Type AB thymoma is a malignant tumor, but less malignant. According to the proportion of lymphocytes and spindle cells in thymoma, it can be classified as type A thymoma, type AB thymoma, type B thymoma and type C thymoma, and their malignant degree is in increasing order. type C and B3 thymoma have the highest malignant degree, which is also known as thymic carcinoma, while type B thymoma is considered as a juxtapaposition of tumors, and type AB thymoma is a tumor with a relatively low malignant degree. Type B thymoma is considered to be a junctional tumor, while type AB thymoma is a relatively less malignant tumor. If there is any discomfort, it is recommended to go to a regular hospital for examination and treatment.