Abstract

A case of desquamative interstitial pneumonia (DIP) has been studied by electron microscopy in order to determine the nature of the alveolar cells. Those lining the alveolar walls proved to be granular pneumocytes (type II alveolar epithelial cells) while cells free in the lumen were alveolar macrophages. The brief literature describing the electron microscopic findings in DIP is reviewed. All workers agree that the lining cells are granular pneumocytes and most report a mixed free cell population with the emphasis shifting from desquamated epithelial cells to macrophages. In the present case asbestos bodies were also found in the lung, suggesting that DIP is not a specific disease entity.