Features of nonfibrotic smoking-related interstitial lung disease
| Respiratory bronchiolitis | Respiratory bronchiolitis interstitial lung disease | Desquamative interstitial pneumonia | Pulmonary Langerhans cell histiocytosis | |
|---|---|---|---|---|
| Zonal distribution | Upper lobe | Upper lobe | Lower lobe (60%) Diffuse (20%) Patchy (20%) | Upper lobe (spares the costophrenic angles) |
| Clinical findings | Absent | Cough and dyspnea | Cough and dyspnea | Cough and dyspnea, constitutional symptoms (1/3 of patients) and pneumothorax (15%) |
| Findings on high-resolution computed tomography | Poorly defined centrilobular ground-glass nodules | Poorly defined centrilobular ground-glass nodules Patchy ground-glass opacities Bronchial wall thickening Reticulation occasionally (no traction bronchiectasis or honeycombing) | Ground-glass opacity (widespread, bilateral and symmetrical in 86%) Reticular opacities (59%) Traction bronchiectasis Honeycombing is uncommon (< 1/3 of patients) | Cysts: bizarrely shaped and nonuniform in size Nodules: irregular or cavitary, centrilobular and peribronchial in location |
| Associated features | Centrilobular emphysema Air-trapping | Centrilobular emphysema Peripheral cystic spaces (dilated bronchioles and alveolar ducts) | ||
| Characteristic image | Figure 1 | Figure 2 | Figures 3 and 4 | Figures 5–8 |
| Typical clinical course | Usually asymptomatic; may progress to respiratory bronchiolitis-interstitial lung disease if smoking continues | Cough and progressive dyspnea on exertion | Cough and progressive dyspnea; can progress despite smoking cessation | Fever, weight loss, nonproductive cough, dyspnea, chest pain; spontaneous pneumothorax also seen |
| Role of lung biopsy | None | None | Surgical lung biopsy may be indicated if diagnosis is uncertain | Surgical lung biopsy may be indicated if diagnosis is uncertain |