Abstract Nonalcoholic fatty liver disease (NAFLD) is the liver injury most often associated with disorders of insulin resistance, including obesity, diabetes and the metabolic syndrome. The term ...encompasses several patterns of liver injury, including a relatively benign condition of steatosis without hepatocellular injury, nonalcoholic steatohepatitis (NASH), and a pattern of zone 1 steatosis, inflammation and fibrosis mainly observed in prepubertal children. Staging and grading systems have been developed to characterize the histological changes in NAFLD, mainly as a tool for clinical research. The histological features of NAFLD across these different manifestations and the scoring systems used to evaluate disease severity are discussed.
Nonalcoholic fatty liver disease (NAFLD) is the liver disease associated with obesity, diabetes, and the metabolic syndrome. Although steatosis is a key histologic feature, liver biopsies of patients ...with NAFLD can show a wide range of findings. Nonalcoholic steatohepatitis (NASH) is a progressive subtype of NAFLD first defined by analogy to alcoholic hepatitis. Young children may have an alternate pattern of progressive NAFLD characterized by a zone 1 distribution of steatosis, inflammation, and fibrosis. Several grading and staging systems exist, but all require adequate biopsies. Although NASH generally shows fibrosis progression over time, some patients show regression of disease.
Nonalcoholic fatty liver disease (NAFLD) results in histologically complex specific and nonspecific injury patterns. In clinical research of NAFLD, the liver biopsy evaluation provides a wealth of ...information on the architectural arrangement and severity of a variety of histologic changes, including steatosis, inflammation, cellular injury, and fibrosis. This information is summarized as an overall diagnostic category, such steatosis or steatohepatitis and the severity of the injury can be graded and staged. Histopathologic disease classification in NAFLD is related to but separate from evaluation of individual histologic lesions. The patient population under study may affect the prevalence of histologic findings and in particular, pediatric patients with NAFLD may show a higher prevalence of zone 1 steatosis and periportal fibrosis as compared with adult populations. For the purposes of clinical research, it is important to provide the pathologist with biopsies that are adequate to classify the disease process as well as to grade and stage the changes. A current understanding of NAFLD pathologic classification, as well as nuances of grading and staging, is presented in this review.
The evaluation of liver biopsies in suspected drug-induced liver injury (DILI) can be complex. The biopsy may be approached systematically, by identification of histologic lesions and then ...identification of the overall pattern of injury. Potential DILI must be separated from concomitant non-DILI liver disease. The findings can be analyzed with respect to the various prescription and nonprescription medications and dietary supplements under suspicion to provide a complete interpretation of the findings. The pathologic findings, the histologic differential diagnosis, and expert interpretation are part of a complete biopsy assessment and provide information that is of greatest value in patient management.
There is increasing recognition of a prothrombotic state in COVID-19. Post-mortem examination can provide important mechanistic insights.
We present a COVID-19 autopsy series including findings in ...lungs, heart, kidneys, liver, and bone, from a New York academic medical center.
In seven patients (four female), regardless of anticoagulation status, all autopsies demonstrated platelet-rich thrombi in the pulmonary, hepatic, renal, and cardiac microvasculature. Megakaryocytes were seen in higher than usual numbers in the lungs and heart. Two cases had thrombi in the large pulmonary arteries, where casts conformed to the anatomic location. Thrombi in the IVC were not found, but the deep leg veins were not dissected. Two cases had cardiac venous thrombosis with one case exhibiting septal myocardial infarction associated with intramyocardial venous thrombosis, without atherosclerosis. One case had focal acute lymphocyte-predominant inflammation in the myocardium with no virions found in cardiomyocytes. Otherwise, cardiac histopathological changes were limited to minimal epicardial inflammation (n = 1), early ischemic injury (n = 3), and mural fibrin thrombi (n = 2). Platelet-rich peri‑tubular fibrin microthrombi were a prominent renal feature. Acute tubular necrosis, and red blood cell and granular casts were seen in multiple cases. Significant glomerular pathology was notably absent. Numerous platelet-fibrin microthrombi were identified in hepatic sinusoids. All lungs exhibited diffuse alveolar damage (DAD) with a spectrum of exudative and proliferative phases including hyaline membranes, and pneumocyte hyperplasia, with viral inclusions in epithelial cells and macrophages. Three cases had superimposed acute bronchopneumonia, focally necrotizing.
In this series of seven COVID-19 autopsies, thrombosis was a prominent feature in multiple organs, in some cases despite full anticoagulation and regardless of timing of the disease course, suggesting that thrombosis plays a role very early in the disease process. The finding of megakaryocytes and platelet-rich thrombi in the lungs, heart and kidneys suggests a role in thrombosis.
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Summary Background The bile acid derivative 6-ethylchenodeoxycholic acid (obeticholic acid) is a potent activator of the farnesoid X nuclear receptor that reduces liver fat and fibrosis in animal ...models of fatty liver disease. We assessed the efficacy of obeticholic acid in adult patients with non-alcoholic steatohepatitis. Methods We did a multicentre, double-blind, placebo-controlled, parallel group, randomised clinical trial at medical centres in the USA in patients with non-cirrhotic, non-alcoholic steatohepatitis to assess treatment with obeticholic acid given orally (25 mg daily) or placebo for 72 weeks. Patients were randomly assigned 1:1 using a computer-generated, centrally administered procedure, stratified by clinical centre and diabetes status. The primary outcome measure was improvement in centrally scored liver histology defined as a decrease in non-alcoholic fatty liver disease activity score by at least 2 points without worsening of fibrosis from baseline to the end of treatment. A planned interim analysis of change in alanine aminotransferase at 24 weeks undertaken before end-of-treatment (72 weeks) biopsies supported the decision to continue the trial (relative change in alanine aminotransferase −24%, 95% CI −45 to −3). A planned interim analysis of the primary outcome showed improved efficacy of obeticholic acid (p=0·0024) and supported a decision not to do end-of-treatment biopsies and end treatment early in 64 patients, but to continue the trial to obtain the 24-week post-treatment measures. Analyses were done by intention-to-treat. This trial was registered with ClinicalTrials.gov , number NCT01265498. Findings Between March 16, 2011, and Dec 3, 2012, 141 patients were randomly assigned to receive obeticholic acid and 142 to placebo. 50 (45%) of 110 patients in the obeticholic acid group who were meant to have biopsies at baseline and 72 weeks had improved liver histology compared with 23 (21%) of 109 such patients in the placebo group (relative risk 2·2, 95% CI 1·4 to 3·3; p=0·0002). 33 (23%) of 141 patients in the obeticholic acid developed pruritus compared with nine (6%) of 142 in the placebo group. Interpretation Obeticholic acid improved the histological features of non-alcoholic steatohepatitis, but its long-term benefits and safety need further clarification. Funding National Institute of Diabetes and Digestive and Kidney Diseases, Intercept Pharmaceuticals.
The use of liver biopsy to diagnose hepatocellular carcinoma is governed by the balance of the risks of the procedure (morbidity, mortality, inadequate sampling), the relative utility of non-invasive ...techniques and the benefits of precise diagnosis, prognostic and theragnostic information and access to tissue for molecular analysis. In this issue of Hepatology, identification of the macrotrabecular subtype of hepatocellular carcinoma on liver biopsy is shown to add clinically useful prognostic information as well as molecular correlations.
When a patient with suspected drug‐induced liver injury (DILI) undergoes liver biopsy, the pathologist is confronted with two major challenges. The first and most important is to establish the ...pattern(s) of injury which are present. Patterns of injury represent stereotypical responses of an organ to injury and relate to specific aetiologies of liver damage. The pattern of injury and the histological details of that injury can then be analysed with respect to the patient's intercurrent diseases and medication history. The specific expertise of the pathologist can be used to weigh the prospect of DILI against the likelihood of other explanations of injury. The second challenge is to characterize specific types of injury and the severity of injury, both of which may have importance for clinical decision‐making and prognosis. The pathologist's report should convey both an accurate description of the pathology as well its interpretation.
Drug‐induced liver injury (DILI) presents unique challenges to the pathologist. It is not only an uncommon reason for liver biopsy, but the pathology of DILI is spread across the entire spectrum of ...hepatic injury patterns. It is important for the pathologist to suspect DILI when the histological changes are unusual or out of synchronicity with the patient's history. A systematic evaluation approach will yield the most information. It begins with the characterization of the general pattern of injury which, for most cases, will be found in a handful of necroinflammatory and cholestatic patterns. A careful assessment of the severity of injury across the various anatomic compartments will provide information on the probable natural history of the injury. Correlation of liver injury with the patient's medication history and clinical findings will help to narrow the differential diagnosis, particularly when it is recognized that most drugs have a limited range of histological findings and vary in their propensity to cause injury. This review provides an overview of the assessment of the liver biopsy and its use to confirm or exclude particular drugs as contributing to the patient's liver injury.
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