Controversies and uncertainties concerning the pathologic features and pathologic diagnosis of asbestosis

Asbestos is a fibrous silicate mineral that has been known for decades to cause pulmonary scarring, referred to as asbestosis. The simplest definition of asbestosis is the presence of pulmonary fibrosis as a result of accumulation of airborne asbestos in the lungs. Not infrequently, the terms "asbestos" and "asbestosis" are used incorrectly (interchangeably) by medical personnel, and sometimes pleural fibrosis caused by asbestos is incorrectly referred to as asbestosis. The earliest lesion of asbestosis, as defined by the CAP-NIOSH Committee is peribronchiolar fibrosis, although controversy exists as to how specific this lesion is with respect to causation by asbestos, and whether this lesion progresses to grade 4 asbestosis. In addition, some authorities in the field suggest that the term "asbestosis" be used only for diffuse interstitial fibrosis. The mechanism by which asbestos causes interstitial fibrosis remains poorly understood, and in recent years, pathologic changes such as organizing pneumonitis-bronchiolitis obliterans, and lymphocytic interstitial pneumonitis, have been described in persons occupationally exposed to asbestos, suggesting that the pulmonary lesions caused by asbestos represent a wider spectrum than had previously been appreciated. By defining areas of uncertainty, medical science will eventually clarify areas of disagreement concerning asbestosis which will eventually lead to a better understanding of this disease.