In the outpatient department of thoracic surgery, patients with pulmonary nodules found in physical examination are often met and asked with nervous mood, is it lung cancer? There are benign and malignant pulmonary nodules, including pulmonary tuberculosis and benign lung tumors (hamartoma, lipoma, etc.). ), lung inflammation (spherical pneumonia, inflammatory pseudotumor), pulmonary cyst, pulmonary sequestration, etc. Malignant nodules include primary malignant tumors (lung cancer, carcinoid tumor) and secondary malignant tumors (metastatic cancer). Wang Jingdi, from the Department of Thoracic Surgery, Peking University Third Hospital, first asked if there were any discomfort symptoms in the near future, such as cough, expectoration, hemoptysis, chest pain, dyspnea, fever, emaciation and hoarseness. Secondly, review the past medical history, especially whether you have other types of malignant tumors. If you have a chest X-ray or chest CT before, find out and compare it with the film of this examination to see if the nodule is recent or before. Pathological diagnosis is the final basis for judging the nature of pulmonary nodules. If the patient has sputum, check whether there are tumor cells and tuberculosis in the sputum. If there is pleural effusion, puncture and extract the effusion for cytological examination. Fiberoptic bronchoscopy biopsy is suitable for central lesions near airway, and CT-guided puncture is suitable for peripheral lesions near chest wall. Cytological examination and biopsy, due to the limitation of the number and location of samples, may also have negative results for real tumor lesions. At this time, other means can be taken, such as blood tumor markers (SCC- squamous cell carcinoma, CEA- adenocarcinoma, NSE- small cell carcinoma), isotope tumor-friendly imaging, PET-CT, tuberculin skin test (PPD), ESR, blood tuberculosis antibody, etc., to indirectly provide diagnostic reference. The past history of tumors in other parts of the body is of great significance to the diagnosis of lung metastases. If the nature of the lesion cannot be determined after the above examination, two different treatment methods can be adopted according to the patient's wishes. The first is observation, and the imaging examination is reviewed regularly. The initial interval is 3-6 months. If the lesion remains stable, it can be extended to 6- 12 months. After long-term observation, if the focus tends to increase during the observation period, unless the patient's body can't stand it, surgery should be taken. If the possibility of inflammation is considered, give 1-2 weeks of anti-infection treatment for re-examination. It is suitable for patients who cannot tolerate surgery or have fears and doubts about surgery. The second is surgical exploration. Through thoracoscopy or small incision thoracotomy, rapid pathological examination was performed when the lesion was locally removed. If it is benign, the operation is over. If it is malignant, expand the scope of resection and perform radical surgery. Suitable for patients who can tolerate surgery and are willing to operate. Before the operation, patients need to be evaluated in two aspects: one is the cardiopulmonary function to judge the patient's tolerance to the operation, and the other is the clinical stage of the tumor, except for the possible distant metastasis. Patients with metastasis are not suitable for radical surgery.