A hilar mass is an abnormality in one or both of the hilar lymph nodes in the lungs. It normally indicates bronchogenic carcinoma (cancer). Bronchial obstructions can appear as a hilar mass and point to a potential bronchial disease.
The size and definition of the mass helps determine if it is the primary tumor, the product of metastasis or the result of a non-cancerous enlargement of the lymph node. Inflammatory diseases such as tuberculosis and histoplasmosis can result in the enlargement of hilar lymph nodes. A CT scan is the best course for discovering the presence of a hilar mass and determining its cause.