Clinical and radiological observations on asbestos-related pathology.

The papers in this session, which are summarized briefly, do not cover the wide range of radiological and clinical problems resulting from inhalation of asbestos dust. Pleural effusions are found in persons exposed occupationally to asbestos, even in the absence of asbestosis, but they are difficult to attribute to such exposure. Asbestosis of the lung shows no striking symptoms and can also be diagnosed only after all other possibilities have been excluded. There are no convincing or striking morphological peculiarities that suggest that an 'asbestos lung cancer' exists. Mesotheliomas of the pleura and of the peritoneum are usually resistant to therapy of any kind, although several possibilities are discussed. Radiological surveillance is presented as being still the most effective and reliable method for medical surveillance of asbestos workers. Circumscribed pleural thickening is benign but a good indicator of exposure to mineral dusts. Diffuse pleural thickening occurs frequently in nonexposed groups and cannot, therefore, be used as an indication of exposure; however, it cannot yet be ruled out as being significant epidemiologically.