Desquamative interstitial pneumonia: relationship to interstitial fibrosis.

, , 680-693. The clinical course and radiographic and pathological findings in 14 patients having the histological pattern of desquamative interstitial pneumonia (DIP) have been studied. Four deaths occurred from cardiorespiratory failure and two from other diseases, and one patient has severe pulmonary insufficiency. Seven patients had altered immunological reactivity or arthritis. Necropsy of three patients, one who died of respiratory insufficiency and two of other diseases, revealed diffuse pulmonary fibrosis with loss of the desquamative features noted on biopsy. One patient had had industrial exposure to tungsten carbide dust and -ray diffraction analysis of the post-mortem lung showed high concentrations of this substance. Ultrastructural observation and direct immunofluorescent staining of one specimen demonstrated fibrin in the alveolar space, a feature usually regarded as distinguishing DIP from chronic fibrosing interstitial pneumonia. Our clinical and pathological observations suggest that the histological pattern recognized as DIP may be a non-specific reaction to diverse forms of injury, which is not clearly separable from the usual type of diffuse interstitial fibrosis.