Pulmonary Pathology Online
Pathology of Coal Workers' Pneumoconiosis
Simple Coal Pneumoconiosis:
Mild, predominantly distensive enlargement of respiratory bronchioles is associated with mild abnormalities of pulmonary function.
Radiologic examination shows small nodular opacities or linear opacities.
Progressive Massive Fibrosis:
Progressive massive fibrosis was first adequately described in coal miners.
The size and location of the lesions are similar to those in progressive massive fibrosis of silicosis.
The burden of silica in the lung may play a role in its pathogenesis.
The disorder is associated with significant functional disability, and there is usually an obstructive defect, which may or may not be associated with a restrictive defect.
Rheumatoid Pneumoconiosis (Caplanís Syndrome):
Caplanís syndrome was originally described in coal miners as the radiographic appearance of large lung masses together with rheumatoid arthritis.
The pulmonary lesions are large (1 cm to 10 cm in diameter), multiple, and bilateral.
Histologic examination shows them to be "rheumatoid nodules", but they differ from classic rheumatoid nodules in that the palisading of fibroblasts at the periphery is less apparent and there is necrosis with an acute inflammatory infiltrate.
Visit: Rheumatoid Nodule
Caplanís syndrome is not confined to coal miners and may occur in silicosis and asbestosis.
Pathogenesis of Coal Pneumoconiosis:
The role of silica in coal pneumoconiosis has long been controversial. Coal miners are often exposed to substantial amounts of silica, and the term antracosilicosis was widely used (Anthracite is a form of coal).
It was subsequently shown that those who worked only with coal (Example: Trimmers who loaded only coal) developed simple coal pneumoconiosis.
It has been suggested that the aggregates of coal particles in macrophages in the walls of respiratory bronchioles weaken the respiratory bronchiolar muscle, thus leading to dilatation.
It has recently been shown that the lesions in coal miners who have also been exposed to high levels of silica are different in that the silicotic nodules in the lung are heavily pigmented with coal.
In addition, progressive massive fibrosis in these subjects closely resembles conglomerate silicosis.
The frequency of coal pneumoconiosis has diminished significantly because of declines in dust levels in underground mines and the increase in strip mining.
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