The diagnosis of malignant tumors is based on x-ray examination, and most of them are found incidentally during routine x-ray examinations, which may show uniform and dense shadows or heterogeneous shadows, as well as calcifications, which may appear as popcorn-like patterns with relatively low periphery and may be fatty tissue. The popcorn sign is a characteristic feature of pulmonary malformation tumors, but is rare and not unique to pulmonary malformation tumors. Pulmonary malformation tumors are usually solitary, but multiple cases are extremely rare and have not been reported in China. The majority of solitary malformations are intra-pulmonary parenchymal and the intra-bronchial type is rare. They are more frequent in the right lung than in the left lung, and more frequent in the lower lobe than in the upper lobe, with some occurring in the right middle lobe and in the lingual segment of the left upper lobe. Pulmonary malformations found on healthy physical examination are sometimes extremely difficult to distinguish from intrapulmonary malignancies due to the lack of dynamic observation, and those that increase rapidly in size in a short period of time are also difficult to diagnose. Therefore, surgery should be performed as soon as possible when malignancy cannot be ruled out clinically and radiographically. Even for benign malignant tumors, early surgery can avoid pneumonia, atelectasis, bronchiectasis and other complications caused by the enlargement of the tumor, which may aggravate or complicate the disease. The surgery is performed under general anesthesia. After opening the chest, the tumor can be seen on the surface of the lung, with hard texture and unsmooth surface, and the tumor can be felt sliding in the lung tissue. The tumor can be completely removed by slightly separating the lung tissue. Except for endobronchial malignant tumors or those that cannot be ruled out as malignant, local resection or lung segmental resection is usually performed. The origin and cause of pulmonary malformation is not well understood. The more acceptable hypothesis is that malformation is a piece of bronchial tissue that is inverted and detached during embryonic development and is surrounded by normal lung tissue, which grows slowly or may not grow for a certain period of time and then gradually develops to form a tumor. This hypothesis is supported by the fact that the majority of malformations develop after the age of 40. The pathology of malformations is characterized by abnormal combinations and arrangements of normal tissues, and this histologic abnormality may be a mismatch in the number, structure, or maturation of organ tissues. The major tissue components of a malformation tumor include cartilage, fat, smooth muscle, glands, epithelial cells, and sometimes bone tissue or calcifications. Malignant transformation of malformations has not been reported. Malformations are usually spherical or ovoid with dense parenchyma, but can also be lobulated or nodular, with most being 3 cm in diameter. Clinical manifestations The age of onset of misshapen tumors is mostly above 40 years old, and more men than women. Most of the misshapen tumors (more than 80%) grow in the peripheral part of the lung, immediately under the dirty pleura of the lung, sometimes protruding from the surface of the lung, so there are usually no clinical symptoms and no positive signs on examination. Only when the misshapen tumor grows to a certain size, which is enough to irritate the bronchi or compress the bronchi causing bronchial narrowing or obstruction, clinical symptoms such as cough, chest pain, fever, shortness of breath, bloody sputum and even hemoptysis will appear.