Pulmonary sarcoma (PPS) is a rare malignant tumor of the lung, the incidence of which is reported at home and abroad to account for only 6% of primary malignant tumors of the lung. 12 cases were admitted from June 2002 to July 2007, and are reported below. 1. Data and methods 1.1 General data Among the 12 cases in this group, 10 were male and 2 were female; their ages ranged from 5 to 57 years old, with an average of 36 years old. 4 cases (33.3%) were under 30 years old. The main clinical manifestations were cough (10/12, 83.3%), chest pain (4/12, 33.3%), hoarseness (2/12, 16.6%), etc. One case had no self-conscious symptoms. 1.2 Preoperative examination All patients showed clear boundary and large round-like or irregular mass in the lung in preoperative chest X-ray and chest CT examination. 11 patients had tumor diameter between 5 and 10 cm, and one case showed huge mass in the chest cavity, which occupied the whole chest cavity. The tumor was located in the left lung in 5 cases, including 4 cases in the upper lobe of the left lung and 1 case in the left whole lung; in the right lung in 7 cases, including 6 cases in the upper lobe of the right lung and 1 case in the middle lobe of the right lung. Preoperative fiberoptic bronchoscopy did not reveal any neoplasm in the bronchial lumen in any of the 12 patients, while external pressure stenosis of the bronchus was found in 11 cases and no abnormal findings in 1 case. 9 patients were misdiagnosed as primary lung cancer and 3 cases were misdiagnosed as congenital pulmonary cyst. 1.3 Treatment All 12 patients were treated surgically, including surgical resection of the upper lobe of the right lung in 6 cases, the middle lobe of the right lung in 1 case, the upper lobe of the left lung in 4 cases, and the left whole lung in 1 case, and the surgery went smoothly with no surgical death or postoperative complications. 2, results Postoperative pathological diagnosis of smooth muscle sarcoma in 8 cases, fibrosarcoma in 2 cases, rhabdomyosarcoma in 2 cases; tumors are all intrapulmonary parenchymal infiltration type, the mass section is mostly gray-white fishy, with clear boundaries with the surrounding lung tissue and the presence of fiber envelope. Intraoperatively, 8 patients were found to have mural pleural invasion, 1 case had mediastinal lymph node metastasis in the hilum, and 3 cases had no obvious invasion or lymph node metastasis. Postoperatively, radiotherapy and chemotherapy were administered to 12 patients. The postoperative survival was 18, 19, 21, 25, 27, 29, 31, and 33 months for 8 patients with smooth muscle sarcoma, 21 and 24 months for 2 cases of fibrosarcoma, and 28 and 31 months for 2 cases of rhabdomyosarcoma. The cause of death was tumor recurrence or metastasis in all cases. Primary pulmonary sarcoma is a rare malignant tumor of the lung, the incidence of which accounts for only 0.6% of the primary malignant tumors of the lung reported at home and abroad, and originates from mesenchymal tissue such as lung mesenchyme, bronchial wall, blood vessel wall, bronchial cartilage, etc. Among them, smooth muscle sarcoma is the most common, followed by fibrosarcoma, malignant fibrous histiocytoma and so on. The pathological types are smooth muscle sarcoma, mesothelial sarcoma, fibrous tissue sarcoma, liposarcoma, rhabdomyosarcoma, etc. The symptoms and signs and X-ray examination of primary pulmonary sarcoma are not specific, and the clinical manifestations are similar to those of bronchopulmonary carcinoma. Symptoms such as cough, hematochezia and chest pain are difficult to distinguish from lung cancer, and some of them are asymptomatic, which makes preoperative diagnosis more difficult. In this group of patients, no one was diagnosed at the time of admission, 9 patients were misdiagnosed as primary lung cancer, and 3 were misdiagnosed as congenital pulmonary cysts. Percutaneous lung puncture can be helpful in the diagnosis of pulmonary sarcoma, but the positive rate of puncture biopsy is low because of the small amount of material taken and the close tissue. In recent years, with the development of television thoracoscopic technology, some people advocate television thoracoscopic lung biopsy, which has some diagnostic value for pulmonary sarcoma. The age of onset of primary pulmonary sarcoma is younger than that of primary bronchopulmonary carcinoma, and the average age of this group was only 36 years old. All patients in this group had clear borders and large round-like or irregular mass shadows in the lung on preoperative X-ray chest film or chest CT, and the masses of pulmonary sarcoma were mostly larger, among which 11 patients had tumor diameters of 5-10 cm, and one case showed a huge mass shadow in the chest. In contrast, usually, bronchopulmonary carcinoma is mostly its infiltrative growth, and imaging often has unsmooth margins and the presence of burrs, mostly with the presence of pulmonary atelectasis or obstructive pneumonia. Some authors believe that for solid masses of 10 cm or more in the lung, uniform and dense, with clear contours and smooth margins, pulmonary sarcoma should be considered regardless of the presence or absence of lobes, and this view has some significance for the differentiation between lung cancer and pulmonary sarcoma. The treatment of lung sarcoma is surgical resection as the preferred treatment. Because primary pulmonary sarcoma has expansive growth, relatively slow growth rate, clear demarcation with surrounding tissues and no regional lymph node metastasis, surgical resection is preferred for its treatment. Lobectomy is generally used, but it should be done according to the location, size and invasion of the tumor in order to achieve the goal of radical resection. The prognosis of primary pulmonary sarcoma is mainly related to the size of the tumor, the degree of invasion, surgical resection or not, and the type of sarcoma pathology. Postoperative 5-year survival rates ranging from 0 to 50% have been reported, and the postoperative prognosis is better than that of bronchopulmonary carcinoma. In our group, the overall 5-year survival rate was 0, but most of them survived for more than 2 years. If the tumor is detected early and the lesion is limited, surgical resection still has the possibility of long-term survival. Therefore, once a lung tumor is diagnosed as sarcoma, as long as there is no distant metastasis or invasion of important organs, even if the tumor is large, surgical resection should be actively considered.