Nonalcoholic steatohepatitis: definition and pathology

Area of Science:

• Hepatology
• Gastroenterology
• Pathology

Background:

• Nonalcoholic steatohepatitis (NASH) is a progressive chronic liver disease affecting adults and children.
• Its natural history varies, potentially leading to end-stage liver disease, cirrhosis, and recurrence in liver transplants.
• Identifying progression markers is crucial for managing this condition.

Purpose of the Study:

• To review the diagnostic challenges and histological features of nonalcoholic steatohepatitis (NASH).
• To discuss the established and debated histological criteria for NASH diagnosis.
• To highlight the importance of a standardized grading and staging system for NASH.

Main Methods:

• Review of current literature on nonalcoholic steatohepatitis (NASH) diagnosis and histopathology.
• Analysis of accepted histological features, including steatosis, ballooning degeneration, inflammation, and fibrosis.
• Discussion of diagnostic limitations of clinical and laboratory evaluations.

Main Results:

• Liver biopsy remains the gold standard for diagnosing nonalcoholic steatohepatitis (NASH), as clinical and laboratory findings are unreliable.
• Key histological features include steatosis, hepatocyte ballooning, inflammation, and perivenular/perisinusoidal fibrosis.
• Differences in presentation exist between pediatric and adult NASH, with portal inflammation more prominent in children.

Conclusions:

• Accurate diagnosis of nonalcoholic steatohepatitis (NASH) requires expert liver biopsy interpretation.
• Standardized histological criteria and grading systems are essential for consistent diagnosis and reporting of NASH.
• Further research is needed to refine diagnostic criteria and understand NASH progression.