Steatotic liver disease

Last revised by Arlene Campos on 12 Feb 2025

Steatotic liver disease is the abnormal accumulation of intracellular triglycerides and other lipids in hepatocytes. It can be widespread and associated with inflammation, with the potential to progress to liver fibrosiscirrhosis, and liver failure. It is also associated with hepatocellular carcinoma, cardiovascular disease, and death.

Some consider the terms "nonalcoholic" and "fatty" derogatory, and the term steatotic liver disease is preferred 12, although the former remain in common use. Additionally, the use of the term "fatty infiltration" is incorrect because the abnormal lipid accumulation is intracellular, not extracellular.

Steatotic liver disease includes several separate entities 12:

The global prevalence of MASLD is increasing and was estimated at 30% of the global population in 2023 4. It is now the most common chronic liver disease, and the prevalence is projected to increase to over 55% by 2040 11.

Liver biopsy is the gold standard for diagnosis; the histological definition requires a minimum of 5% macrovesicular steatosis 5. Liver tests may be normal or liver enzymes may be elevated if the liver is inflamed. Imaging can also be used to assess fat content, see below.

Clinical features include fatigue and right upper quadrant pain and hepatomegaly, however most individuals are asymptomatic.

Histology shows macrovesicular lipid accumulation within the affected hepatocytes, with or without inflammation 6.

On imaging, steatosis can broadly be divided into two groups:

Unusual patterns such as multifocal nodular hepatic steatosis can be mistaken for metastases 9.

Ultrasound B-mode imaging is preferred as the first-line diagnostic modality for hepatic steatosis because of its wide availability, low cost, non-invasive, does not expose to ionizing radiation, repeatable, and well accepted by patients 2.

The degree of diffuse hepatic steatosis can be graded according to several different scoring systems, including the Hamaguchi score, US-FLI score, and hepatorenal sonographic index 2.

Attenuation imaging is also another new method which can be used for quantifying degree of steatosis.

Liver attenuation of < 40-45 HU on non-contrast CT identifies moderate hepatic steatosis (> 20-33% at biopsy) with a sensitivity of 82% and specificity of 94% 7. Of course other factors affect attenuation, such as edema, protein content and iron or iodine deposition.

Proton density fat fraction is accurate and correlates well with biopsy 8.

Cases and figures

  • Case 1: focal
  • Case 2: diffuse
  • Case 4: diffuse, GB equalization
  • Case 3: diffuse, with metastases
  • Case 5: focal, mass-like steatohepatitis
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