Ultrastructure of diffuse malignant mesothelioma of the pleura. An analysis of ten cases.

An electron-microscopic examination of ten cases of malignant pleural mesothelioma is presented. The most characteristic features for diagnosis are: presence of microvilli and desmosomes, abundant intermediate filaments and direct contact between microvilli and collagen fibres. Microvilli were present not only on the luminal surface of the cells, but also on the abluminal surfaces. Differentiation towards the cells characteristic for rhabdomyosarcoma was found in one case.