BACKGROUND: Hepatic catalase activity is decreased in patients with malignant diseases, but little is known about the organelles that contain the bulk of catalase: the peroxisomes. METHODS: The authors studied the hepatocellular peroxisomes in patients with malignant diseases by means of catalase cytochemistry, light and electron microscopic study, and morphometry. RESULTS: Under the light microscope, a decrease in catalase staining was observed in 21 of 39 patients with extrahepatic tumors. A peculiar perinuclear concentration of peroxisomes was seen by light microscopic study in 15 of 39 patients and reflected an increase in number in most patients. In one of two hepatoma livers, peroxisomes also showed this perinuclear configuration. Ultrastructural and morphometric analysis of 20 livers of patients with extrahepatic tumors revealed a decreased mean peroxisomal diameter and an increase in number. Electron microscopic study also showed peroxisomes with transparent matrical spots, cytoplasmic invaginations, protrusions, and gastruloid cisternae. In each liver, at least one of these changes was observed. In hepatoma livers, one-third of the peroxisomes revealed empty matrical spots. In one patient, peroxisomes were smaller but more numerous. CONCLUSIONS: Alterations of the peroxisomal compartment are constant findings in the livers of patients with malignant diseases, but individual differences in peroxisomal alterations are frequent.
BACKGROUND: Hepatic catalase activity is decreased in patients with malignant diseases, but little is known about the organelles that contain the bulk of catalase: the peroxisomes. METHODS: The authors studied the hepatocellular peroxisomes in patients with malignant diseases by means of catalase cytochemistry, light and electron microscopic study, and morphometry. RESULTS: Under the light microscope, a decrease in catalase staining was observed in 21 of 39 patients with extrahepatic tumors. A peculiar perinuclear concentration of peroxisomes was seen by light microscopic study in 15 of 39 patients and reflected an increase in number in most patients. In one of two hepatoma livers, peroxisomes also showed this perinuclear configuration. Ultrastructural and morphometric analysis of 20 livers of patients with extrahepatic tumors revealed a decreased mean peroxisomal diameter and an increase in number. Electron microscopic study also showed peroxisomes with transparent matrical spots, cytoplasmic invaginations, protrusions, and gastruloid cisternae. In each liver, at least one of these changes was observed. In hepatoma livers, one-third of the peroxisomes revealed empty matrical spots. In one patient, peroxisomes were smaller but more numerous. CONCLUSIONS: Alterations of the peroxisomal compartment are constant findings in the livers of patients with malignant diseases, but individual differences in peroxisomal alterations are frequent.