A 52-year-old male with a 20-year history of heavy alcohol consumption (60–80 g/day) presents with jaundice, ascites, and hepatic encephalopathy. Imaging and biopsy confirm cirrhosis. The histopathology shows uniform small regenerative nodules <3 mm separated by thin fibrous septa, with evidence of Mallory-Denk bodies and pericellular fibrosis in a perivenular distribution. The gross appearance of the liver is finely granular ("hobnail liver"). This pattern corresponds to the cirrhosis type marked **B** in the diagram. Which of the following pathophysiologic mechanisms is MOST directly responsible for the pericentral/perivenular fibrosis pattern seen in this patient's alcoholic cirrhosis?
A. Viral replication in hepatocytes causing diffuse inflammation and random nodule formation throughout the liver
B. Immune-mediated destruction of bile ducts with progressive cholestasis and secondary biliary fibrosis
C. Cardiac venous congestion causing centrolobular necrosis and fibrosis around the hepatic venules
D. Acetaldehyde-mediated hepatocyte injury and hepatic stellate cell activation in Zone 3 (perivenular region), driven by alcohol dehydrogenase and CYP2E1 metabolism
Explanation
Why Acetaldehyde-mediated hepatocyte injury and hepatic stellate cell activation in Zone 3 is right
Alcoholic cirrhosis (Laennec cirrhosis, marked B) is characterized by micronodular architecture with pericentral/perivenular (Zone 3) fibrosis. Chronic alcohol metabolism via alcohol dehydrogenase and the inducible CYP2E1 system generates acetaldehyde, which is directly hepatotoxic and causes protein adducts and mitochondrial dysfunction. This injury, combined with oxidative stress from CYP2E1 and increased NADH/NAD+ ratio, activates hepatic stellate cells preferentially in the perivenular Zone 3 region, leading to collagen deposition and the characteristic thin, uniform fibrous septa of Laennec cirrhosis. This is the pathognomonic pattern of alcoholic liver disease (Robbins & Cotran, 10th ed; AASLD ALD Guidelines).
Why each distractor is wrong
Immune-mediated destruction of bile ducts: This describes primary biliary cirrhosis (PBC) or biliary cirrhosis (marked C), not alcoholic cirrhosis. Alcoholic cirrhosis is not characterized by bile duct destruction.
Cardiac venous congestion: This describes cardiac cirrhosis (marked D), which causes centrolobular necrosis and fibrosis around hepatic venules due to chronic passive congestion. Alcoholic cirrhosis has a different pathogenesis unrelated to cardiac hemodynamics.
Viral replication causing diffuse inflammation: This describes viral hepatitis-related cirrhosis (marked A — macronodular cirrhosis post-viral), which typically produces larger regenerative nodules and random distribution of fibrosis, not the uniform micronodular pattern of alcoholic cirrhosis.
High-YieldNEET PG
Alcoholic cirrhosis = Laennec cirrhosis = micronodular + perivenular (Zone 3) fibrosis + Mallory-Denk bodies; pathogenesis centers on acetaldehyde toxicity and stellate cell activation; AST:ALT >2:1 is the biochemical hallmark.
