Non-alcoholic fatty liver disease other diagnostic studies

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Aditya Ganti M.B.B.S. [2] Parth Vikram Singh, MBBS[3]

Liver biopsy may be helpful in the diagnosis of non-alcoholic fatty liver disease. Findings on biopsy include macrovesicular steatosis, inflammation, ballooning degeneration, zone 3 perivenular/periportal/perisinusoidal fibrosis and, finally, mallory bodies.

• Liver biopsy is considered as a gold-standard for diagnosing, grading, and staging NAFLD, but it is invasive, costly, and associated with rare acute bleeding. Liver biopsy is not typically required to diagnose MASLD, but may be useful when the etiology of liver disease is uncertain, when noninvasive tests are inconclusive, or when MASLD coexists with other liver diseases such as autoimmune hepatitis or viral hepatitis.
• Invasive test
• Associated with significant bleeding risk in patients with clotting abnormalities due to hepatic disease.

Complications of liver biopsy are rare but include

• Pain
• Hypotension
• Peritonitis
• Intraperitoneal hemorrhage
• Biliary injury

Classically, biopsy reveals:^[1][2]

• Macrovesicular steatosis
• Inflammatory cells
• Ballooning degeneration
• Zone 3 perivenular/periportal/perisinusoidal fibrosis
• Mallory bodies

• Histologic changes in NAFLD are very similar to those in alcoholic hepatitis and may also mimic those seen in chronic HCV infection.
• The spectrum of abnormalities varies from simple bland steatosis to NASH, in which steatosis is associated with mixed inflammatory cell infiltration, mostly lobular, and liver injury.
• Cell injury is manifested by hepatocyte ballooning as well as by Mallory hyaline and acidophilic bodies.
• Fibrosis is classically perisinusoidal/perivenular and may lead to bridging fibrosis and cirrhosis.
• Although portal tracts are relatively spared in adult NAFLD, children with this condition may have a predominance of portal inflammation and fibrosis as opposed to lobular involvement.
• Compared with alcoholic hepatitis, NASH is associated with a higher prevalence of nuclear vacuoles and steatosis, while alcoholic hepatitis tends to produce periportal and pericellular fibrosis.
• Alcoholic hepatitis presents with identical histology but patient history and/or biochemistry will indicate prolonged, excessive alcohol intake.^[3]

Depending on degree of steatosis, necroinflammatory activity, and degree of fibrosis non-alcoholic liver disease can be classified as follows:

NAFLD activity score is employed for grading steatohepatitis of NASH. NAS represents the sum of scores for steatosis, lobular inflammation, and ballooning.^[4]

Based on the degree of fibrosis on biospy NASH can be classified into 5 stages.^[5]

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