Mediastinal multiple lymph nodes refer to the lymph nodes in the mediastinum that become numerous and multifocal, and the size of the lymph nodes is usually <1 cm. There are usually the following cases: 1. Inflammation-induced mediastinal multiple lymph nodes are rare, usually due to pneumonia or inflammation in the thoracic area, resulting in mediastinal multiple lymph nodes, accompanied by high fever and high temperature, which will gradually disappear with antibiotic treatment; 2. Metastatic cancer or mediastinal lymph nodes caused by malignant tumors, which are not accompanied by any symptoms. The lymph nodes in the mediastinum caused by malignant tumors, which are not accompanied by any symptoms, need to undergo imaging examinations to detect the tumor markers and PET-CT examinations to determine the location of the primary cancer and consider whether surgery can be performed; if surgery is not possible, radiotherapy or chemotherapy should be chosen; in some cases, pathology should be taken from the site of the carcinoma in situ for genetic monitoring to consider whether biological therapy, i.e. targeted drug therapy, can be performed.