Figures
- Figure 1.
a) Respiratory bronchiolitis: the intra-alveolar accumulation of finely pigmented macrophages (smoker’s macrophages) (haematoxylin and eosin, 400×). Generally smoker's macrophages have a strict bronchiolocentric distribution (b; haematoxylin and eosin 40×), but occasionally they involve the entire lobule (c; haematoxylin and eosin, 20×). d) Respiratory bronchiolitis in a 63-yr-old heavy smoker who was asymptomatic at the time of computed tomography. The high-resolution computed tomography image shows bilateral poorly defined centrilobular nodules in the upper lobes. e) Occasionally, particularly in desquamative interstitial pneumonia, a relatively large number of eosinophils are present and the limits with chronic eosinophilic pneumonia are sometimes blurred (haematoxylin and eosin, 200×).
- Figure 2.
Smoking-related fibrosis with dense acellular fibrosis that frequently surrounds cystic emphysematous spaces, both in a) centrilobular (haematoxylin and eosin, 40×) and b) sub-pleural parenchyma (haematoxylin and eosin, 20×). c) Specific smoking-related interstitial abnormalities in a heavy smoker with dyspnoea. A high-resolution computed tomography image showing mild ground-glass opacity and reticulation circumscribing emphysematous areas.
- Figure 3.
a) Pulmonary Langerhans’ cell histiocytosis (PLCH) is characterised by an increased number of CD1a+ Langerhans’ cells in the bronchiolar wall (200×). b) In the early/active phase of PLCH stellate cellular nodules with a bronchiolocentric distribution can be seen (haematoxylin and eosin, 10×). c) A stellate fibrotic nodule suggestive of healed PLCH is present on the left and is associated with an extensive accumulation of smoker's macrophages (haematoxylin and eosin, 20×). d) Classical example of PLCH in its mature phase consisting of multiple bronchiolocentric cellular nodules, some of which are fibrotic and irregularly cavitated (haematoxylin and eosin, 10×). e) A high-resolution computed tomography image at the level of the upper lobes showing numerous irregularly marginated bilateral nodules; a few cysts are visible. f) Chronic PLCH showing stellate scars with paracicatricial emphysema (haematoxylin and eosin, 40×).
Tables
- Table 1. Main histological lesions due to smoking and corresponding high-resolution computed tomography (HRCT) findings
Histology HRCT Smoker's macrophages within bronchiolar lumens and surrounding alveolar spaces, mild bronchiolar fibrosis and inflammation Hazy centrilobular nodules
Patchy ground-glass opacityMild distortion of bronchiolar lumens with bronchioloectasia and mucostasis Mild bronchial dilatation with wall thickening; mild air-trapping at expiratory computed tomography scanning Centrilobular and subpleural emphysema Centrilobular and paraseptal emphysema Dense interstitial fibrosis, frequently surrounding emphysematous holes Peripheral and intralobular reticulation, ground-glass opacity intermingled with emphysematous areas Increase in Langerhans’ cells forming stellate bronchiolocentric nodules, some of which are irregularly cavitated and fibrotic Ill-defined or cavitated centrilobular nodules - Table 2. Clinical features of respiratory bronchiolitis-interstitial lung disease (RB-ILD), desquamative interstitial pneumonia (DIP) and pulmonary Langerhans’ cell histiocytosis (PLCH) in comparison with combined pulmonary fibrosis and emphysema (CPFE)
RB-ILD DIP PLCH CPFE Smoking 100% 90% >90% 100% (heavy smokers) Age 3rd to 5th decade 3rd to 5th decade 3rd to 4th decade 6th to 7th decade Sex M:F Slight male dominance Nearly 2:1 1:1 Almost all male Onset Insidious Insidious Insidious Insidious Presenting symptoms Dyspnoea and cough Dyspnoea and cough Dyspnoea, cough and acute chest pain (when pneumothorax is present) Dyspnoea and cough Systemic involvement No Possible, rare Possible No Crackles ∼50% 60% Usually absent 87% basal Clubbing Rare Nearly 50% Exceptional 43% Pulmonary function Mixed defect or normal; reduced DL,CO Restrictive; reduced DL,CO Obstructive or restrictive; reduced DL,CO (especially in patients with vascular involvement) Sub-normal pulmonary volumes; severe reduction of DL,CO Pulmonary hypertension No Rare Possible 47% at diagnosis; between 50% and 90% Desaturation on 6MWT No Possible Rare Frequent Spontaneous improvement Possible Occasionally Possible No Treatment Smoking cessation Smoking cessation and steroids Smoking cessation and steroids? Smoking cessation Response to steroids Good Good Fair None Prognosis Good Good Good Poor (5-yr survival is 55%) Complete recovery possible Yes Yes Yes No Correlation with lung cancer or other neoplasms No Rare Frequent Frequent (near 50%) M: male; F: female; 6MWT: 6-min walk test; DL,CO: diffusing capacity of the lung for carbon monoxide.
