Abstract

An unequivocal diagnosis of mesothelioma during life, on the basis of limited biopsy tissue or cytological specimens, is frequently difficult and requires distinction from inflammatory mesothelial hyperplasia on the one hand and secondary neoplasms, especially adenocarcinoma on the other. Although some studies have produced conflicting results, it is generally believed that immunohistochemical methods can aid in this distinction. To obtain comparable and reproducible results, 23 metastatic carcinoma of the pleura and 2 unequivocal malignant epiehtlial mesotheliomas were studied by the peroxidase-antiperoxedase method on paraffin-embedded cell blocks, and commercially available antibodies to carcinoembryonic antigen (CEA), keratin and epithelial membrane antigen (EMA) were used. Nineteen metastaic adenocarcinoma (73%) and two mesotheliomas (100%) reacted with keratin and EMA antibodies. Nineteen matastatic adenocarcinomas (73%) reacted with EMA antibodies. Nineteen metastatic adenocarcinoma (73%) reacted with CEA antibody; no mesotheliomas stained for CEA. Two cases of reactive mesothlial hyperplasia showed positive for keratin, but negative reaction for EMA and CEA. Noen of the antibodies used in this study was specific for mesothelioma, but CEA was found to be the most useful marker for differentiating between mesothelioma and metastatic carcinoma.

• Keywords: Immunocytochemistry;Pleural effusion;