The new WHO classification of thymic adenoma has never been published, which makes the recognition and judgment of thymic adenoma by thoracic surgeons less precise than that of lung and esophageal cancer. The 2004 edition of the WHO classification divides thymic epithelial tumors into A, AB, B1, B2, and B3 (and a few other types) types of thymoma and thymic carcinoma. The older Masaoka clinical staging (developed in 1978 and revised in 1981) is divided into 4 stages. The two are different, the former being formulated according to cell type and the latter according to clinical tumor biological behavior, and it is clearly unreasonable to classify them as completely equal. The new classification criteria and reporting methods proposed in the “ITMIG Consensus on WHO Pathological Classification of Thymoma and Thymic Carcinoma” published in the JTO Journal in May 2014 —— meeting can help distinguish various subtypes of thymoma and thymic carcinoma more finely, provide physicians with more basis for differentiation, and help physicians It is hoped that physicians and patients will recognize that It is hoped that physicians and patients will realize that: 1) thymoma is not a traditional “benign” tumor, and even type A has recurrent metastases; 2) the concept of atypical type A thymoma suggests that clinicians should pay attention to the follow-up of all patients including type A thymoma. For thymus occupancy, unless the tumor is clearly a thymic cyst (except cystic teratoma), small, slow-growing and without pressure on adjacent organs, and if there is a fear of surgery, follow-up can be considered, otherwise, solid tumors or solid tumors should be actively removed surgically to clarify the pathological type to prevent the progression of the lesion (especially thymic carcinoma or poorly typed thymoma) and delay the treatment.