Pulmonary malignancy can be seen in primary bronchopulmonary carcinoma and also in other extra-pulmonary tumors of pulmonary metastases.CT mainly shows that the lesion is an eccentric cavity and the cavity wall is irregular, which can present spherical or lobulated mass shadow, and there can be different shapes and irregular burr-like shadows with extremely irregular margins and unclear boundaries. When cachexia is accompanied by pleural effusion, there may be a distinct external high and internal low, rounded effusion shadow. In severe cases, localized pulmonary atelectasis and compensatory emphysema may develop, and in combination with other pathogenic infections, the infected lesion may appear as a diffuse, dense shadow of obstructive pneumonia.