Abnormal pulmonary thoracic imaging finding Progressive massive fibrosis 2021-03-31T10:46:55Z This condition is caused by slow-growing conglomeration of dust particles and collagen deposition in individuals (mostly coal workers) heavily exposed to inorganic dust. Progressive massive fibrosis manifests as masslike lesions, usually bilateral and in the upper lobes. Background nodular opacities reflect accompanying pneumoconiosis, with or without emphysematous destruction adjacent to the massive fibrosis. Lesions similar to progressive massive fibrosis sometimes occur in other conditions, such as sarcoidosis and talcosis. See Figure 56 of Hansell DM, et al., Fleischner Society: glossary of terms for thoracic imaging. Radiology. 2008;246:697-722.