Enlarged lymph nodes in the left hilar region are not necessarily lung cancer; enlarged hilar lymph nodes can also be seen in tuberculosis, nodular disease, lymphoma and other conditions. 1. Lung cancer: Lymphatic metastasis is the most common metastatic route for lung cancer cells. Cancer cells pass through the lymphatic channels around bronchial tubes and pulmonary blood vessels, first invade into peribronchial lymph nodes of neighboring lung segments or lobes, and then metastasize to hilar lymph nodes, which can be seen as enlarged hilar lymph nodes in imaging examination. 2. Tuberculosis: Mycobacterium tuberculosis in the primary lesion of tuberculosis is drained to the hilar lymph nodes through the intrapulmonary lymphatic tracts, thus causing enlargement of the hilar lymph nodes. 3. Nodular disease: Nodular disease is a granulomatous disease of unknown origin that mainly invades the lungs and lymphatic system. Bilateral enlargement of hilar lymph nodes is the most common chest imaging sign of nodal disease. 4. Lymphoma: Lymphoma mainly invades the lymphatic system throughout the patient’s body. In this disease, patients may also present with enlarged hilar lymph nodes. For patients with enlarged hilar lymph nodes, they should go to the relevant departments of regular hospitals for consultation, and the physicians will take into account the patient’s medical history, clinical manifestations and other circumstances to make a diagnosis and carry out relevant treatment. Patients should not make their own diagnosis based on imaging reports.