Current histological classification of NAFLD: strength and limitations

Area of Science:

• Hepatology
• Pathology

Background:

• Nonalcoholic fatty liver disease (NAFLD) encompasses a range of liver conditions, from simple steatosis (NAFL) to inflammation and injury (NASH).
• Accurate histopathological evaluation of liver biopsies is crucial for NAFLD diagnosis due to the lack of precise non-invasive tests.

Purpose of the Study:

• To introduce and validate the SAF score for comprehensive histopathological assessment of NAFLD.
• To provide a standardized method for grading steatosis, activity, and fibrosis in NAFLD.

Main Methods:

• The proposed SAF score evaluates steatosis (S0-S3), activity (A0-A4, combining ballooning and lobular inflammation), and fibrosis (F0-F4).
• This semiquantitative score aims to standardize histological descriptions and assess changes in paired liver biopsies.

Main Results:

• Existing semiquantitative scoring systems for NAFLD have limitations and are not always useful in clinical practice.
• The SAF score offers a comprehensive approach to describing histopathological lesions in NAFLD, including borderline cases.

Conclusions:

• The SAF score provides a standardized and comprehensive method for assessing NAFLD and NASH histology.
• This score can aid in evaluating disease progression and treatment efficacy in clinical studies and practice.