[A case of desquamative interstitial pneumonia in the fibrotic stage].

A 39-year-old man with bronchial asthma was admitted because of fever, muscle pain and body weight loss. Chest CT showed ground-glass opacification, multiple lung cysts and fine reticulation with traction bronchiectasis predominantly in the bilateral lower lobes. Histopathological findings from video-assisted thoracoscopic surgical biopsy showed severe fibrosis of the alveolar wall, interstitial fibrosis which appeared to be of similar duration, and accumulation of eosinophils and macrophages in the alveolar spaces. According to the ATS consensus classification of desquamative interstitial pneumonia (DIP), there is little fibrosis with only mild or moderate thickening of alveolar walls and no scarring fibrosis causing remodeling of the lung architecture. This case was compatible with the ATS consensus classification of desquamative interstitial pneumonia (DIP) without severe fibrosis of the alveolar wall. Finally, we diagnosed DIP in the fibrosing stage because the findings of chest CT were typical and the pathological findings showed the presence of increased amounts of cuboidal epithelium hyperplasia and intraalveolar acidophilic macrophages within a part of moderate interstitial fiblosis. Then we started orally corticosteroid therapy, and as a result he responded well.