Multiple lymph nodes of different sizes in the mediastinum, hilar region and supraclavicular fossa belong to the description of the condition of lymph nodes in CT examination, and the causes of the corresponding condition mainly include metastatic tumor, immune system disease and inflammatory reaction. 1. Metastatic tumor: the occurrence of multiple tumor metastases will cause corresponding changes, which is a kind of condition after the malignant lesion cells are transferred to lymph nodes. For example, primary bronchial lung cancer is often prone to lymph node metastasis, especially hilar lymph node metastasis. 2. Immune system diseases: immune system related diseases can also lead to corresponding conditions, such as rheumatoid arthritis, systemic lupus erythematosus and so on. 3. Inflammatory reactions: obvious infections in the body will also be associated with the emergence of the condition, and will gradually shrink after the inflammation subsides. Mediastinal and hilar area, supraclavicular fossa multiple lymph nodes of different sizes can also be seen in other diseases, it is recommended that the patient seek medical attention in time, so as to avoid delaying the condition.