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World J Gastroenterol. Nov 14, 2014; 20(42): 15539-15548
Published online Nov 14, 2014. doi: 10.3748/wjg.v20.i42.15539
Histopathology of nonalcoholic fatty liver disease/nonalcoholic steatohepatitis
Yoshihisa Takahashi, Toshio Fukusato
Yoshihisa Takahashi, Toshio Fukusato, Department of Pathology, Teikyo University School of Medicine, Tokyo 173-8605, Japan
Author contributions: Takahashi Y wrote the manuscript; Fukusato T checked and revised the manuscript.
Correspondence to: Yoshihisa Takahashi, MD, Associate Professor, Department of Pathology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan. ytakaha-tky@umin.ac.jp
Telephone: +81-3-39641211 Fax: +81-3-39649622
Received: January 3, 2014
Revised: March 5, 2014
Accepted: April 30, 2014
Published online: November 14, 2014
Abstract

Nonalcoholic fatty liver disease (NAFLD), a hepatic manifestation of metabolic syndrome, is the most common chronic liver disease, and the prevalence is rapidly increasing worldwide. Nonalcoholic steatohepatitis (NASH), the severe form of NAFLD, can progress to liver cirrhosis and hepatocellular carcinoma (HCC). Although noninvasive clinical scores and image-based diagnosis for NAFLD have improved, histopathological evaluation of biopsy specimens remains the gold standard for diagnosing NAFLD/NASH. Steatosis, lobular inflammation, and hepatocellular ballooning are all necessary components for the diagnosis of NASH; fibrosis is also typically observed. Other histopathological abnormalities commonly observed in NASH include hepatocellular glycogenated nuclei, lipogranulomas, and acidophil bodies. The characteristics of pediatric NAFLD/NASH differ from adult NAFLD/NASH. Specifically, steatosis and portal inflammation are more severe in pediatric NAFLD, while intralobular inflammation and perisinusoidal fibrosis are milder. Although interobserver agreement for evaluating the extent of steatosis and fibrosis is high, agreement is low for intralobular and portal inflammation. A recently reported histological variant of HCC, steatohepatitic HCC (SH-HCC), shows features that resemble non-neoplastic steatohepatitis, and is thought to be strongly associated with underlying NASH. In this report, we review the histopathological features of NAFLD/NASH.

Keywords: Histopathology, Nonalcoholic fatty liver disease, Nonalcoholic steatohepatitis, Pediatric, Interobserver variation

Core tip: Nonalcoholic fatty liver disease (NAFLD), a hepatic manifestation of metabolic syndrome, is the most common chronic liver disease, with a rapidly increasing prevalence worldwide. Nonalcoholic steatohepatitis (NASH), the severe form of NAFLD, can progress to liver cirrhosis and hepatocellular carcinoma. Although noninvasive clinical scores and image-based diagnosis for NAFLD have improved, histopathological evaluation of biopsy specimens remains the gold standard for diagnosing NAFLD/NASH. In this report, we review the histopathological features of NAFLD/NASH.