from that of normal cells of the liver.

Background & Aims: "Telangiectatic focal nodular hyperplasia" designate atypical lesions considered as variants of focal nodular hyperplasia (FNH). However, because "telangiectatic FNH" share several morphologic patterns with hepatocellular adenomas, classification of such lesions deserve further clarification. Therefore, the aim of the present study was to reconsider the classification of telangiectatic FNH with the help of a molecular approach., Methods: Ten telangiectatic FNH, 6 typical FNH, and 6 hepatocellular adenomas were studied. DNA, RNA, and protein from each lesion were extracted. Clonality was assessed by the study of the X chromosome inactivation pattern (HUMARA assay). Angiopoietin (ANGPT-1 and ANGPT-2) mRNA, genes the expression of which is typically modified in FNH, were quantified by a real-time RT-PCR procedure. Protein profiles were analyzed by SELDI-TOF PROTEINCHIP (Cyphergen Biosystem, Inc., Fremont, CA) technology., Results: Although all informative cases of FNH (5 of 6) and hepatocellular adenomas (6 of 6) were polyclonal and monoclonal, respectively, clonal analysis showed a nonrandom pattern of X chromosome inactivation consistent with a monoclonal lesion in 6 of 8 cases of telangiectatic FNH. The mean value of the ANGPT-1/ANGPT-2 mRNA ratio was 21.4 in FNH, 2.6 in adenomas, and 2.1 in telangiectatic FNH (P

Aims: Focal nodular hyperplasia-like lesions have rarely been described in cirrhotic livers. We describe five cases of such lesions., Methods and Results: Between 1998 and 2001, 146 liver transplants were performed at the Royal Free Hospital for cirrhosis of the liver. Nodular lesions identified in the livers removed at transplantation were defined histologically according to the International Working Party classification (Hepatology 1995; 22; 983). They were present in 63 of these livers, as follows: 36 dysplastic nodules, 121 macroregenerative nodules, and 71 hepatocellular carcinomas. In five patients, an additional 12 nodules (size range 4-23 mm, median 10.5 mm) showed histological features suggestive of focal nodular hyperplasia including mildly inflamed vascular fibrous septa, and ductular proliferation. Pre-transplantation imaging showed features suspicious for hepatocellular carcinoma, in three of these lesions (12, 23 and 23 mm diameter) from two different patients. These lesions were histologically indistinguishable from focal nodular hyperplasia occurring in non-cirrhotic livers, with fibrous scars and septa which contained vascular and ductular structures., Conclusions: It is important to recognize that these lesions may occur in the context of cirrhosis and that they should be considered in the differential diagnosis with hepatocellular carcinoma, dysplastic nodules and macroregenerative nodules.

In this study we analyzed by immunohistochemistry the expression of TGF-beta1 protein and TGF-beta receptors I and II in 4 low-grade dysplastic nodules, 2 high-grade dysplastic nodules, 6 early, 22 small, and 62 advanced hepatocellular carcinomas. The expression of TGF-beta1 protein by hepatocytes was decreased in advanced hepatocellular carcinoma compared with small or early hepatocellular carcinoma(P < .05). Frequent and intense staining of TGF-beta1 protein was noted in the sinusoidal endothelium of advanced hepatocellular carcinomas despite of its decreased staining in hepatocellular carcinoma cells. Reduced expression of TGF-beta receptors I and II compared with surrounding nontumorous tissue were noted from the early hepatocellular carcinoma stage suggesting that down-regulation of TGF-beta receptors is correlated with progression from premalignant to malignant phenotype. Reduced expression of both TGF-beta1 and TGF-beta receptor II in neoplastic hepatocytes were also significantly correlated with increased tumor size and increased proliferative activity(P < .05). These findings suggest that during hepatocarcinogenesis, the inhibitory effects of TGF-beta1 protein on hepatocellular carcinoma cells is outweighed by its effects on stromal elements, which, overall, contributes indirectly to a tumor growth stimulatory environment. Also, the growth-inhibitory effects of TGF-beta1 may have been further negated by reduced TGF-beta receptors on hepatocellular carcinoma cells.

Focal nodular hyperplasia (FNH) is a benign hepatocellular lesion composed of hyperplastic appearing hepatocytes arranged in nodules separated by fibrous septa that usually form a central stellate scar. Rare lesions that show unusual cytological or architectural features were reported as variants of focal nodular hyperplasia. We present the morphological features of a case of FNH with severe cytological atypia (so-called large cell change) in a 73-year-old man. In addition to diffuse cytological atypia, Mallory hyaline bodies were found in almost all lesional cells. This rare variant of FNH should be differentiated from other neoplastic lesions, in particular from the fibrolamellar variant of hepatocellular carcinoma.