[High Ca 125 serum level in benign ascites or pleural effusion].

In 26 patients with benign and 44 patients with malignant ascites or pleural effusion the levels of the tumour marker Ca 125 were determined in the effusion and in the serum. No significant differences between both groups were seen. Values exceeding the tenfold level of the upper standard limit were often found even in patients with benign and non-carcinomatous malignant diseases. This is probably due to a production of the antigen even in benign proliferating cells of the mesothelium. Enhanced Ca 125 serum levels cannot therefore be interpreted as indicating the presence of an (ovarian) carcinoma if there is an ascites or pleural effusion; they can also be an expression of a proliferation of the mesothelium in benign processes of other organs.