Progressive massive fibrosis: An overview of the recent literature

Abstract

This review provides an overview of literature addressing progressive massive fibrosis (PMF) from September 2009 to the present. Advances are described in understanding its pathophysiology, epidemiology of the occurrence of PMF and related conditions, the impact of PMF on pulmonary function, advances in imaging of PMF, and factors affecting progression of pneumoconiosis in dust-exposed workers to PMF. Basic advances in understanding the etiology of PMF are impeded by the lack of a well-accepted animal model for human PMF. Recent studies evaluating lung tissue samples and epidemiologic investigations support an important role for the silica component of coal mine dust in causing coal workers' pneumoconiosis and PMF in contemporary coal miners in the United States and for silica in causing silicosis and PMF in artificial stone workers throughout the world. Development of PMF is associated with substantial decline in pulmonary function relative to no disease or small opacity pneumoconiosis. In recent reports, computed tomography has had greater sensitivity for detecting PMF than chest x-ray. Magnetic resonance imaging shows promise in differentiating between PMF and lung cancer. Although PMF develops in dust-exposed workers without previously identified small opacity pneumoconiosis, the presence of small opacity pneumoconiosis increases the risk for progression to PMF, as does heavier dust exposure. Recent literature does not document any effective new treatments for PMF and new therapies to prevent and treat PMF are an important need.

Keywords: Antifibrotic; Chest imaging; Coal workers' pneumoconiosis; Progressive massive fibrosis; Pulmonary function; Silicosis.

Fig. 1.

Chest radiograph of individual with PMF. Well-defined large opacity with flat margin laterally in the right upper zone. Background of small opacities present bilaterally in the upper and middle zones with minimal involvement of the right lower zone, and no involvement of the left lower zone. Arrow shows coalescence of small opacities, a precursor to formation of a large opacity, in the right middle zone (arrow). Source: CDC-NIOSH.