Mediastinal tumors are divided into primary mediastinal tumors and secondary mediastinal tumors. The cause of primary mediastinal tumors is unclear and may be due to embryonic development as well as tissue ectasia. Secondary mediastinal tumors are mainly secondary to lung cancer or tumors in other areas. Mediastinal tumors are a collective term for several tumors within the mediastinum, which is located just to the left of the center of the chest cavity. There are various types of mediastinal tumors, mainly divided into primary mediastinal tumors and secondary mediastinal tumors. Currently, there is no authoritative clinical information on the causes of primary mediastinal tumors, and most of them are believed to be related to embryonic development, which is caused by residual germs left in the mediastinum during embryonic development, or may be caused by ectopic planting of tissues outside of the mediastinum into the mediastinum. Secondary mediastinal tumors are mostly considered to be related to lung cancer, mainly secondary to lung cancer, esophageal cancer, breast cancer and abdominal tumors and other tumors in various parts of the body. The causes of mediastinal tumor mainly include congenital factors and tumors in other parts of the body, etc. Patients should go to the hospital in time to find out the causes of the disease and take treatment under the guidance of doctors.