Detection of benign or malignant origin of ascites with combined indirect immunoperoxidase assays of carcinoembryonic antigen and lysozyme.

The indirect immunoperoxidase method was used to study the presence of the intracellular carcinoembryonic antigen (CEA) and lysozyme (LZ) in alcohol-fixed cytologic smears of peritoneal fluids from 2 patients with chronic active hepatitis, 31 patients with liver cirrhosis and 7 patients with malignant liver disease. In the two patients with hepatitis, LZ was positive in both CEA was positive in one and negative in the other. Of the 31 patients with liver cirrhosis, 21 (67.5%) were LZ positive, 27 (87%) were CEA negative and only 4 (13%) were CEA positive. Of the seven patients with malignant disease, six were CEA positive and six were LZ negative. It is of interest that 23 of 24 (96%) LZ-positive results and 28 of 29 (97%) CEA-negative results corresponded to negative cytologic diagnoses for malignancy. Cytologic diagnosis of "reactive mesothelial cells" seemed to correlate better (71%) with CEA-negative and LZ-positive results. The data suggest that the investigation of CEA and LZ in the cells of peritoneal fluids appears to have promise as an adjunct to cytology in differentiating benign from malignant origins of the fluid.

The cytologic application of carcinoembryonic antigen for the discrimination of malignant from benign serous effusions.

In an attempt to diminish false cytologic diagnosis in discriminating between benign and malignant effusions, the value of intracellular carcinoembryonic antigen (CEA) was estimated in cytologic smears of effusions using a modified immunoperoxidase technique. CEA serum level was estimated by radioimmunoassay technique. In this study we included a group of 42 patients, 23 with a malignant and 19 with a benign effusion. CEA in cells of effusions was positive and useful for confirming malignancy in 65% of malignant effusions. The percentage increased to 83% with the combination of the results of positive CEA in cells and serum. Cytology was positive for malignancy in 16 of the 23 (70%) malignant cases. CEA in cells of benign effusions was negative in 84% and cytology in 100%. It is concluded that intracellular CEA estimation, when combined with CEA estimation in serum, improves the discriminating range of cytology for differentiating malignant and benign effusions.