Pulmonary inflammatory pseudotumor is a non-neoplastic lesion of unknown etiology that often forms a mass in the lung. It is composed of a variety of inflammatory cells and mesenchymal tissue, including plasma cells, lymphocytes, histiocytes, mast cells, and spindle-type mesenchymal cells. The number of these different types of cells varies from lesion to lesion and even in different areas of the same lesion. Clinically, inflammatory pseudotumors of the lung are uncommon and can occur in both men and women, with patients ranging in age from 1 to 70 years, but are more common in young people, mostly in their 30s. Today half of the patients are asymptomatic, the rest may have symptoms related to the lungs and chest, such as cough, hemoptysis, shortness of breath and chest pain. Some of them may have fever. The lesions can occur in any lobe of the lung and often appear as isolated, well-defined round or ovoid masses on X-ray. In larger cases, the mass is poorly defined, and calcification or cavity formation is occasionally seen. Pulmonary inflammatory pseudotumors are difficult to differentiate from lung cancer, tuberculoma, and malignant tumors, which can make treatment difficult. In clinical practice, the most important thing is to differentiate it from lung cancer, which is directly related to the treatment method and the scope of surgical resection. From the medical history, patients with inflammatory pseudotumors are generally younger, without a long history of smoking, without significant changes in their general condition, and may have a history of transient fever and no persistent blood in the sputum. Since it is difficult to diagnose pneumonic pseudotumor with certainty before surgery, especially difficult to distinguish it from lung cancer, and it may occasionally become cancerous, early surgery is generally recommended. Preliminary judgments can be made during surgery based on what is seen during the exploration, and if necessary, pathological frozen sections can be sent for examination to clarify the diagnosis. After determining the benign nature, surgery is performed to preserve as much normal lung tissue as possible. Inflammatory pseudotumors that are on the surface of the lung are not difficult to eliminate. For inflammatory pseudotumors located in the lung parenchyma, local wedge resection or lung segmental resection should be performed, except for huge masses and those that have invaded the bronchi, lobectomy and total lung resection are usually not performed. The prognosis for surgery is good.