On clinical examination, crackles are common, and more rarely, patients may have clubbing (LCO). Airflow limitation is uncommon; gas exchange is usually abnormal and mild hypoxemia is common. Bronchoscopy with bronchoalveolar lavage reveals up to 40% lymphocytes, along with more subtle increases in neutrophils and eosinophils. In patients with typical clinical and radiographic features, a transbronchial biopsy that shows the pathologic pattern of<unk>  pneumonia and lacks features of an alternative diagnosis is adequate to make a tentative diagnosis and start therapy. On surgical lung biopsy, the histopathologic pattern is<unk>  pneumonia with preserved lung architecture; this pattern is not exclusive to<unk>  and must be interpreted in the clinical context. Histologically,<unk>  is characterized by the presence of polypoid plugs of loose<unk>  connective tissue (Masson bodies) within alveolar ducts, alveoli, and bronchioles.
Cryptogenic organizing pneumonia
Acute eosinophilic pneumonia
Atypical pneumonia
Allergic bronchopulmonary aspergillosis
Chronic pulmonary aspergillosis
Eosinophilic pneumonia
Parasitic pneumonia
Fungal pneumonia