Lung, Silicosis

Silicosis is currently the most prevalent chronic occupational disease in the world. Patients usually present decades after inhalation of crystalline silicon dioxide with a slowly progressing, nodular, fibrosing pneumoconiosis. After inhalation, the particles are phagocytosed by macrophages, leading to the release of inflammtory mediators. In its early stage, silicosis is characterized by tiny, discrete pale to blackened nodules in the hilar lymph nodes and upper zones of the lungs. As the disease progresses, the silicotic nodules coalesce into hard, collagenous scars and may produce progressive massive fibrosis. The disease may continue to worsen even if the exposure is removed.

This section of the lung shows multiple hyalinized nodules in a bronchovascular distribution, with coalescent scars and extensive fibrosis of the lung parenchyma.