Quantitation and serial section observations of focal venocclusive lesions of hepatic veins in liver cirrhosis.

The pathogenesis and functional significance of the venocclusive (VO) lesions in small hepatic veins occurring in liver cirrhosis, remain controversial. The present study, using quantitative examination and serial sections has disclosed that these lesions are present in 71.7% of 106 autopsy livers with alcoholic, HBsAg-positive, biliary or cryptogenic cirrhosis. The lesions were usually focal: their number in a liver section (10 cm2) was below 15 in 86.7% of the livers having them. The incidence and morphology of the lesions appeared similar in cirrhotic livers with different aetiology. Serial sections disclosed that the affected veins disappeared within the fibrous stroma at one side and were directly connected with the patent larger hepatic veins at other side, indicating that these veins had lost their function as a draining vein of the hepatic parenchyma. In addition, there was frequent recanalization within the VO lesions, and the recanalized vessels frequently communicated with neighboring thin-walled veins in cirrhotic stroma, suggesting an intrahepatic vein to vein anastomosis. In conclusion, VO lesions, when focal, may themselves be responsible to a lesser degree for obstruction of hepatic venous outflow in liver cirrhosis.