I. General overview Primary benign tumors and aneurysmal lesions of the lung are relatively rare, while there are many types of tumors, accounting for about 5% of bronchial and pulmonary neoplasms. About 94% are in the lungs and 6% grow in the bronchi. Most of them appear as single small nodules; the majority of benign lung and bronchial tumors are peripheral type tumors. Most benign lung and bronchial tumors are peripheral tumors. They are usually without clinical symptoms and are only detected during chest X-ray. A few benign tumors located in larger bronchi may show symptoms of cough, fever and bronchial obstruction, but rarely hemoptysis. Common types: 1. Common tumors of trachea and main bronchus. These include: papilloma, polyp, granuloma, lipoma, fibroma, other tracheal tumors (hemangioma, lymphadenoma, fibrocystic osteitis, etc.); 2. Tumors that develop in the trachea, main bronchus, distal bronchus, lung, etc. These include: smooth muscle tumors, neurogenic tumors, etc.; 3. Common tumors of the distal bronchi and lungs. These include: malformation tumor, pulmonary arteriovenous fistula, inflammatory pseudotumor, sclerosing hemangioma, thymoma and teratoma, etc. Most of the common causes and pathogenesis are unknown. Some tumors originate from epithelial and mesenchymal tissues. Some tumors are associated with bacterial or viral infections of the respiratory system. Some of them are familial in origin. A small number of diseases are formed by congenital developmental abnormalities. Clinical characteristics 1. depends on the size and location of the tumor. Most of the small nodules in the peripheral lung parenchyma are asymptomatic and are only found after chest radiographs, accounting for 60%. 2. Tumors located in large bronchial cavities may present with bronchial obstruction, pulmonary atelectasis and pneumonia, cough, chest pain, croup and occasional hemoptysis (<3%). The diagnosis of this disease is difficult to make a definite diagnosis before surgery. Chest X-ray can mostly detect and initially determine benign lesions, but cannot confirm the diagnosis. For masses close to the chest wall, percutaneous lung aspiration biopsy can help to make the diagnosis. Although benign bronchial and pulmonary tumors and tumor-like lesions are benign diseases, they are not easily distinguished from early malignant tumors of the lung. The latter are more frequent; benign lesions may be malignant; benign lesions may be accompanied by malignant lesions (28% of pulmonary malignancies are accompanied by primary malignant tumors). Differentiation from lung cancer: imaging data of peripheral type lung cancer often suggest lobulated and burr signs in the mass and indentation of the dirty pleura due to tumor traction. Patients with central type lung cancer often have symptoms such as irritating cough and hemoptysis, and imaging data often suggest a hilar mass with pulmonary atelectasis or obstructive pneumonia. Patients often seek medical attention for hemoptysis or irritating dry cough. In general, benign lesions can be cured by simple excision, and conservative excision is generally used. Nowadays, some scholars advocate conservative observation of pulmonary malformation tumors, but observation must be considered only when biopsy results are obtained. The principles of surgery are as follows: 1. Peripheral lesions: limited resection by thoracotomy, including pulmonary wedge resection or mass enucleation; surgical resection by thoracoscopy is also available. 2, central lesions: benign lesions growing in the large bronchi, can be treated by bronchoscopic resection or laser. 3, when there is destruction of lung tissue, or when there is obstruction causing bronchial expansion or lung abscess, a more radical resection should be made, including lobectomy or even total lung resection. The effect of surgical treatment is clear, but if the resection is not clean, there is a tendency of recurrence.