The soft tissue shadow of anterior superior mediastinum with unclear border may be thymoma, and it is necessary to go to the hospital to do X-ray or CT examination in time to clarify the disease and treat the symptoms. Early stage of thymoma usually has no obvious symptoms, and can only be determined by examination. If the examination shows that the soft tissue shadow of anterior superior mediastinum has unclear boundary, and it is lobulated with non-uniform density, the possibility of thymoma is relatively large, and it needs to be further examined. Thymoma may appear symptoms such as shortness of breath, shortness of breath, hoarseness and so on with the enlargement of the tumor. If metastasis of pleural membrane occurs, symptoms such as chest tightness, shortness of breath, panic may appear, etc. In early stage, it can be treated by surgical resection; in late stage when the cancer spreads and there is no surgical indication, it can only be relieved from symptoms by chemotherapy and radiotherapy to control the spread of cancer cells. Early detection and early treatment can avoid serious condition and irreversible damage to the body.