Focal veno-occlusive lesions following metastasis of cancer in the liver with special reference to obstruction of lymphatics in hepatic veins.

Focal veno-occlusive lesions and congestion of the liver are found frequently at autopsy in patients with metastatic carcinoma in the liver. In 6 cases, intimal proliferation of loose connective tissue with dilatation of lymphatic capillaries was seen continuously from the terminal hepatic venule to the hepatic vein, and cancer cells were found only in lymphatic capillaries in the wall of the hepatic vein. In 7 cases, cancer cells infiltrated directly into the adventitia of the sublobular vein and intimal proliferation of loose connective tissue with or without formation of recent thrombi was observed. A main causative factor of hepatic veno-occlusive disease is thought to be leakage of plasma due to endothelial injury to the terminal hepatic venule and sublobular vein. Lymphatic obstruction, in addition to a direct reaction to invasion of cancer cells to the vessel wall, may also cause veno-occlusive lesions due to stasis and leakage of lymph fluid into the intima of the terminal hepatic venule, sublobular vein and hepatic vein.