Progressive massive fibrosis secondary to pulmonary silicosis appearance on F-18 fluorodeoxyglucose PET/CT

Despite adequate protective equipment, chronic exposure to free silica results in nodular lung fibrosis. Fibrosis may be progressive in the absence of further exposure, with coalescence and formation of nonsegmental conglomerates of irregular collagen containing masses characteristic of progressive massive fibrosis. Such patients have a marked increased risk of tuberculosis or atypical mycobacterial infection. Limited data on the PET appearance of pneumoconiosis has been reported. Whereas PET imaging may be useful in distinguishing benign from malignant disease in asbestos related pleural disorders, its role in the diagnosis of malignancy in the setting of pneumoconiosis with possible superimposed granulomatous infection remains unclear. PET imaging has been used to evaluate chronic inflammatory lung conditions, but usually in the setting of granulomatous processes such as sarcoidosis or mycobacterial infection.