Thymoma cannot be diagnosed clinically only by some symptoms of thymoma, such as chest pain and chest tightness, etc. The diagnosis of thymoma needs to be based on the pathological findings of the lesion, and also combined with clinical symptoms and some imaging findings. Thymoma belongs to a kind of mediastinal tumor, the tumor mainly originates from thymic epithelial cells, and the specific etiology is still unclear. Clinical diagnosis of thymoma should be based on the following aspects. 1. Clinical symptoms of thymoma include chest pain and discomfort, chest tightness, shortness of breath, hoarseness, myasthenia gravis, etc. 2. 2. Imaging results are mainly chest CT examination, which can see the thymic mass, or the mass in the anterior mediastinum. 3. Pathologic findings are necessary to confirm the diagnosis of thymoma.