Congenital pulmonary cysts

　　During the embryonic development period, due to abnormal budding or branching of the trachea and bronchi, the lesions can occur at different sites of the bronchial branches and show different stages of development. Cysts are often multilocular, but can also be unilocular. The cyst wall often has the structure of small bronchial wall, with ciliated columnar epithelium in the inner layer and scattered small pieces of cartilage visible in the outer layer. Smooth muscle bundles and fibrous tissue can be seen within the wall. The inner layer of the cystic lesion structure shows different types of squamous cells, including columnar, cuboidal, and round epithelial cells, indicating different degrees of incomplete development of the bronchial tree branches. Some have mucous-secreting columnar cells, filled with mucus in the lumen.

　　Complications caused by lung cysts include the following situations:

　　1, Lung cysts themselves have no gas exchange function. Large cysts can compress lung tissue, causing obstruction of pulmonary gas exchange. In severe cases, it can even cause increased pulmonary artery pressure, increasing the burden on the heart.

　　2, Long-term repeated infections are prone to adhesions in surrounding tissues, affecting lung function, increasing the difficulty of surgery, and affecting postoperative recovery.

　　3, Hemorrhage and perforation caused by the destruction of the cyst wall of lung cysts can lead to pneumothorax and hemothorax.

　　4, There are reports in the literature that lung cysts may undergo malignant transformation.

　　Small bronchogenic cysts do not present with symptoms in clinical practice and are only discovered during chest X-ray examination or post-mortem examination. Once the cystic lesions communicate with the small bronchi, secondary infection or the formation of tension pneumothorax, hydropneumothorax, or tension pneumothorax can occur, compressing lung tissue, heart, mediastinum, and trachea, leading to symptoms.

　　1, Neonatal period:Tensional bronchogenic cysts, lobar emphysema, and bullae are more common. Clinically, they often present with symptoms of intrathoracic tensional hypertension, such as tachypnea, cyanosis, or respiratory distress, physical examination shows the trachea deviating to the opposite side, percussion on the affected side produces a resonant sound, breathing sounds are reduced or absent, chest X-ray shows cystic lung lesions on the affected side causing atelectasis, mediastinal shift, and may present with mediastinal hernia and ipsilateral lung atelectasis. The condition is critical, and failure to diagnose and treat in a timely manner can lead to death due to respiratory failure.

　　2, Childhood period:The most common is bronchogenic cyst, with clinical manifestations of recurrent pulmonary infection. Patients often seek medical attention due to fever, cough, chest pain, with symptoms similar to bronchopneumonia.

　　3. Adult stage:Commonly seen in secondary pulmonary bullae and bronchogenic cysts acquired later, the clinical manifestations are all due to secondary infection, such as fever, cough, sputum, hemoptysis, chest tightness, asthmatic发作, exertional dyspnea, and recurrent pneumothorax, etc. They need to be differentiated from lung abscess, empyema, bronchiectasis, lung tuberculosis cavity, and pulmonary tumors, etc.

　　Currently, there are no effective preventive measures.

　　Efficacy assessment:

　　1. Cured: Symptoms disappeared after surgery, and the remaining lung expanded well;

　　2. Improved: Symptoms improved after surgery;

　　3. Unhealed: Symptoms have not improved.

　　1. Mainly X-ray examination

　　The clinical symptoms of this disease are atypical, and differential diagnosis should be noted. Chest X-ray examination shows clear edge round or elliptical dense shadows, or round or elliptical thin-walled radiolucent cavity shadows with fluid levels.

　　Congenital bronchogenic cyst: Common in children, the cyst is located in the pulmonary interstitium or mediastinum, about 70% located within the lung, and 30% located in the mediastinum. Since the cyst can be single or multiple, with different amounts of gas or fluid, it can present differently on chest X-rays:

　　1. Single fluid and air cyst:

　　The most common type is a single air cyst with varying sizes, visible as round thin-walled cysts with fluid levels inside. The characteristics of this type of cyst are thin cyst walls, no inflammatory infiltrative lesions in the adjacent lung tissue, and few fibrotic changes. They need to be differentiated from lung abscess, lung tuberculosis cavity, and hydatid cyst of the lung. On X-rays, the wall of the lung abscess is thicker, with obvious surrounding inflammation. The lung tuberculosis cavity has a longer history, with surrounding tuberculosis satellite lesions. The hydatid cyst of the lung has epidemiological regional characteristics, life history, occupational history, blood tests, intradermal tests, etc., which are helpful for differentiation.

　　2. Single air cyst:

　　Chest X-rays show air cysts in the affected lung side. Large air cysts can occupy one side of the pleural cavity, compressing the lung, trachea, mediastinum, and heart. They need to be differentiated from pneumothorax. The characteristic of pneumothorax is the atrophy of the lung pushing towards the hilum, while the air in the air cysts is located within the lung, often visible upon careful observation at the lung apex and costodiaphragmatic angle, where lung tissue can be seen.

　　3. Multiple air cysts:

　　Clinically, it is also common to see multiple air cysts of different sizes and irregular edges on chest X-rays. They need to be differentiated from multiple bullae, especially in children, where bullae often accompany pneumonia. On X-rays, the characteristic features are translucent, thin-walled large bullae with their size, number, and morphological variability. Changes are often seen in short-term follow-up, and sometimes they can increase rapidly or rupture to form pneumothorax. Once the pulmonary inflammation subsides, the bullae can sometimes shrink or disappear spontaneously.

　　4. Multiple fluid and air cysts:

　　On chest X-rays, multiple sizes of fluid and air cavities can be seen, especially when the lesion is located on the left side, which needs to be differentiated from congenital diaphragmatic hernia. The latter can also present as multiple fluid levels. If necessary, oral iodine oil or dilute barium examination is required. If contrast medium is seen entering the gastrointestinal tract within the pleural cavity, it is a diaphragmatic hernia.

　　Two, pulmonary function tests, bronchography, and CT scans are also beneficial for the diagnosis of this disease.

　　Firstly, what should be paid attention to in the diet of pulmonary cysts:

　　1. Diet should be light, eat less fat, high sugar, spicy, fried foods, and alcoholic beverages such as white wine and coffee, and eat more vegetables, fruits, fibrous foods, and drink more water.

　　2. Maintain a pleasant mood, ensure good sleep, strengthen physical exercise, such as jogging, Tai Chi, and so on.

　　Secondly, dietary taboos for pulmonary cysts:

　　Diet should be light, and spicy and刺激性 foods should be avoided.

　　1. Generally, diagnosis should be clear, and early surgery should be performed without acute inflammation. Because cysts are prone to secondary infection, drug treatment cannot only cure the disease but also, due to the inflammatory response around the cyst wall after multiple infections, causes widespread pleural adhesions, making surgery more difficult and prone to complications. Young age is not an absolute contraindication for surgery. Especially in cases with hypoxia, cyanosis, and respiratory distress, early surgery, even emergency surgery, should be performed to save lives.

　　2. The surgical method should be determined according to the location, size, and infection of the lesion: an uninfected cyst isolated under the pleura can be removed by simple cystectomy; a cyst limited to the lung margin can be removed by lung wedge resection; a cyst infected with surrounding adhesions or adjacent bronchial dilation can be removed by lung lobectomy or pneumonectomy. In the case of bilateral lesions, the side with severe lesions can be operated on first under the premise of surgical indications. For children, the principle is to retain as much normal lung tissue as possible.

　　3. When diagnosing the disease clinically, it should be avoided to perform pleural puncture to prevent pleural infection or tension pneumothorax. Only in a few cases, where there are severe signs of respiratory distress, cyanosis, and severe hypoxia, and there is no condition for emergency surgery, can cyst puncture and drainage be performed to achieve temporary decompression, relieve respiratory distress symptoms, and serve as a temporary emergency measure before surgery. Generally, the prognosis is good after the removal of the diseased cyst or lung lobe.

　　4. In adult patients, if there is a large amount of sputum before surgery, double-lumen tracheal intubation anesthesia is required during surgery to prevent sputum from flowing back to the opposite side. Children can adopt a low-lateral prone position with the affected side lower for thoracotomy, and after entering the chest, the bronchus of the diseased lung should be ligated first.

　　5. If the lesion is too extensive, the lung function is severely decreased, or there are serious organic diseases such as heart, liver, and kidney, surgery should be禁忌.