右肺中叶不张是常见的X线征象之一,既往都认为其病因以非特异性炎症和结核为多,肿瘤较少见。但随着肺癌发病率的上升,在肺中叶不张中肺癌的比数已有所增加,加上良、恶性病变的治疗原则截然不同, The right middle lobe is one of the common X-ray signs. It was previously believed that the cause of the disease is non-specific inflammation and tuberculosis, and tumors are rare. However, with the increase in the incidence of lung cancer, the ratio of lung cancer in the middle lobe of atelectasis has increased, plus the treatment principles of benign and malignant lesions are very different.