There is no definite clinical conclusion on how long it takes for thymoma to progress from onset to progression. Thymoma is a mediastinal tumor that occurs in middle-aged and elderly people between 50 and 60 years old. In the early stage of thymoma, 50%-60% of patients have no symptoms and are only found by chance during physical examination. 25% of patients have tumor invasion or compression of adjacent mediastinal structures, causing cough, chest pain, dyspnea, dysphagia and recurrent respiratory infections. If patients develop hoarseness, pleural fluid, causing dyspnea, chest pain, chest discomfort, or even distant metastases such as severe muscle weakness and bones, it usually indicates malignant and spreading disease, but there is no clear time period for the process, which is mainly related to the progress of the disease in individual patients. After discovering thymic tumor, patients should promptly go to the thoracic surgery department for timely treatment after perfecting relevant examinations, which can prevent the occurrence of deterioration to a certain extent.