Malignant causes | Lymphoma and other lymphoid neoplasms (eg, Hodgkin and non-Hodgkin lymphoma, Castleman's disease, multiple myeloma, Angioimmunoblastic T cell lymphoma) | Leukemia (eg, acute lymphoblastic leukemia) | Metastatic cancer (eg, lung, esophagus, gastrointestinal, breast) | Lymphangitis carcinomatosis | Kaposi sarcoma | Lymphosarcoma | Non malignant lymphoid disorders (eg, lymphoid histiocytosis) | | Benign | Infectious | Mycobacterial disease – M. tuberculosis, atypical mycobacterium | Fungal infection – histoplasmosis, coccidioidomycosis | Infectious mononucleosis (Epstein Barr virus) | Human immune deficiency virus | Pulmonary anthrax (Bacillus anthracis) | Bacterial abscess (eg, actinomycosis) | Tularemia (Francisella tularensis) | Inflammatory | Sarcoidosis | Rheumatoid arthritis | Systemic sclerosis | Systemic lupus erythematosus | Whipple's disease | Cystic fibrosis | Hypersensitivity pneumonitis | Pneumoconiosis (coal, beryllium, silica, asbestos) | Lymphomatoid granulomatosis | Rosai-Dorfman disease | Amyloidosis | Reactive | Local infection (eg, pneumonia, pharyngitis) | Pulmonary edema | Mediastinal hematoma | |