Definition
Pneumoconioses is a group of diseases characterized by a diffuse fibrotic reaction in the lungs induced by inhalation of organic or inorganic particulate matter and chemical fumes and vapors. The pathogenesis of the fibrosis is through the release of fibrogenic chemical mediators. (Refer to Table 15-8 in your textbook).

Pathology
Although the end-point is fibrosis, the pattern and location varies with the type.

• Coal Workers' Pneumoconiosis: The pathology ranges from anthracosis (carbon deposited in lung macrophages and lymphatics) to progressive massive fibrosis. The fibrosis occurs primarily in the upper zones of the lungs. (Refer to Figure 15-25 in your textbook).
• Silicosis: Silica is ingested by macrophages. The activated macrophages release powerful chemical mediators like interleukin-1 and tissue necrosis factor which cause fibrosis. nodular fibrosis and larger, dense scars occur primarily in the upper zones of the lung. Silica is present in the nodules. (Refer to Figures 15-29 and 15-30 in your textbook).
• Asbestosis
  1. The primary pathology in the lung is diffuse interstitial fibrosis which early on predominates in the lower zones of the lungs. The asbestos body is a unique feature of this type of fibrosis. (Refer to Figure 15-31 in your textbook).
  2. Pleural plaques (circumscribed areas of fibrosis) are the most common manifestation of asbestosis.
  3. High incidence of mesothelioma and bronchogenic carcinoma.
• Berylliosis: Beryllium induces cell-mediated immunity resulting in non-caseating granulomas scattered throughout the lungs and hilar lymph nodes. The granulomas "burn out," becoming fibrotic and forming fine nodular densities throughout the parenchyma.