Desquamative interstitial pneumonia: an analytic review with an emphasis on aetiology

Abstract

Desquamative interstitial pneumonia (DIP) is characterised by the accumulation of numerous pigmented macrophages within most of the distal airspace of the lung and, sometimes, the presence of giant cells. Diagnosis of DIP is not easy and requires surgical lung biopsy. DIP is usually associated with tobacco smoke. However, the association between smoking and DIP is less robust than that with respiratory bronchiolitis with interstitial lung disease or pulmonary Langerhans' cell histiocytosis; approximately 10-42% of patients with DIP are nonsmokers. DIP can also occur in patients following exposure to certain inhaled toxins (occupational exposure) and drugs, and may occur in the context of certain viral illnesses and autoimmune diseases. In the context of DIP, occupational exposure should be systematically investigated.

Keywords: Giant cell; interstitial lung disease; macrophages; occupational lung disease; surgical lung biopsy; tobacco.

Figure 1.

Example of thin parenchymal section computed tomography findings in desquamative interstitial pneumonia: patchy ground-glass attenuation with a peripheral bilateral and almost symmetric distribution, and irregular and linear opacities.

Figure 2.

a–c) This lung biopsy from a 55-year-old male patient, who was a nonsmoker, shows a typical desquamative interstitial pneumonia pattern. Tissue sections show a) diffuse involvement of the lung by intense macrophage accumulations within almost all of the distal airspace, b) without significant thickening of alveolar septa and sparse inflammatory infiltrate (*). Macrophages do not contain dusty pigment. c) Immunohistochemical analysis with CD163 antibody shows the macrophage nature of the cells. d–f) Lung biopsy from a 66-year-old female, who was a heavy smoker, showing a respiratory bronchiolitis/interstitial lung disease pattern. d) Macrophage accumulation is diffuse but predominantly peribronchiolar and f) in respiratory bronchioles. Alveolar septa are slightly thickened. e) The cytoplasm of most macrophages contains an abundant dust-brown pigment.