US EPA

3101339 

Technical Report 

The Pathology Of Asbestosis 

Webster, I 

1972 

NIOSH/00156071 

Rogan 

39-55 

The pathology of asbestosis is reviewed. Fibrogenic parameters of asbestos (1332214) dusts are discussed. Asbestotic fibrosis is described. Asbestosis has been regarded as an interstitial fibrosis in which the walls of the lower respiratory tract are thickened. Although the role of long and short fibers in the development of asbestotic parenchymal fibrosis has been established, the relationship of these to the observed chronic pleurisy and pleural plaques has not been elucidated. The predominating fibrosis has been found to be intraalveolar and not in the walls of the air spaces. Basal asbestosis is examined. Chronic pleurisy arising from asbestos exposure is described. The classification of asbestosis is summarized. Some countries classify asbestosis into three grades, slight, moderate, or marked, depending on the degree of interstitial fibrosis and the extent of parenchymal involvement. Asbestotic plaques are reviewed. Plaque formation may be the result of a sensitization reaction. Malignant tumors associated with asbestos exposure are discussed. Epidemiologic studies of the incidence of bronchogenic carcinoma among individuals occupationally exposed to asbestos are mentioned. The incidence of mesothelioma among asbestos workers and miners is noted. Epidemiologic studies of the incidence of mesothelioma among asbestos miners in South Africa are described. It is suggested that in addition to asbestos, some other factor is necessary for the development of mesothelioma. The histological features of mesothelioma are reviewed.