I. Pathogenesis The mediastinum is located between the right and left pleural cavities, with the entrance to the thoracic cavity above, the diaphragm below, the sternum in front, and the thoracic vertebrae behind. The mediastinum is roughly divided into anterior, middle and posterior zones according to its location from front to back. The anterior mediastinum is mainly the thymus, lymph and soft tissues, the middle mediastinum has the heart and large blood vessels, trachea, esophagus, nerves and lymph nodes, etc., and the posterior mediastinum is mainly peripheral nerves. Mediastinal tumors are divided into primary and secondary, benign and malignant, with benign tumors predominating in primary cases. The most common malignant tumors of the anterior mediastinum are lymphoma, thymoma, malignant teratoma, and rhabdomyosarcoma; the most common malignant tumors of the middle mediastinum are lymphoma and soft tissue tumors; and the most common malignant tumors of the posterior mediastinum are tumors of nerve fiber origin. However, sometimes the tumors are so large that it is difficult to distinguish from which region the primary tumor actually comes from. Second, abnormal performance Most mediastinal tumors often do not have obvious self-conscious symptoms, but are occasionally found during routine physical examination of chest radiographs or chest radiographs taken for other reasons. Common symptoms are chest tightness, dyspnea, hoarseness, head and face edema, cough, swallowing discomfort or obstruction. Some thymic tumors can also have small eye fissures (caused by ptosis), general weakness or even lack of strength to breathe, called myasthenia gravis. If it is a posterior mediastinal tumor, it can cause back pain. Neurogenic tumor: it accounts for 30% of mediastinal tumors, ranking first in mediastinal tumors. There is no obvious difference in the incidence rate between men and women, and it can occur at any age. Most patients have no conscious symptoms, and those with symptoms often manifest as: chest and back pain and chest tightness with inexact site, sometimes intercostal neuralgia and sensory abnormality of nerve function area, ganglion cell carcinoma can compress cervical sympathetic ganglion, and Horner’s syndrome can appear. Teratoma: it accounts for the second place of mediastinal tumor, 80% occurs in 20-40 years old, malignant teratoma is more common in male than female. more than 80% of cases have symptoms, which are mainly manifested as: retrosternal stuffiness, chest pain, coughing and shortness of breath, panic, and blood in sputum. Lung sepsis and pus chest can be formed, such as the emergence of bronchial fistula sputum can have hair. Thymoma: It accounts for 20% of mediastinal tumors, ranking the third, mostly located in the anterior mediastinum. It occurs in adults, and is more common in 40-50 years old. Most patients have no conscious symptoms. If the tumor is large and compresses the lungs or bronchial tubes, there are the following manifestations: ① cough, chest pain, locomotor palpitation, shortness of breath. Myasthenia gravis is the specific symptom of this disease. It is manifested as indifferent expression, drooping eyelids, weakness of chewing, dysphagia, dyspnea and so on. ③ malignant thymoma: severe cough, severe dyspnea, superior vena cava compression syndrome, manifested as: edema of neck, upper chest and face, thoracic and dorsal varicose veins, jugular vein rage and pleural effusion. Intrathoracic goiter: mostly formed by cervical goiter or adenoma extending to the back of the sternum, the main symptoms are: ① tracheal compression symptoms: cough, dyspnea. Anterior chest tightness and back pain, as the manifestation of sternal and spinal compression. ② Hyperthyroidism manifested as hyperphagia, emaciation, tachycardia, excessive sweating, impatience and irritability. (iii) Poor feeding or difficulty in swallowing as a result of esophageal compression. ④ Symptoms of superior vena cava compression, neck enlargement or mass, and tracheal displacement. Signs of mediastinal tumor: anterior mediastinal tumor can be seen as sternal bulge, sometimes with pulsation. Mediastinal lymphoma can be a part of systemic lymphoma in the mediastinum or primary in the mediastinum. The former should be handled as systemic lymphoma, including chemotherapy and radiotherapy to the whole lymph nodes; the latter, if it is non-Hodgkin’s lymphoma, should be handled by the treatment of leukemia, with chemotherapy as the main treatment. Importance of radiotherapy for mediastinal soft tissue tumors Mediastinal malignant soft tissue sarcomas include rhabdomyosarcoma, liposarcoma and tumors of neural tissue origin, and tumors of neural tissue origin account for most of them, such as malignant neuroblastoma, neurofibrosarcoma, malignant nerve sheath tumors, which are more common to occur in the posterior mediastinum. Like soft tissue sarcoma of trunk and limbs, malignant soft tissue sarcoma of mediastinum should be surgically resected. Even if the tumor can be completely removed, postoperative prophylactic radiotherapy is still needed to improve the local tumor control rate, reduce recurrence and consolidate the results of surgery. V. Prognosis of mediastinal tumors Lymphatic and hematogenous metastasis of thymoma is rare, and metastasis almost mostly occurs in infiltrative type. Therefore, the infiltrative nature of the tumor is an important factor affecting the prognosis. Non-infiltrating type 100% can be completely resected, the postoperative local recurrence rate is below 3.8%, and the 5-year survival rate is 85%~100%. Infiltrating type 58% can be completely resected, local recurrence rate 20%, 5-year survival rate 33%~55%. VI. Abnormal signals of mediastinal tumor Non-infectious irritating dry cough, chest pain, retrosternal pain, unexplained hoarseness, numbness of upper limbs, edema of head and face should be alerted to this disease, and X-ray examination should be carried out in time; such as coughing up sputum with hair and sebum-like liquid should be paid attention to in particular. Rehabilitation and health care 1, maintain a good mood, optimistic about life. 2. Pay attention to the change of environment and climate, arrange outdoor activities appropriately, and enhance physical fitness. 3.Pay attention to keep in touch with the treated doctor and have regular review. 4.During the recovery period, if recurrence of the disease is found, do not seek medical advice indiscriminately and go to a specialized hospital as soon as possible. 5.Patients with superior vena cava syndrome should pay attention to low-salt diet, adopt head-high-feet-low position when resting, elevate the head at an angle of 15°~30°, and avoid intravenous infusion in the upper limbs. 6.Live a regular life, get up and down on time, quit smoking and drinking, and prevent colds.