Coal Worker's Pneumoconiosis

The pathologic hallmark of CWP is the coal macule, which is a focal collection of coal dust surrounded by relatively little cellular infiltration or fibrosis (Fig. 10.3). The initial lesions tend to be distributed primarily around respiratory bronchioles. Small associated regions of emphysema, termed focal emphysema, may be seen.

As with silicosis, the disease is often separated into simple and complicated forms. In simple CWP the chest radiograph consists of relatively small and discrete densities that usually are more nodular than linear. In this phase of the disease, patients have few symptoms, and pulmonary function usually is relatively preserved. In later stages of the disease, to which only a small minority of individuals progress, chest radiographic findings and clinical symptoms are more pronounced. With extensive disease and coalescent opacities on chest radiographs, patients are said to have complicated CWP, also called progressive massive fibrosis. Pulmonary function may show restrictive disease, obstructive disease, or a mixed pattern, depending upon the relative amounts of fibrosis, airways disease, and emphysema.