Mediastinal cysts and tumors
Introduction
Introduction of mediastinal cysts and tumors The mediastinum is also the most common site of intracranial tumors in children. The mediastinum is up to the first rib, and the transverse sac is placed. There is a sternum in front, a vertebral body in the back, and a mediastinal pleura around. Its content can have two major groups: 1 heart, large blood vessels, esophagus, trachea and its main branch; 2 thymus and mediastinal lymphoid tissue. basic knowledge Sickness ratio: 0.0001% Susceptible people: no specific population Mode of infection: non-infectious Complications: difficulty swallowing
Cause
Mediastinal cyst and tumor etiology
(1) Causes of the disease
Most occurred in the anterior mediastinum, surrounded by cellulite, but there are also a few tumors closely adhering to the pericardium and large blood vessels. Among the 119 mediastinal tumors and tumors admitted to Beijing Children's Hospital, there are 28 teratomas, accounting for 23.5%; 28 cases Only one case contained extremely poorly differentiated tissues and was diagnosed as malignant teratoma. The other 27 cases were mostly cystic, while the tissues of the outer blast were predominant. The tumor grows slowly, can reach a large volume, and has no self-conscious symptoms before it causes symptoms of compression. It can be complicated by infection, hemorrhage and malignant transformation, and has the potential danger of adhesion and rupture into the trachea and bronchus, and teratoma. The X-ray film may have bones and shadows of the teeth.
Before, the mediastinum is a predilection site for non-Hodgkin's lymphoma. It has high malignancy and rapid growth. It often infiltrates the pleura to cause bloody exudate. The pleural exudate contains malignant tumor cells, which can gradually appear compression symptoms, such as dry cough. Difficulty breathing, etc., can also be malignant quickly within a few days.
Thymoma (thymoma) is rare in children, only occasionally with myasthenia gravis, normal thymus hypertrophy in infants 4 to 15 months, but does not cause symptoms of compression of the trachea and obstruction of the respiratory tract, so there is no need for radiation therapy, with the child As the age increases, it can spontaneously degenerate.
Lymphangioma and hemangioma can also be seen in the mediastinum of the child. Among the 119 cases, there are 14 cases of lymphangioma, and the tumor from the neck continues to enter the anterior superior mediastinum. There is a 5-month-old boy in this group with neck and mediastinum. Lymphangioma, due to severe pressure on the respiratory tract, after emergency tumor decompression, improve the general condition, remove the tumor.
Most of the intrathoracic thyroid tumors are part of the cervical thyroid tumor that protrudes into the mediastinum. Sometimes the thyroid tumor is located in the anterior superior mediastinum, even in the posterior mediastinum.
During embryonic development, for example, some cells in the foregut are ectopic, that is, cysts are formed. The inner membrane of the cyst is ciliated columnar epithelial cells, similar to the bronchial mucosa, called bronchial cysts, as similar to the esophagus and gastrointestinal mucosa. Digestive tract cysts, 5 of the above 119 cases of bronchogenic cysts, located behind the bronchial bifurcation, in front of the esophagus, sometimes deformed with breathing, digestive tract cysts are also considered to be important malformations of the digestive tract, mostly located in the right posterior mediastinum and esophagus Sticking, if the covered gastric mucosa has ulcers and inflammation changes, it may also break into the trachea and bronchi.
Mostly located in the posterior mediastinum, common neuroblastoma, neurofibromatosis, ganglioneuroma and pheochromocytoma, while neuroblastoma and neurofibroma can form a dumbbell shape, part of the ridge groove, by the vertebra The interstitial holes extend into the spinal canal.
(two) pathogenesis
1. The physiology of the mediastinum: The shape of the mediastinum varies from person to person. The percentage of the mediastinal volume of the newborn is higher than that of the adult. The elongated and long mediastinum of the adult is slender, the length of the mediastinum is short and the mediastinum can change with the breathing movement. The mediastinum is elongated when standing and inhaling, and the mediastinum is shortened when lying and exhaling.
When the mediastinum is normal, it is negative pressure. The pressure is 588 kPa (60 mmH2O) when it is affected by bilateral chest pressure. It is beneficial to venous return, especially to promote vena cava blood return to the atria.
There is a large gap between the mediastinal organs, and there is loose tissue inside. Therefore, when there is inflammation, it is easy to spread. When the mediastinum is traumatic, it is easy to accumulate blood, and the gas is compressed and the mediastinum is compressed. When the pressure on one side of the chest is increased, the mediastinum can be caused by inhalation. Displacement, if the intrapleural pressure of the open pneumothorax is decreased, and the mediastinum is easy to the affected side during exhalation, the mediastinal swing can be formed.
2. Classification of pathological conditions: Zeng Yigan summary The mediastinum can be divided into 3 categories under pathological conditions:
(1) Move to the healthy side: due to the large pressure on the affected side, such as a large amount of fluid in one side of the chest, blood pneumothorax.
(2) Move to the affected side: one side of the atelectasis, total lung resection, one side of the lung dysplasia, the trachea, the heart moved to the affected side.
(3) pathological non-displacement: due to the balanced pressure of bilateral lesions, or multiple lesions on one side, the bilateral pressures cancel each other out, the mediastinum does not shift, as the lung dysplasia caused by lateral lung cancer coexists, the mediastinum does not Displacement, in addition to the huge mass in the lung and the fixation of the mediastinum can also form the mediastinum without displacement or displacement.
Prevention
Mediastinal cyst and tumor prevention
Refer to the general tumor prevention methods, understand the risk factors of tumors, and formulate corresponding prevention and treatment strategies to reduce the risk of tumors. There are two basic clues to prevent tumors. Even if tumors have begun to form in the body, they can help the body to improve resistance. These strategies are as follows:
1. Avoid harmful substances (promoting factors): It can help us avoid or minimize exposure to harmful substances.
Some related factors of tumorigenesis are prevented before the onset, and many cancers can be prevented before they are formed. A report in the United States in 1988 compared the international malignant tumors in detail and proposed many external factors of known malignant tumors. In principle, it can be prevented, that is, about 80% of malignant tumors can be prevented by simple lifestyle changes, and traced back. In 1969, Dr. Higginson's research concluded that 90% of malignant tumors are caused by environmental factors," "Environmental factors", "lifestyle" refers to the air we breathe, the water we drink, the food we choose to make, the habits of activities, and social relationships.
2. Improve the body's immunity against tumors: can help to strengthen and strengthen the body's immune system and cancer.
The focus of our current cancer prevention efforts should first focus on and improve those factors that are closely related to our lives, such as quitting smoking, eating properly, exercising regularly, and losing weight. Anyone who follows these simple and reasonable lifestyles can Reduce the chance of cancer.
Promote the body's immunity against cancer: The most important thing to improve the function of the immune system is: diet, exercise and control troubles, healthy lifestyle choices can help us stay away from cancer, maintain good emotional state and appropriate physical exercise can make the body The immune system is at its best, and it is also good for preventing tumors and preventing other diseases. In addition, studies have shown that appropriate activities not only enhance the body's immune system, but also reduce the incidence of colon cancer by increasing the peristalsis of the human intestinal system. Here we mainly understand some of the problems of diet in preventing tumors.
Human epidemiology and animal studies have shown that vitamin A plays an important role in reducing the risk of cancer. Vitamin A supports normal mucosa and vision. It directly or indirectly participates in most of the body's tissue functions. Vitamin A is present in animal tissues. In the liver, whole eggs and whole milk, the plant is in the form of -carotene and carotenoids, which can be converted into vitamin A in the human body. Excessive intake of vitamin A can cause adverse reactions in the body and -carrot This is not the case with carotenoids, and the low vitamin A content in the blood increases the risk of malignant tumors. Studies have shown that those with low levels of vitamin A intake in the blood increase the likelihood of lung cancer, while those with low blood levels in smokers Levels of vitamin A ingestors have the potential to double lung cancer. Vitamin A and its mixture can help remove free radicals in the body (free radicals can cause damage to genetic material), and secondly stimulate the immune system and help differentiate cells in the body. Ordered tissue (while the tumor is characterized by disorder), some theories suggest that vitamin A can help early carcinogens Invasion mutated cells become reversed the occurrence of the normal growth of cells.
In addition, some studies suggest that supplementation with -carotene alone does not reduce the risk of cancer, but rather increases the incidence of lung cancer. However, when -carotene binds to vitamin C, E and other antitoxin substances, its protective effect. It is shown, because it can increase free radicals in the body when it is consumed by itself. In addition, there are interactions between different vitamins. Both human and mouse studies have shown that the use of -carotene can reduce 40% of vitamins in the body. At E-level, a safer strategy is to eat different foods to maintain a balanced vitamin to protect against cancer, as some protective factors have not been discovered so far.
Vitamin C, E is another anti-tumor substance that prevents the harm of carcinogens such as nitrosamines in food. Vitamin C protects sperm from genetic damage and reduces the risk of leukemia, kidney cancer and brain tumors in their offspring. Vitamin E can reduce the risk of skin cancer. Vitamin E has the same anti-tumor effect as vitamin C. It is a scavenger that protects against toxins and scavenges free radicals. The combination of vitamins A, C and E protects the body against toxins. Better than applying it alone.
At present, research on phytochemistry has attracted widespread attention. Phytochemistry is a chemical found in plants, including vitamins and other substances found in plants. Thousands of plant chemicals have been found, many of which have anticancer properties. The protective mechanism of these chemicals not only reduces the activity of carcinogens but also enhances the body's immunity against carcinogens. Most plants provide antioxidant activity that exceeds the protective effects of vitamins A, C, and E, such as a cup of cabbage. Contains 50mg of vitamin C and 13U of vitamin E, but its antioxidant activity is equivalent to the antioxidant activity of 800mg of vitamin C and 1100u of vitamin E. It can be inferred that the antioxidant effect in fruits and vegetables is far better than what we know. The effect of vitamins is strong, and no doubt natural plant products will help prevent cancer in the future.
Complication
Mediastinal cyst and tumor complications Complications, difficulty swallowing
Can be complicated by infection, can cause jugular vein engorgement, can cause difficulty in swallowing, hoarseness and so on.
Symptom
Mediastinal cysts and tumor symptoms Common symptoms Mediastinal lesions Low heat bone destruction Hair dyspnea Difficult pain Painful jugular vein
When the mediastinal tumor or cyst grows to a certain volume, the symptoms of compression appear, or due to concurrent infection, rupture into the trachea, bronchial symptoms.
The most common symptoms are cough, difficulty breathing and cyanosis. Hemoptysis is not common. Tumors in the upper mediastinum may compress the superior vena cava, causing jugular vein engorgement and edema of the face, neck and upper chest. If the esophagus is compressed, it will swallow. Difficulties, when the tumor is oppressed or invaded the vagus nerve, there is hoarseness. Compression of the sympathetic nerve may have Horner syndrome. If there is severe pain, it is often a sign of tumor invasion of the nerve or bone. When the tumor is large, the percussion has local dullness, sometimes The mass was found to extend from the mediastinum to the neck or chest wall.
Radiographic examination: including posterior anterior, lateral or oblique photos, posterior mediastinal tumors can be used for esophageal barium meal imaging, sometimes for tomography.
Examine
Examination of mediastinal cysts and tumors
Mediastinal tumor test is not helpful, and some special cases have reference significance. The diagnosis mainly depends on auxiliary examination.
1. Pheochromocytoma: catecholamines in pheochromocytoma and a small number of neurogenic tumors, high vanillic acid, and vanillyl mandelic acid were measured.
2. Teratoma carcinoid: there may be carcinoembryonic antigen (CEA), alpha fetoprotein (AFP) serum content can be high.
3. Germ cell cancer: Some of the germ cell cancers have some elevated levels of chorionic gonadotropin.
4. Pure red blood cell aplastic anemia with thymoma: pure red blood cell aplastic anemia with thymoma is 1/3 to 1/2, red blood cell system hematopoietic disorder can be seen in bone marrow examination, serum can also be detected, gamma globulin is low (low gamma globulin) disease).
5. Peripheral blood examination: Peripheral blood leukocyte count and neutrophils were significantly increased in concurrent infection, and hemoglobin and red blood cell count decreased, indicating anemia.
X-ray examinations help to diagnose and understand the extent of the lesion and help with treatment.
1. X-ray fluoroscopy and chest lateral radiograph: the main diagnostic method for mediastinal tumor. The fluoroscopy can rotate the position at will. Observe the shape, size and relationship between the tumor and the surrounding area from various aspects, and observe whether the tumor has pulsation or not. Swallowing up and down shifting, can change shape with body position and deep breathing movement, disadvantages: perspective can not save records, clarity, contrast is not as clear as chest.
At least the chest radiograph should be photographed on the lateral side of the chest. The chest radiograph can show the location, shape, size, density and calcification of the tumor. If necessary, take the oblique position of the chest to understand the relationship with the aorta. High-voltage X-ray The slice can be used to understand the relationship between the mediastinum and adjacent structures (the trachea and the main bronchus).
The combination of fluoroscopy and chest radiographs, most mediastinal tumors and cysts can be initially diagnosed. At present, some medical institutions often eliminate the perspective method, which is a big defect. With the appearance of X-ray machine TV surveillance, the perspective should still be maintained. In particular, the extra-thoracic physician should personally inspect the lesion before surgery.
2. Fault (body layer) film: It can show the structure of the tumor layer and its relationship with surrounding organs or tissues. It can still determine whether there is space and micro-calcification in the lesion to make up for the deficiency of flat film.
3. CT scan: CT examination is one of the non-invasive examination methods. It is very helpful for mediastinal lesions. It can be widely used. It can display the internal anatomy and lesions of the mediastinum, and can measure the density of the tumor, help determine the nature of the tumor, and distinguish the body fluid in the mass. , fat, calcified plaque, etc. (CT average, help to determine cystic and parenchyma), CT can also identify vasodilation, distortion or aneurysm, when the thymic tumor is negative, CT is easier to show, in the hilar area Large lymph nodes and solid masses can be distinguished from dilated pulmonary arteries, and CT can still show that changes in tissue space help with the possibility of surgical resection.
4. Magnetic resonance imaging (MRI): MRI is clearer than CT in the mediastinum, and no contrast agent is needed for larger vessels. Therefore, it is easier to separate the blood vessels from the tumor and lymph nodes. The mediastinal lymphatic display is better than CT. MRI application It is currently more valued with chest examinations.
5. Sonic photography: It can show the presence or absence of pulsation and pulsation of the tumor. It can help the identification of aortic aneurysm and mediastinal tumor in the diagnosis of mediastinum. The appearance of MRI has gradually decreased.
6. Digital subtraction angiography (DSA): It can distinguish whether the tumor is from blood vessels or the relationship with blood vessels, and it is helpful for the diagnosis of aneurysms, ventricular aneurysms and pulmonary artery dilation.
7. Upper digestive tract barium meal: It is helpful for the relationship between the posterior mediastinal lesion and the esophagus. If the lesion is from the esophagus or the lesion is pressed, the esophagus is displaced, and the negative rate of sputum is higher.
8. Radionuclide scanning: The positive rate of 131I scan for intrathoracic thyroid is 54.5%88.9%, and the positive rate of this hospital is over 80%. Xu Yiyuan uses 131I MIBG (iodobenzidine) to scan benign and pheochromocytoma. The specific malignancy was 97.1% and 100%, respectively.
9. B-ultrasound: B-mode ultrasound can obtain CT-like transverse tomographic images. Currently, endoscopic techniques are used to examine the mediastinum through the esophagus. The relationship between esophagus and mediastinal lesions can be understood, but this examination is not universal.
Diagnosis
Diagnosis and differentiation of mediastinal cysts and tumors
diagnosis
For the diagnosis of mediastinal tumors, besides mediastinal masses, benign or malignant should be identified in order to develop a treatment plan, but it is often difficult in practice. Generally speaking, benign tumors grow slowly, except for adhesions with nearby structures. The edges are clear, smooth and intact, especially those with cystic shape, mostly round or oval, while malignant tumors have obvious lobulated contours. When the tumor breaks through the envelope, its outline is often blurred or Roughness, the mediastinum on both sides increases at the same time, and the bone destruction is a malignant tumor. Although the neurogenic benign tumor can cause the adjacent bone compression damage, it does not cause bone structure damage, such as anemia in the sick child, weight Reduced and intermittent low fever or local severe pain, is a sign of malignant tumors. Regular X-ray examination, such as the tumor growth may be malignant, but benign tumors can also increase rapidly due to infection or bleeding, long-standing primitives Benign tumors are suspected of malignant changes, without histological examination, it is not easy to finalize the diagnosis, such as tumor shadow reduction after a small amount of X-ray irradiation, it is likely to be malignant Tumors, especially malignant lymphoma, on the neck or supraclavicular lymph nodes biopsy, diagnosis.
In the diagnosis of pediatric mediastinal tumors, esophagus and bronchoscopy and mediastinal angiography are usually not required.
Differential diagnosis
Typical mediastinal cysts and tumors are easier to diagnose, but there are more lesions in the mediastinum, so primary mediastinal tumors and cysts should be differentiated from many diseases, which is important for treatment.
1. Mediastinal lymph node metastases: multiple secondary to the lungs, gastrointestinal tract, kidney, testis, cervix, breast and other malignant carcinomas, often multiple, even single isolated in the mediastinum, X-ray more in the mediastinal side Round, oval, lobulated, irregular, dense shadows, sharp edges, can be identified based on the history of primary tumors and other clinical manifestations.
2. Intrathoracic thyroid: mostly goiter, thyroid cyst or adenoma, benign mostly, and acquired the same, related to the thyroid gland, extending from the neck thyroid to the anterior superior mediastinum, generally asymptomatic, if increased, resulting in oppression There may be poor breathing, wheezing and sternal discomfort. The 131I scan is helpful for the diagnosis of intrathoracic thyroid. X-ray films show the shadow of the anterior superior mediastinum, and the upper mediastinum is bilateral or bilateral. The density is uniform and the edges are smooth. It may also be slightly lobulated, may have calcification, the lesion is in front of the trachea, the trachea can be pushed to the side or the back, the annular wrap can also make the trachea narrow, and the mass can be touched up and down at the sternal notch.
3. Malignant lymphoma: malignant lymphoma originating in the mediastinum is rare, mostly for systemic malignant lymphoma mediastinal invasion, clinical fever, cough, chest tightness, chest pain, weakness, night sweats, and upper vena cava syndrome may also occur. The lesions are mostly located next to the trachea, under the carina, and the X-ray shows the shadow of the mass protruding to one side or both sides of the mediastinum, lobulated, mostly in the mediastinum, anterior mediastinum, less in the posterior mediastinum, and late lesions can invade the lungs. And the heart, most can be diagnosed, the diagnosis is difficult to determine (can not take biopsy), if one or two chemotherapy lesions shrink rapidly, it is easy to diagnose the disease.
4. Mediastinal lymph node tuberculosis: the symptoms are not obvious, mostly young and middle-aged patients, often have fatigue, cough, night sweats, low fever, loss of appetite, weight loss, X-ray lesions are mostly located on one side of the mediastinum, more on the right, round , oval shadow, the author has reported that the shadow sharpness is better than the lateral position, the erythrocyte sedimentation test is more than 40mm / h, the skin OT test is mostly positive.
5. Mediastinal lymphadenitis or granuloma: There are many causes of mediastinal lymph node granuloma, tuberculosis is mostly, in addition to histoplasmosis, tuberculosis and silicosis, etc., the incidence of this disease is mostly in the middle, young, long course, generally The condition is good, there may be cough, fever, headache, chills, poor breathing. In recent years, tuberculosis has a slight upward trend in this disease. It is characterized by a mediastinal round shape, oval or lobulated shape, and the edges are smooth and uniform, even if No primary tumor, elimination of tuberculosis, use of hormones, sarcoidosis can get quite good results.
