Malignant mesothelioma ofthepleura: relation between histological typeandclinical behaviour

Thediffering clinical behaviour ofmalignant mesothelioma ofdifferent cell typeswas studied in115casesofpleural mesothelioma, classified histologically intoepithelial (60), sarcomatous (25), andmixed(30). Epithelial mesotheliomas were associated withclinical features characteristic ofcarcinomas rather than sarcomas,including spread oftumourbydirect extension, large pleural effusions, contralateral pleural effusions, ascites, metastases inregional lymphnodes, andoccasional responsetoradiotherapy. Sarcomatous mesotheliomas were associated with clinical features more characteristic ofsarcomas,with more frequent distant metastases, little orno effusion, andshorter survival. Mixedtumourshadfeatures ofboth,large pleural effusions occurring as frequently as withepithelial tumours,butsurvival beingalmost as poor as in sarcomatous cases.Despite thesedifferences thereisevidence frompublished reportsthat epithelial, sarcomatous, andmixedmesotheliomas have acommon origin frommesothelial cells or their precursorcells.