[Three cases of respiratory bronchiolitis-associated interstitial lung disease (RB-ILD): a study of HRCT-pathologic...

Respiratory bronchiolitis-associated interstitial lung disease (RB-ILD) is a clinicopathologic entity occurring rarely in smokers. We report three cases of RB-ILD diagnosed pathologically by surgical lung biopsy. Cough was observed in all cases, sputum in one case and dyspnea on exertion in another. Reduction of diffusing capacity was observed in all three cases. No abnormality was found in the chest radiographs of any case. However, in high-resolution computed tomography (HRCT), ground-glass opacities and centrilobular nodules were observed in all three cases, emphysema in one case, intralobular linear or reticular opacities in two cases, small subpleural cysts in two and emphysema in one. Histologic examination of lung biopsy specimens taken by thoracoscopy showed peribronchiolar fibrosis and centrilobular intraluminal accumulation of macrophages in all three cases, centrilobular emphysema, membranous bronchioles filled with mucus and macrophages, and focal microscopic honeycombing in subpleural lesions in one case each. RB-ILD should be included in the differential diagnosis of interstitial lung disease in smokers.