PMF lesions tend to grow very slowly, so any rapid changes in size, or development of cavitation, should prompt a search for either alternative cause or secondary disease.
[citation needed] Immunologically, disease is caused primarily through the activity of lung macrophages, which phagocytose dust particles after their deposition.
Production of inflammatory mediators – and the tissue damage that ensues as an effect of this, as well as reduced motility of cells, is fundamental to the pathogenesis of pneumoconiosis and the accompanying inflammation, fibrosis, and emphysema.
The most notable indications are the fact that the disease tends to develop in the upper lobe of the lung – especially on the right, and its common occurrence in taller individuals.
Progressive massive fibrosis increased during the period 1970–2016 among coal miners in central Appalachia who filed for black lung benefits.