Lung fibrosis induced by Thorotrast.

A 63 year old woman developed progressive shortness of breath, pulmonary hypertension, and respiratory failure and died from pulmonary fibrosis 45 years after thoracic fistulography with Thorotrast. Bouts of acute respiratory failure occurred with features of noncardiogenic pulmonary oedema. Lung tissue obtained by biopsy and at necropsy showed abundant radioactive particles of thorium dioxide in the lungs. The particles were congregated in the walls of blood vessels and in perivascular fibrous zones, consistent with a causal role of Thorotrast in the development of lung fibrosis. It is suggested that the fibrosis was due to the combined effects of alpha radiation on the interstitial perivascular zones and of recurrent pulmonary oedema due to endothelial damage.