Study Syllabus for Classification of Radiographs of Pneumoconioses

Pathology Overview

Pathology Basis of Occupational Lung Disease

Coal Workers’ Pneumoconiosis

Associated Lesions: Emphysema and Diffuse Interstitial Fibrosis

Inhalation of coal mine dust has been determined to be an independent risk factor in the development of emphysema [Green and Vallyathan 1998; Cockroft et al. 1982; Ruckley et al. 1984b]. Progressive centrilobular emphysema constitutes an extension of focal emphysema associated with the coal macule. Panacinar emphysema represents a less common variant associated with coal dust exposure.

In a study that evaluated emphysema severity in whole-lung thick sections from autopsies of 616 US coal miners and 106 non-miners performed from 1957 to 1973, Kuempel et al found that emphysema was significantly elevated in coal miners compared with non-miners regardless of smoking history. Additionally the study reported that cumulative exposure to respirable coal mine dust and coal dust retained in the lungs were significant predictors of emphysema severity [Kuempel et al. 2009].

Pulmonary interstitial fibrosis documented at autopsy has been variably reported in the lungs of coal miners in as many as 33% of cases. Interstitial fibrosis may macroscopically resemble honeycomb lung. Histologically, black pigment and mineral deposition in the areas of interstitial fibrosis were noted in 53% of cases (Fig. 31). However, in the remaining 47%, interstitial fibrosis was nonpigmented, resembling the type of fibrosis seen in idiopathic pulmonary fibrosis [McConnochie et al. 1988]. Chronic interstitial pneumonia and fibrosis resembling usual interstitial pneumonia were also identified in a subset of French coal miners with clinical and radiologic evidence of interstitial lung disease with honeycombing [Brichet et al. 2002].