Disease category | Examples | Findings in BAL fluid |
Malignancy | Lymphangitic carcinomatosis | Malignant cells |
Bronchioloalveolar cell carcinoma | Malignant cells |
Pulmonary lymphoma | Malignant cells |
Diseases due to inhaled (exogenous) material | Lipoid pneumonia | Fat globules in macrophages (oil-red-O-stain) |
Multinucleated giant cells |
Asbestosis | Ferruginous bodies |
Silicosis | Dust particles seen by polarized microscopy |
Berylliosis | Positive lymphocyte transformation test to beryllium salts |
Inflammatory | Diffuse alveolar hemorrhage | Large numbers of erythrocytes |
Hemosiderin-laden macrophages (iron stain) |
Sequential lavages progressively more hemorrhagic |
Chronic eosinophilic pneumonia | Eosinophils ≥40 percent |
Idiopathic acute eosinophilic pneumonia | Eosinophils ≥25 percent |
Pulmonary alveolar proteinosis | Lipoproteinaceous material (periodic acid-Schiff stain) |
Pulmonary Langerhans cell histiocytosis (Histiocytosis X) | Monoclonal antibody (T6) positive histiocytes |
CD1 positive Langerhans cells >5 percent |
Birbeck granules in lavaged macrophages (seen by electron microscopy) |