Hilar lymphadenopathy, seen on chest x-ray or chest CT, can be classified as unilateral or bilateral, and if bilateral as symmetrical or asymmetrical. Causes Unilateral or bilateral asymmetrical Tuberculosis (“primary TB”) 
Fungal, atypical mycobacteria, viral, tularemia, anthrax Metastatic or primary hilar tumor (bronchogenic carcinoma) Lymphoma Sarcoidosis, silicosis, drug reaction Bilateral symmetrical 
Sarcoidosis—the prime diagnosis 
Viral infection (adenovirus, mononucleosis) Unilateral or bilateral asymmetrical causes can also cause bilateral symmetrical hilar adenopathy