Absence of carcinoembryonic antigen-like material in mesothelioma: an immunohistochemical differentiation from other lung cancers.

This study is to examine the potential usefulness of immunohistochemical staining for carcinoembryonic antigen (CEA)-like material in the differential diagnosis of mesotheliomas (12 cases) from other lung cancers (14 cases) that had been previously diagnosed by transmission and scanning electron microscopy and conventional light microscopy. Indirect immunofluorescent staining for CEA was carried out on formalin-fixed paraffin-embedded sections, and the slides were examined under code. All 9 cases of diffuse mesothelioma were negative, and all 12 cases of adenocarcinoma and bronchioloalveolar carcinoma were positive for CEA-like material. Three localized mesotheliomas and a carcinoid tumor were also negative. A squamous cell carcinoma was positive. A positive immunohistochemical result for CEA-like material in lung cancers will raise the possibility of its being of bronchial epithelial origin.