Background Despite the fact that Light’s criteria remain the gold standard approach in differentiating exudates from transudates, several fluid markers have been introduced for establishing the cause of pleural effusion to differentiate types of pleural exudate. Aim The aim of this study was to explore means of discriminating between malignant and non malignant pleural effusions. Methods The study conducted on 45 patients (28-males and 17 females) with pleural effusions of different etiologies. They were classified according to their final diagnosis into four groups: Group I: 10 cases (6 males and 4 females) with tuberculous pleural effusions. Group II: 15 cases (8 males and 7 females) with malignant pleural effusions. Group III: 10 cases (7 males and 3 females) with para-pneumonic effusion. Group IV: 10 cases (7 males and 3 females) with transudative pleural effusions included as a control group. The complete biochemical analysis of pleural fluid, pleural fluid culture, and pathological examination of pleural fluid and tissue was performed. Moreover, quantitative measurement of TNF-α in serum and pleural fluid using ELISA was performed. Results Levels of TNF-α were significantly higher in the pleural fluid of exudative nature compared to transudative type. There was a significant increase in pleural fluid TNF-α level in non malignant effusions (tuberculous and parapneumonic) compared with malignant effusion. Also there was a significant increase in pleural fluid TNF-α level in tuberculous effusion versus malignant effusion. These results indicate that TNF-α may be considered a sensitive marker in differentiation between malignant and non malignant pleural effusions. Conclusion Pleural fluid level of TNF-α can be used in differentiating malignant from non malignant effusion. Also levels of TNF-α in the serum and pleural fluid could be useful as a complementary marker in the differential diagnosis of two most common types of exudates (tuberculous and malignant).
