It mainly depends on the size of the cyst, the presence or absence of internal hemorrhage and infection, as well as the degree of compression or corrosion of adjacent organs (trachea, esophagus, lungs) and the performance of different symptoms. The onset of the disease may be rapid or slow, and usually consult the doctor with the following symptoms: 1. Symptoms (1) obstruction of the airway: compression and narrowing of the trachea may appear as shortness of breath, wheezing, and perioral bruising. If there is infection in the lungs, the lack of oxygen is more obvious, and in severe cases, asphyxiation may occur suddenly. When the cyst is huge, it can lead to mediastinal displacement, cardiac compression, and cardiopulmonary dysfunction can occur at the same time. If the diagnosis and treatment in time, the cyst emergency puncture fluid decompression, the condition can be immediately relieved, in order to fight for the time of surgery, otherwise, it is easy to lead to death. (2) hemoptysis, hematemesis: large cysts often have adhesion with the lungs, acidic cystic fluid corrosion of the cyst wall rupture into the lungs, it will cause destruction of lung tissue, vascular blood seepage and manifested as hemoptysis. There are two sources of blood in stool: ① children will not vomit, blood from the trachea through the pharynx into the intestinal pharynx. ② The internal hemorrhage of luminal esophageal cyst can be discharged directly from the intestine. (3) Dysphagia or vomiting: as the compression of the cyst on the esophagus aggravates, progressive dysphagia or even vomiting may occur. Barium examination can easily confirm the diagnosis. Physical signs: the affected side of the chest is full, the rib space is widened, the main trachea is shifted, the percussion is turbid, and the auscultation can have the whistling sound reduced. When the lung is infected, wet sounds can be heard. Clinical manifestations: dyspnea, cyanosis, hemoptysis, hematemesis, dysphagia, and dysphagia without obvious causes. Physical examination: the affected side of the thorax is full, the rib space is widened, the main trachea is displaced, and a bulging mass can be seen on the side of the neck in the case of a large repetitive deformity occurring in the neck. 4.Assistant examination: suggesting posterior mediastinal mass, compression of esophagus and trachea.