A, B, Surgical wedge lung biopsy from patient showing respiratory bronchiolitis-like areas with pigmented (smoker’s) macrophages within the respiratory bronchioles and adjacent alveolar spaces (arrows). There is significant peribronchiolar and alveolar septal fibrosis, arguing against a diagnosis of respiratory bronchiolitis interstitial lung disease. A, Hematoxylin-eosin stain (low [40×] magnification). B, Hematoxylin-eosin stain (intermediate [100×] magnification).