The pneumoconioses are a group of diseases characterized by lung parenchymal changes due to inhalation of inorganic dusts. The exposures causing these diseases most frequently occur in occupational settings. Included among the pneumoconioses are asbestosis, silicosis, silicatosis, mixed pneumoconiosis, mixed dust pneumoconiosis, coal worker’s pneumoconiosis, siderosis, aluminosis, and giant cell interstitial pneumonia/hard metal pneumoconiosis. Detailed discussions of these entities are beyond the scope of this book.

Many more individuals are exposed to inorganic dusts than develop disease from the exposure, and all of these individuals are potentially susceptible to other types of unrelated lung disease. Therefore, the gold standard for the diagnosis of a pneumoconiosis is a tissue sample that is sufficiently large enough to avoid the sample restrictions of a limited transbronchial biopsy. However, transbronchial biopsies may provide potentially useful evidence of a particular exposure without providing sufficient material by themselves for the diagnosis of disease: Asbestos bodies indicate exposure to asbestos, but there is insufficient tissue in a transbronchial biopsy to quantify the exposure or assess the presence of diffuse interstitial fibrosis characteristic of the disease asbestosis. Other findings that may be seen on transbronchial biopsy that indicate an exposure but do not permit definitive diagnosis of a pneumoconiosis by themselves include coal dust macules, multinucleated giant cells within alveolar spaces (hard metal pneumoconiosis), and early silicotic nodule with dust-laden macrophages and tiny, weakly birefringent silica particles on polarization. Although the transbronchial biopsy can potentially convey some information about exposure, it is simply too small a sample to provide a definitive diagnosis of a pneumoconiosis or to rule out a pneumoconiosis if apparently negative. Correlation of findings on a transbronchial biopsy with clinical and radiologic findings may be helpful, if a larger biopsy is not clinically indicated.