Severe acute liver disease in adults: Contemporary role of histopathology.

Liver biopsies have consistently contributed to our understanding of the pathogenesis and aetiologies of acute liver disease. As other diagnostic modalities have been developed and refined, the role of biopsy in the management of patients with acute liver failure (ALF), acute-on-chronic liver failure (ACLF) and acute hepatitis, including acute liver injury (ALI), has changed. Liver biopsy remains particularly valuable when first-line diagnostic algorithms fail to determine aetiology. Despite not being identified as a mandatory diagnostic tool in recent clinical guidelines for the management of ALF or ACLF, many centres continue to undertake biopsies given the relative safety of transjugular biopsy in this setting. Several studies have demonstrated that liver biopsy can provide prognostic information, particularly in the context of so-called indeterminate hepatitis, and is extremely useful in excluding conditions such as metastatic tumours that would preclude transplantation. In addition, its widespread use of percutaneous biopsies in cases of less severe acute liver injury, for example in the establishment of a diagnosis of acute presentation of autoimmune hepatitis or confirmation of a probable or definite drug-induced liver injury (DILI), has meant that many centres have seen a shift in the ratio of specimens they are receiving from patients with chronic to acute liver disease. Histopathologists therefore need to be equipped to deal with these challenging specimens. This overview provides an insight into the contemporary role of biopsies (as well as explant and autopsy material) in diagnosing acute liver disease. It outlines up-to-date clinical definitions of liver injury and considers recent recommendations for the diagnosis of AIH and drug-induced, autoimmune-like hepatitis (DI-AIH).

IL-6-mediated endothelial injury impairs antiviral humoral immunity after bone marrow transplantation.

Endothelial function and integrity are compromised after allogeneic bone marrow transplantation (BMT), but how this affects immune responses broadly remains unknown. Using a preclinical model of CMV reactivation after BMT, we found compromised antiviral humoral responses induced by IL-6 signaling. IL-6 signaling in T cells maintained Th1 cells, resulting in sustained IFN-γ secretion, which promoted endothelial cell (EC) injury, loss of the neonatal Fc receptor (FcRn) responsible for IgG recycling, and rapid IgG loss. T cell-specific deletion of IL-6R led to persistence of recipient-derived, CMV-specific IgG and inhibited CMV reactivation. Deletion of IFN-γ in donor T cells also eliminated EC injury and FcRn loss. In a phase III clinical trial, blockade of IL-6R with tocilizumab promoted CMV-specific IgG persistence and significantly attenuated early HCMV reactivation. In sum, IL-6 invoked IFN-γ-dependent EC injury and consequent IgG loss, leading to CMV reactivation. Hence, cytokine inhibition represents a logical strategy to prevent endothelial injury, thereby preserving humoral immunity after immunotherapy.

Intestinal microbiota controls graft-versus-host disease independent of donor-host genetic disparity.

Acute graft-versus-host disease (aGVHD) remains a major limitation of allogeneic stem cell transplantation (SCT), and severe intestinal manifestation is the major cause of early mortality. Intestinal microbiota control MHC class II (MHC-II) expression by ileal intestinal epithelial cells (IECs) that promote GVHD. Here, we demonstrated that genetically identical mice of differing vendor origins had markedly different intestinal microbiota and ileal MHC-II expression, resulting in discordant GVHD severity. We utilized cohousing and antibiotic treatment to characterize the bacterial taxa positively and negatively associated with MHC-II expression. A large proportion of bacterial MHC-II inducers were vancomycin sensitive, and peri-transplant oral vancomycin administration attenuated CD4+ T cell-mediated GVHD. We identified a similar relationship between pre-transplant microbes, HLA class II expression, and both GVHD and mortality in a large clinical SCT cohort. These data highlight therapeutically tractable mechanisms by which pre-transplant microbial taxa contribute to GVHD independently of genetic disparity.

Relapsed nodular lymphocyte-predominant Hodgkin lymphoma presenting as severe paraneoplastic hepatitis: a case report.

BACKGROUND: Hematological malignancies are an infrequent but important cause of liver dysfunction. There are several mechanisms by which this can occur, including direct malignant infiltration of the hepatic parenchyma and/or vasculature, vanishing bile duct syndrome, and paraneoplastic hepatitis. Paraneoplastic hepatitis is an extremely rare mechanism by which a hematological malignancy can cause liver dysfunction, and we present the first case, to our knowledge, of paraneoplastic hepatitis caused by nodular lymphocyte-predominant Hodgkin lymphoma in the literature. CASE PRESENTATION: A 28-year-old Caucasian male presented with 3 weeks of fatigue, epigastric pain, and jaundice. His medical history was significant for early stage nodular lymphocyte-predominant Hodgkin lymphoma in the cervical region in remission for 5 years after primary treatment with involved-field radiotherapy. Liver biochemistry was normal at the time of treatment for lymphoma and there was no known liver disease before the current presentation. On physical examination, there was scleral icterus and ecchymoses, but no evidence of hepatic encephalopathy, other stigmata of chronic liver disease, or lymphadenopathy. A computed tomography scan of his neck, chest, abdomen, and pelvis showed heterogeneous enhancement of the liver, multiple enlarged upper abdominal lymph nodes, and an enlarged spleen with multiple rounded lesions. Portal and hepatic veins were patent. Initial workup for viral, autoimmune-, toxin-, and medication-related hepatitis was negative. A transjugular liver biopsy was performed with histology showing a predominantly T-cell mediated hepatitis with very extensive multiacinar hepatic necrosis, but no evidence of lymphoma within the liver. Retroperitoneal lymph node biopsy revealed nodular lymphocyte-predominant Hodgkin lymphoma. The patient's symptoms, bilirubin, and transaminases improved significantly after treatment with oral prednisolone and a staged introduction of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy. CONCLUSIONS: Nodular lymphocyte-predominant Hodgkin lymphoma may cause paraneoplastic hepatitis. Physicians should be aware of the possibility of this life-threatening presentation and the importance of early liver biopsy and treatment before acute liver failure occurs. Interestingly, paraneoplastic hepatitis did not occur when nodular lymphocyte-predominant Hodgkin lymphoma was first diagnosed and confined to the cervical region, but was the presenting feature of the recurrence below the diaphragm.

Phase Ib open-label, multicenter study of pixatimod, an activator of TLR9, in combination with nivolumab in subjects with microsatellite-stable metastatic colorectal cancer, metastatic pancreatic ductal adenocarcinoma and other solid tumors.

BACKGROUND: Pixatimod is a unique activator of the Toll-like Receptor 9 pathway. This phase I trial evaluated safety, efficacy and pharmacodynamics of pixatimod and PD-1 inhibitor nivolumab in immunologically cold cancers. METHODS: 3+3 dose escalation with microsatellite stable metastatic colorectal cancer (MSS mCRC) and metastatic pancreatic ductal adenocarcinoma (mPDAC) expansion cohorts. Participants received pixatimod once weekly as a 1-hour intravenous infusion plus nivolumab every 2 weeks. Objectives included assessment of safety, antitumor activity, pharmacodynamics, and pharmacokinetic profile. RESULTS: Fifty-eight participants started treatment. The maximum tolerated dose of pixatimod was 25 mg in combination with 240 mg nivolumab, which was used in the expansion phases of the study. Twenty-one grade 3-5 treatment-related adverse events were reported in 12 participants (21%); one participant receiving 50 mg pixatimod/nivolumab had a treatment-related grade 5 AE. The grade 3/4 rate in the MSS mCRC cohort (n=33) was 12%. There were no responders in the mPDAC cohort (n=18). In the MSS mCRC cohort, 25 participants were evaluable (initial postbaseline assessment scans >6 weeks); of these, three participants had confirmed partial responses (PR) and eight had stable disease (SD) for at least 9 weeks. Clinical benefit (PR+SD) was associated with lower Pan-Immune-Inflammation Value and plasma IL-6 but increased IP-10 and IP-10/IL-8 ratio. In an MSS mCRC participant with PR as best response, increased infiltration of T cells, dendritic cells, and to a lesser extent NK cells, were evident 5 weeks post-treatment. CONCLUSIONS: Pixatimod is well tolerated at 25 mg in combination with nivolumab. The efficacy signal and pharmacodynamic changes in MSS mCRC warrants further investigation. TRIAL REGISTRATION NUMBER: NCT05061017.

Patient-Reported Bowel, Urinary, and Sexual Outcomes After Laparoscopic-Assisted Resection or Open Resection for Rectal Cancer: The Australasian Laparoscopic Cancer of the Rectum Randomized Clinical Trial (ALaCart).

OBJECTIVE: The aim of this study was to compare patient-reported urinary, bowel, and sexual functioning of ALaCaRT Trial participants randomized to open or laparoscopic surgery for rectal cancer. SUMMARY BACKGROUND DATA: The primary endpoint, noninferiority of laparoscopic surgical resection adequacy, was not established. METHODS: Participants completed QLQ-CR29 at baseline, 3, and 12 months post-surgery. Additionally, women completed Rosen's Female Sexual Functioning Index (FSFI). Men completed the International Index of Erectile Function (IIEF) and QLQ-PR25. We compared the proportions of participants in each group who experienced moderate/severe symptoms/dysfunction at each time-point and compared mean difference scores from baseline to 12 months between groups. All analyses were intention-to-treat. Sexual functioning analyses included only the participants who expressed sexual interest at baseline. RESULTS: Baseline PRO compliance of 475 randomized participants was 88%. At 12 months, a lower proportion of open surgery participants experienced moderate-severe fecal incontinence and sore skin, compared to Laparoscopic participants, and a lower proportion of men randomized to open surgery experienced moderate-severe urinary symptoms. There were no differences at 3 months for bowel or urinary symptoms. Sexual functioning among sexually interested participants was similar between groups at 3 and 12 months; however, a lower proportion of women reported moderate to severe sexual dissatisfaction at 3 months in the open as compared to the laparoscopic group, (Rebecca.mercieca@sydney.edu.au., 95% CI 0.03-0.39). DISCUSSION: Despite the slightly lower proportions of open surgery participants self-reporting moderate-severe symptoms for 3 of 16 urinary/bowel domains, and lack of differences in sexual domains, it remains difficult to recommend one surgical approach over another for rectal resection.

Reliability of histologic assessment for NAFLD and development of an expanded NAFLD activity score.

BACKGROUND AND AIMS: The NASH Clinical Research Network histologic scoring system, the gold-standard NASH histology assessment for clinical trials, has demonstrated intrarater and interrater variability. An expert panel in a previous systematic Research and Development/University of California Los Angeles (RAND/UCLA) study determined that existing histologic scoring systems do not fully capture NASH disease activity and fibrosis, and standardized definitions of histologic features are needed. We evaluated the reliability of existing and alternate histologic measures and their correlations with a disease activity visual analog scale to propose optimal components for an expanded NAFLD activity score (NAS). APPROACH AND RESULTS: Four liver pathologists who were involved in the prior RAND/UCLA study underwent standardized training and multiple discussions with the goal of improving agreement. They were blinded to clinical information and scored histologic measures twice, ≥2 weeks apart, for 40 liver biopsies representing the full spectrum of NAFLD. Index intraclass correlation coefficient (ICC) estimates demonstrated intrarater (0.80-0.85) and interrater (0.60-0.72) reliability. Hepatocyte ballooning items had similar interrater ICCs (0.68-0.79), including those extending scores from 0-2 to 0-4. Steatosis measures (interrater ICCs, 0.72-0.80) correlated poorly with disease activity. Correlations with disease activity were largest for hepatocyte ballooning and Mallory-Denk bodies (MDBs), with both used to develop the expanded NAS (intrarater ICC, 0.90; interrater ICC, 0.80). Fibrosis measures had ICCs of 0.70-0.87. CONCLUSIONS: After extensive preparation among a group of experienced pathologists, we demonstrated improved reliability of multiple existing histologic NAFLD indices and fibrosis staging systems. Hepatocyte ballooning and MDBs most strongly correlated with disease activity and were used for the expanded NAS. Further validation including evaluation of responsiveness is required.

Consensus recommendations for histological criteria of autoimmune hepatitis from the International AIH Pathology Group: Results of a workshop on AIH histology hosted by the European Reference Network on Hepatological Diseases and the European Society of Pathology: Results of a workshop on AIH histology hosted by the European Reference Network on Hepatological Diseases and the European Society of Pathology.

BACKGROUND & AIMS: Diagnostic histological criteria for autoimmune hepatitis (AIH) have not been clearly established. Previously published criteria focused mainly on chronic AIH, in which inflammatory changes mainly occur in portal/periportal regions and may not be applicable to acute presentation of AIH, in which inflammatory changes are typically predominantly lobular in location. International consensus criteria for the diagnosis and assessment of disease severity in both acute and chronic AIH are thus urgently needed. METHODS: Seventeen expert liver pathologists convened at an international workshop and subsequently used a modified Delphi panel approach to establish consensus criteria for the histopathological diagnosis of AIH. RESULTS: The consensus view is that liver biopsy should remain standard for diagnosing AIH. AIH is considered likely, if there is a predominantly portal lymphoplasmacytic hepatitis with more than mild interface activity and/or more than mild lobular hepatitis in the absence of histological features suggestive of another liver disease. AIH is also considered likely if there is predominantly lobular hepatitis with or without centrilobular necroinflammation and at least one of the following features: portal lymphoplasmacytic hepatitis, interface hepatitis or portal-based fibrosis, in the absence of histological features suggestive of another liver disease. Emperipolesis and hepatocellular rosettes are not regarded as being specific for AIH. CONCLUSIONS: The criteria proposed in this consensus statement provide a uniform approach to the histological diagnosis of AIH, which is relevant for patients with an acute as well as a chronic presentation and to more accurately reflect the current understanding of liver pathology in AIH.

Therapeutic potential of macrophage colony-stimulating factor in chronic liver disease.

Resident and recruited macrophages control the development and proliferation of the liver. We have previously shown in multiple species that treatment with a macrophage colony stimulating factor (CSF1)-Fc fusion protein initiated hepatocyte proliferation and promoted repair in models of acute hepatic injury in mice. Here, we investigated the impact of CSF1-Fc on resolution of advanced fibrosis and liver regeneration, using a non-resolving toxin-induced model of chronic liver injury and fibrosis in C57BL/6J mice. Co-administration of CSF1-Fc with exposure to thioacetamide (TAA) exacerbated inflammation consistent with monocyte contributions to initiation of pathology. After removal of TAA, either acute or chronic CSF1-Fc treatment promoted liver growth, prevented progression and promoted resolution of fibrosis. Acute CSF1-Fc treatment was also anti-fibrotic and pro-regenerative in a model of partial hepatectomy in mice with established fibrosis. The beneficial impacts of CSF1-Fc treatment were associated with monocyte-macrophage recruitment and increased expression of remodelling enzymes and growth factors. These studies indicate that CSF1-dependent macrophages contribute to both initiation and resolution of fibrotic injury and that CSF1-Fc has therapeutic potential in human liver disease.

Complexity of ballooned hepatocyte feature recognition: Defining a training atlas for artificial intelligence-based imaging in NAFLD.

BACKGROUND & AIMS: Histologically assessed hepatocyte ballooning is a key feature discriminating non-alcoholic steatohepatitis (NASH) from steatosis (NAFL). Reliable identification underpins patient inclusion in clinical trials and serves as a key regulatory-approved surrogate endpoint for drug efficacy. High inter/intra-observer variation in ballooning measured using the NASH CRN semi-quantitative score has been reported yet no actionable solutions have been proposed. METHODS: A focused evaluation of hepatocyte ballooning recognition was conducted. Digitized slides were evaluated by 9 internationally recognized expert liver pathologists on 2 separate occasions: each pathologist independently marked every ballooned hepatocyte and later provided an overall non-NASH NAFL/NASH assessment. Interobserver variation was assessed and a 'concordance atlas' of ballooned hepatocytes generated to train second harmonic generation/two-photon excitation fluorescence imaging-based artificial intelligence (AI). RESULTS: The Fleiss kappa statistic for overall interobserver agreement for presence/absence of ballooning was 0.197 (95% CI 0.094-0.300), rising to 0.362 (0.258-0.465) with a ≥5-cell threshold. However, the intraclass correlation coefficient for consistency was higher (0.718 [0.511-0.900]), indicating 'moderate' agreement on ballooning burden. 133 ballooned cells were identified using a ≥5/9 majority to train AI ballooning detection (AI-pathologist pairwise concordance 19-42%, comparable to inter-pathologist pairwise concordance of between 8-75%). AI quantified change in ballooned cell burden in response to therapy in a separate slide set. CONCLUSIONS: The substantial divergence in hepatocyte ballooning identified amongst expert hepatopathologists suggests that ballooning is a spectrum, too subjective for its presence or complete absence to be unequivocally determined as a trial endpoint. A concordance atlas may be used to train AI assistive technologies to reproducibly quantify ballooned hepatocytes that standardize assessment of therapeutic efficacy. This atlas serves as a reference standard for ongoing work to refine how ballooning is classified by both pathologists and AI. LAY SUMMARY: For the first time, we show that, even amongst expert hepatopathologists, there is poor agreement regarding the number of ballooned hepatocytes seen on the same digitized histology images. This has important implications as the presence of ballooning is needed to establish the diagnosis of non-alcoholic steatohepatitis (NASH), and its unequivocal absence is one of the key requirements to show 'NASH resolution' to support drug efficacy in clinical trials. Artificial intelligence-based approaches may provide a more reliable way to assess the range of injury recorded as "hepatocyte ballooning".

ROCK2 inhibition attenuates profibrogenic immune cell function to reverse thioacetamide-induced liver fibrosis.

BACKGROUND & AIMS: Fibrosis, the primary cause of morbidity in chronic liver disease, is induced by pro-inflammatory cytokines, immune cell infiltrates, and tissue resident cells that drive excessive myofibroblast activation, collagen production, and tissue scarring. Rho-associated kinase 2 (ROCK2) regulates key pro-fibrotic pathways involved in both inflammatory reactions and altered extracellular matrix remodelling, implicating this pathway as a potential therapeutic target. METHODS: We used the thioacetamide-induced liver fibrosis model to examine the efficacy of administration of the selective ROCK2 inhibitor KD025 to prevent or treat liver fibrosis and its impact on immune composition and function. RESULTS: Prophylactic and therapeutic administration of KD025 effectively attenuated thioacetamide-induced liver fibrosis and promoted fibrotic regression. KD025 treatment inhibited liver macrophage tumour necrosis factor production and disrupted the macrophage niche within fibrotic septae. ROCK2 targeting in vitro directly regulated macrophage function through disruption of signal transducer and activator of transcription 3 (STAT3)/cofilin signalling pathways leading to the inhibition of pro-inflammatory cytokine production and macrophage migration. In vivo, KDO25 administration significantly reduced STAT3 phosphorylation and cofilin levels in the liver. Additionally, livers exhibited robust downregulation of immune cell infiltrates and diminished levels of retinoic acid receptor-related orphan receptor gamma (RORγt) and B-cell lymphoma 6 (Bcl6) transcription factors that correlated with a significant reduction in liver IL-17, splenic germinal centre numbers and serum IgG. CONCLUSIONS: As IL-17 and IgG-Fc binding promote pathogenic macrophage differentiation, together our data demonstrate that ROCK2 inhibition prevents and reverses liver fibrosis through direct and indirect effects on macrophage function and highlight the therapeutic potential of ROCK2 inhibition in liver fibrosis. LAY SUMMARY: By using a clinic-ready small-molecule inhibitor, we demonstrate that selective ROCK2 inhibition prevents and reverses hepatic fibrosis through its pleiotropic effects on pro-inflammatory immune cell function. We show that ROCK2 mediates increased IL-17 production, antibody production, and macrophage dysregulation, which together drive fibrogenesis in a model of chemical-induced liver fibrosis. Therefore, in this study, we not only highlight the therapeutic potential of ROCK2 targeting in chronic liver disease but also provide previously undocumented insights into our understanding of cellular and molecular pathways driving the liver fibrosis pathology.

Bone Marrow Regulatory T Cells Are a Unique Population, Supported by Niche-Specific Cytokines and Plasmacytoid Dendritic Cells, and Required for Chronic Graft-Versus-Host Disease Control.

Regulatory T cell (Treg) reconstitution is essential for reestablishing tolerance and maintaining homeostasis following stem-cell transplantation. We previously reported that bone marrow (BM) is highly enriched in autophagy-dependent Treg and autophagy disruption leads to a significant Treg loss, particularly BM-Treg. To correct the known Treg deficiency observed in chronic graft-versus-host disease (cGVHD) patients, low dose IL-2 infusion has been administered, substantially increasing peripheral Treg (pTreg) numbers. However, as clinical responses were only seen in ∼50% of patients, we postulated that pTreg augmentation was more robust than for BM-Treg. We show that BM-Treg and pTreg have distinct characteristics, indicated by differential transcriptome expression for chemokine receptors, transcription factors, cell cycle control of replication and genes linked to Treg function. Further, BM-Treg were more quiescent, expressed lower FoxP3, were highly enriched for co-inhibitory markers and more profoundly depleted than splenic Treg in cGVHD mice. In vivo our data are consistent with the BM and not splenic microenvironment is, at least in part, driving this BM-Treg signature, as adoptively transferred splenic Treg that entered the BM niche acquired a BM-Treg phenotype. Analyses identified upregulated expression of IL-9R, IL-33R, and IL-7R in BM-Treg. Administration of the T cell produced cytokine IL-2 was required by splenic Treg expansion but had no impact on BM-Treg, whereas the converse was true for IL-9 administration. Plasmacytoid dendritic cells (pDCs) within the BM also may contribute to BM-Treg maintenance. Using pDC-specific BDCA2-DTR mice in which diptheria toxin administration results in global pDC depletion, we demonstrate that pDC depletion hampers BM, but not splenic, Treg homeostasis. Together, these data provide evidence that BM-Treg and splenic Treg are phenotypically and functionally distinct and influenced by niche-specific mediators that selectively support their respective Treg populations. The unique properties of BM-Treg should be considered for new therapies to reconstitute Treg and reestablish tolerance following SCT.

IFN-λ therapy prevents severe gastrointestinal graft-versus-host disease.

Immunopathology and intestinal stem cell (ISC) loss in the gastrointestinal (GI) tract is the prima facie manifestation of graft-versus-host disease (GVHD) and is responsible for significant mortality after allogeneic bone marrow transplantation (BMT). Approaches to prevent GVHD to date focus on immune suppression. Here, we identify interferon-λ (IFN-λ; interleukin-28 [IL-28]/IL-29) as a key protector of GI GVHD immunopathology, notably within the ISC compartment. Ifnlr1-/- mice displayed exaggerated GI GVHD and mortality independent of Paneth cells and alterations to the microbiome. Ifnlr1-/- intestinal organoid growth was significantly impaired, and targeted Ifnlr1 deficiency exhibited effects intrinsic to recipient Lgr5+ ISCs and natural killer cells. PEGylated recombinant IL-29 (PEG-rIL-29) treatment of naive mice enhanced Lgr5+ ISC numbers and organoid growth independent of both IL-22 and type I IFN and modulated proliferative and apoptosis gene sets in Lgr5+ ISCs. PEG-rIL-29 treatment improved survival, reduced GVHD severity, and enhanced epithelial proliferation and ISC-derived organoid growth after BMT. The preservation of ISC numbers in response to PEG-rIL-29 after BMT occurred both in the presence and absence of IFN-λ-signaling in recipient natural killer cells. IFN-λ is therefore an attractive and rapidly testable approach to prevent ISC loss and immunopathology during GVHD.

Fifty years of impact on liver pathology: a history of the Gnomes.

Professional societies play a major role in medicine and science. The societies tend to be large with well-developed administrative structures. An additional model, however, is based on small groups of experts who meet regularly in an egalitarian model in order to discuss disease-specific scientific and medical problems. In order to illustrate the effectiveness of this model, the history and practices are examined of a long-standing successful example, the International Liver Pathology Group, better known as the Gnomes. The history shows that groups such as the Gnomes offer a number of important benefits not available in larger societies and nurturing such groups advances science and medicine in meaningful ways. The success of the Gnomes' approach provides a road map for future small scientific groups.

Evaluation of the histological variability of core and wedge biopsies in nonalcoholic fatty liver disease in bariatric surgical patients.

BACKGROUND: Liver biopsy remains the gold standard for characterizing and evaluating treatment response in nonalcoholic fatty liver disease (NAFLD). Liver heterogeneity and sampling variability can affect the reliability of results. This study aimed to compare histological variability of intraoperative wedge and core liver biopsies from different lobes in bariatric patients, to better inform surgeons on biopsy method and guide interpretation of results. METHODS: We prospectively recruited bariatric surgical patients. Intraoperative core biopsies were taken from the left and right lobe, with a wedge biopsy taken from the left. All biopsies were graded by a specialist liver pathologist, blinded to clinical details and biopsy site. Concordance of histological findings between sites was evaluated. RESULTS: There were 91 participants (72.2% female), mean age 46.8 ± 12.0 years, body mass index 45.9 ± 9.4 kg/m2. There was no significant pattern for up- or down-grading disease dependent on biopsy technique. Moderate to strong agreement was seen in the presence of NAFLD and nonalcoholic steatohepatitis (NASH, κ = 0.609-0.865, p < 0.001) between biopsy sites. Individual components (steatosis, inflammation, ballooning) showed weaker agreement (κ = 0.386-0.656, p < 0.01). Fibrosis showed particularly poor agreement (κ = 0.223-0.496, p < 0.01). Detection of pathology improved with a combination of biopsy techniques, compared to a single biopsy method. CONCLUSION: Overall diagnosis of NAFLD or NASH shows good agreement between biopsy sites, but individual components, particularly fibrosis stage, vary significantly. Clinicians should consider biopsies from varied sites, to better assess liver disease severity. These data have important implications in fibrosis assessment of NAFLD and are relevant in the interpretation of histological efficacy of investigational pharmacotherapies. TRIAL REGISTRATION: ACTRN12615000875505 (Australian Clinical Trials Register).

ASS1 Overexpression: A Hallmark of Sonic Hedgehog Hepatocellular Adenomas; Recommendations for Clinical Practice.

Until recently, 10% of hepatocellular adenomas (HCAs) remained unclassified (UHCA). Among the UHCAs, the sonic hedgehog HCA (shHCA) was defined by focal deletions that fuse the promoter of Inhibin beta E chain with GLI1. Prostaglandin D2 synthase was proposed as immunomarker. In parallel, our previous work using proteomic analysis showed that most UHCAs constitute a homogeneous subtype associated with overexpression of argininosuccinate synthase (ASS1). To clarify the use of ASS1 in the HCA classification and avoid misinterpretations of the immunohistochemical staining, the aims of this work were to study (1) the link between shHCA and ASS1 overexpression and (2) the clinical relevance of ASS1 overexpression for diagnosis. Molecular, proteomic, and immunohistochemical analyses were performed in UHCA cases of the Bordeaux series. The clinico-pathological features, including ASS1 immunohistochemical labeling, were analyzed on a large international series of 67 cases. ASS1 overexpression and the shHCA subgroup were superimposed in 15 cases studied by molecular analysis, establishing ASS1 overexpression as a hallmark of shHCA. Moreover, the ASS1 immunomarker was better than prostaglandin D2 synthase and only found positive in 7 of 22 shHCAs. Of the 67 UHCA cases, 58 (85.3%) overexpressed ASS1, four cases were ASS1 negative, and in five cases ASS1 was noncontributory. Proteomic analysis performed in the case of doubtful interpretation of ASS1 overexpression, especially on biopsies, can be a support to interpret such cases. ASS1 overexpression is a specific hallmark of shHCA known to be at high risk of bleeding. Therefore, ASS1 is an additional tool for HCA classification and clinical diagnosis.

Large size and haemorrhage are not contraindications to laparoscopic resection of hepatocellular adenoma.

BACKGROUND: Hepatocellular adenoma (HCA) is a hepatocyte derived neoplastic lesion with an increasing incidence and a strong association with oestrogen therapy. Laparoscopic resection has proven safe for small, non-ruptured lesions whilst its use for large adenomas (≥10 cm) and cases of haemorrhage requires further investigation. METHODS: All patients undergoing liver resection for HCA at the Royal Brisbane Hospital between January 2003 and April 2018 were analysed. Ethics approval was obtained. RESULTS: Thirty-three laparoscopic and three open resections were performed in 35 patients, all female, with a median age of 35 years (range 14-75). Nine laparoscopic resections were performed for large adenomas (≥10 cm) and 17 laparoscopic resections were performed for adenomas of intermediate size (5-9.9 cm). Only one conversion to open surgery was required for an intermediate sized tumour. Haemorrhage, either intratumoural, intraparenchymal or free intraperitoneal was the indication for resection in six of the 33 laparoscopic cases. Median operative time was 143 and 266 min for laparoscopically resected intermediate and large lesions, respectively. The median length of stay was 5 days (range 4-9) and no major complications were observed in the laparoscopic group. ß-catenin mutation was seen in four of nine large adenomas whereas the inflammatory subtype constituted 11 of 17 intermediate sized lesions. CONCLUSION: Laparoscopic surgery has been demonstrated to be safe for the resection of HCA in this group of patients. Importantly, haemorrhage and/or large size were not barriers to laparoscopic resection.