Whether small lymph nodes in the mediastinum is important or not depends on the specific situation, if the patient has no obvious symptoms, it is not important, if the small lymph nodes in the mediastinum are caused by pathological factors such as tuberculosis, inflammation, mediastinal malignant tumors or metastatic carcinoma, it is an important situation, and it should be consulted in time to find out the cause of the disease. Lymph nodes are an integral part of the body’s immune organs. Small lymph nodes are lymph nodes smaller than 10 millimeters, which usually have no pathological significance and do not require special treatment if the patient has no obvious symptoms. If the small lymph nodes in the mediastinum of the lungs are caused by pathological factors, such as tuberculosis, inflammation, mediastinal malignant tumor or metastatic carcinoma, the situation is more critical at this time. 1. Tuberculosis: If there are multiple enlarged lymph nodes with calcification in the mediastinum, it is highly suggestive of tuberculosis infection, and sputum mycobacterium tuberculosis examination should be done in hospital. 2. Inflammation: Most of the mediastinal lymph nodes are caused by inflammation in areas such as pneumonia or chest cavity, which is usually accompanied by high fever. 3. mediastinal malignant tumor or metastatic cancer: mediastinal lymph nodes in the lungs caused by tumors usually do not have any accompanying symptoms, and imaging examination, pathological biopsy, PET-CT examination, etc. are needed to determine the location of the primary cancer as well as the type of tumor. Therefore, small lymph nodes in the mediastinum of the lungs need to be diagnosed and treated promptly by a doctor who integrates the patient’s past history, clinical manifestations, laboratory and other tests.