Massive pleural effusion and marked increase of CA-125.

The tumour associated CA-125 antigen is widely used in monitoring ovarian carcinoma. In women with a massive pleural effusion and ascites, markedly increased CA-125 levels may lead to an erroneous diagnosis of ovarian cancer. Very high levels of tumour markers may be present in patients with benign pleural effusion, ascites, and chronic liver disease. Raised levels of tumour markers in serum or pleural fluid, in the absence of positive cytology, should be interpreted with caution.