No abstract

The usefulness of the determination of carcinoembryonic antigen (CEA) in pleural effusion was assessed as an aid to the diagnosis of malignant mesothelioma. The concentration of CEA was determined by radioimmunoassay (RIA) in pleural fluid of 213 adult patients, of which 140 had malignant pleural disease and 73 had nonmalignant pleural disease. Pleural fluid CEA (PF CEA) was lower than 12 ng/ml in all 15 mesotheliomas. The statistical probability of a mesothelioma associated with PF CEA greater than 15 ng/ml was found to be zero. The CEA assay in pleural effusion proved to be a valuable adjunct to other diagnostic procedures in differentiating the malignant mesothelioma from metastatic serosal spread. Cancer 53:1194‐1197, 1984.

The usefulness of tumor marker assay in pleural effusions for differential diagnosis is still debated. From the observation of common antigens on tissue polypeptide antigen (TPA) and keratins 8, 18 and 19 and vimentin, all substances contained in normal and neoplastic mesothelium, we felt it opportune to evaluate the use of TPA assay in 105 pleural effusions (46 benign and 59 malignant). The values were much higher than those found in blood. In hydrothorax the median value was 454 U/l (range, 59-1923), in exudative effusions 846 U/l (range, 258-4485), in metastatic pleural effusions 1277 U/l (range, 58-32352) and in mesotheliomas 7705 (range, 759-16000). The maximum value found in nonmalignant effusions was 4485 U/l; this value was taken as a cutoff level, so only 29.9% of the tumors were positive to the test. Our results showed this assay to be not very important for a differential diagnosis of malignant and nonmalignant pleural effusions. Nevertheless, the different TPA patterns in mesotheliomas (66.6% positive) and metastatic pleural effusions (15.9%) suggest that further studies are warranted.