May Be Caused by

 Common

Alveolar proteinosis

Bronchiolitis obliterans with organizing pneumonia

Bronchiolo-alveolar carcinoma

Desquamative interstitial pneumonitis

Lymphocytic interstitial pneumonitis

Lymphoma

Nonspecific interstitial pneumonitis

Obstructive pneumonia

Recurrent pneumonia

Sarcoidosis

 Uncommon

Alveolar microlithiasis

Aspergillosis

Atypical mycobacterial infection

Choriocarcinoma

Chronic eosinophilic pneumonia

Fungal disease

Hemorrhagic lung metastasis

Intralobar pulmonary sequestration

Lipoid pneumonia

Mineral oil aspiration

Silicoproteinosis

Tuberculosis