They were asked to classify the histopathologic pattern according to the 2002 ATS/ERS statement on IIP (1) as follows: UIP, nonspecific interstitial pneumonia, organizing pneumonia, diffuse alveolar damage, respiratory bronchiolitis,
desquamative interstitial pneumonia, and other specific diseases.
Given that most patients with PLCH are smokers, it is not surprising that the background lung parenchyma might show smoking-related changes including respiratory bronchiolitis,
desquamative interstitial pneumonia, and/or emphysema (Figures 2, B, and 4, E).
As described and referenced in the preceding paragraphs, the histologic appearance of lung injury secondary to cigarette smoke is a constellation of findings that includes smokers' macrophages within airspaces, which may be airway centered (respiratory bronchiolitis) or diffuse (
desquamative interstitial pneumonia) in distribution; emphysema; small-airway injury evidenced by submucosal and adventitial fibrosis, remodeling that results in distortion, and increased bronchus-associated lymphoid tissue; thickening of walls of small arteries and arterioles; stellate cellular and/ or fibrotic lesions of pulmonary Langerhans' cell histiocytosis; and alveolar wall fibrosis (Figure, c through g).
(4) The purpose of this short article is to suggest how RBF fits into the general category of smoking-related ILD, and particularly to compare it with two possibly related forms of accepted smoking-related ILDs: respiratory bronchiolitisinterstitial lung disease (RBILD) and
desquamative interstitial pneumonia (DIP).