ABSTRACT
Thirty patients with pleural effusions; 15 with malignant effusion and 15 with nonmalignant effusion were studied. Liver function tests were normal in both groups of patients. Pleural fluid total white count, lymphocytes and polymorphonuclear cells were significantly higher in nonmalignant than malignant groups, while pleural fluid protein content in malignant group was more often in the range of concentrations found in nonmalignant group. This showed that the rise in protein content of pleural fluid is not specific and can not discriminate malignant form nonmalignant pleural effusion. Fibronectin [FN] and cholesterol contents in malignant pleural effusion were significantly higher than nonmalignant pleural effusion. Also, pleural fluid FN in malignant group was higher than its serum level. No correlation was found between the pleural fluid FN and its serum level in both groups which shows that pleural fluid FN is not only due to simple exudation from plasma, and it may be in part produced locally. No correlation was found between pleural effusion FN and cholesterol and the protein content in both groups of patients. A good positive correlation was found between pleural effusion FN and cholesterol content in malignant group. So, this work showed that the measurement of pleural effusion FN offers a good discrimination and a higher differential diagnostic efficiency for malignant effusion superior to the conventional protein determination