患者男性，20岁。因左胸痛、干咳、气促一个月入院。体检：左上胸廓略隆起，气管右偏，左上肺叩诊为实音，无紫绀及杵状指，听诊左上肺前胸区呼吸音减弱，背部呼吸音增强，未闻及干湿性罗音。心界无扩大，心律正常，无杂音。X线胸片诊断：纵隔类圆形占位病变，边缘清楚，密度均 The patient is male, 20 years old. Left chest pain, dry cough, shortness of breath admitted to hospital one month. Physical examination: slightly elevated upper left chest, right trachea deviation, left upper lung percussion as real sound, no purpura and clubbing, auscultation of breath sounds in the chest area of ​​the upper left lung weakened, back breath sounds enhanced, and dry and wet rales were not heard. There is no expansion of the heart, heart rate is normal, no noise. Diagnosis of X-ray: Mediastinal round lesions with clear edges and density