Mediastinal cysts and tumors in children

Introduction to pediatric 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 mainly thymus and mediastinal lymphoid tissue. basic knowledge Sickness ratio: 0.0012% Susceptible people: children Mode of infection: non-infectious Complications: septic shock

Pediatric mediastinal cyst and tumor etiology

(1) Causes of the disease

Teratoma (35%):

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.

Lymphoma (27%):

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 (16%):

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 (7%):

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.

1. Thyroid tumors Intrathoracic thyroid tumors are mostly 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.

2. Bronchocysts and digestive tract cysts During embryonic development, such as partial cell ectopic in the foregut, cysts are formed. The inner membrane of the cyst is ciliated columnar epithelial cells, similar to the bronchial mucosa, called bronchial cysts, such as with esophagus and Gastrointestinal mucosa is similar, called digestive tract cyst. There are 5 bronchial cysts in the above 119 cases, located behind the bronchial bifurcation, in front of the esophagus, sometimes deformed with breathing, and the digestive tract cyst is also considered to be an important malformation of the digestive tract. Most of them are located in the right posterior mediastinum and the esophagus is close to the appendage. If the covered gastric mucosa has ulcers and inflammation changes, it may also break into the trachea and bronchi.

3. Neurogenic tumors are mostly located in the posterior mediastinum. Common neuroblastoma, neurofibromatosis, ganglioneuroma and pheochromocytoma, and neuroblastoma and neurofibroma can form a dumbbell shape. The rib groove extends from the intervertebral foramen into the spinal canal.

(two) pathogenesis

1. The shape of the mediastinum 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, and the mediastinum is short and wide. The mediastinum can change with the breathing movement. The mediastinum is elongated during inhalation, and the mediastinum is shortened in the supine position and exhalation.

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.

Pediatric 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) that can help us avoid or minimize exposure to harmful substances.

2. Improve the immunity of the body against tumors, and help to strengthen and strengthen the body's immune system and cancer.

Mediastinal cysts and tumor complications in children Complications septic shock

Can be complicated by infection, can cause jugular vein engorgement, can cause difficulty in swallowing, hoarseness and so on.

Children with mediastinal cysts and tumor symptoms Common symptoms Low fever, severe pain, hoarseness, dyspnea, slow breathing, slow jugular vein dysfunction, swallowing, bone destruction, edema

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.

Examination of mediastinal cysts and tumors in children

Peripheral blood samples were examined for concurrent infections. White blood cell counts and neutrophils were significantly increased in peripheral blood, and hemoglobin and red blood cell counts were reduced, 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 lateral radiograph are the main diagnostic methods for mediastinal tumor. The perspective can be rotated at any position. The shape, size and relationship between the mass and the surrounding area of the tumor are observed from various aspects. Whether the tumor is pulsating or not is swallowed. 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. The fault (body layer) film can show the level structure of the tumor and its relationship with the surrounding organs or tissues. It can still be determined whether there is space and micro-calcification in the lesion to make up for the deficiency of the flat piece.

3. CT scan CT is one of the non-invasive 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, swollen in the hilar area 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) is more clear than CT in the mediastinum. It does not require contrast agent 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 and Chest examinations are currently more valued.

5. Sonic photography 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) can distinguish whether the tumor comes 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. The upper digestive tract barium meal helps the relationship between the posterior mediastinal lesion and the esophagus. If the lesion is from the esophagus or the lesion compresses the esophagus, the negative rate is higher.

8. The positive rate of radionuclide scanning 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 for benign and pheochromocytoma. The malignancy was 97.1% and 100%, respectively.

9. B-ultrasound B-mode ultrasonography can obtain CT-like transverse tomographic images. Currently, the use of endoscopic techniques to examine the mediastinum through the esophagus can be used to understand the relationship between esophagus and mediastinal lesions, but this examination is not universal.

Diagnosis and differentiation of mediastinal cysts and tumors in children

diagnosis

Radiographic examination: including posterior anterior, lateral or oblique photos, posterior mediastinal tumors can be used for esophageal barium meal imaging, sometimes for tomography.

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.

Clinically, according to the projection of the organs and tissues in the mediastinum, the mediastinum is divided into the anterior, middle and posterior parts, the sternum, the heart, the ascending aorta and the trachea, and the narrow inverted triangular region is the anterior mediastinum; the heart, the aortic arch, The trachea, hilar and esophagus occupy the middle mediastinum; the posterior esophagus and the paraspinal sulcus are the posterior mediastinum, and the above-mentioned mediastinal partition and various parts are prone to tumors.

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 are often secondary to lung, gastrointestinal tract, kidney, testis, cervix, breast and other malignant carcinomas, often multiple, even isolated in the mediastinum, X-ray more in the middle of the mediastinum Round, oval, lobulated, irregular, dense shadow, sharp edge, can be identified according to the history of primary tumor and other clinical manifestations.

2. The intrathoracic thyroid is mostly goiter, thyroid cyst or adenoma, benign mostly, and the acquired person is also more, related to the thyroid gland, extending from the neck thyroid to the anterior superior mediastinum, generally asymptomatic, if increased, can produce oppression Poor breathing, wheezing and sternal discomfort, 131I scan is helpful for the diagnosis of intrathoracic thyroid gland. X-ray films show the shadow of the anterior superior mediastinum, and the upper mediastinum or both sides protrude, the density is uniform, and the edges are smooth. It can also be slightly lobulated, with 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. The sternum can be touched up and down.

3. Malignant lymphoma is rare in the mediastinal malignant lymphoma, mostly for systemic malignant lymphoma mediastinal invasion, clinical fever, cough, chest tightness, chest pain, weakness, night sweats, upper vena cava syndrome, lesions Mostly located next to the trachea, under the carina, 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, advanced lesions can invade the lungs and Most of the heart can be diagnosed. If the diagnosis is difficult to determine (no biopsy can be taken), if the lesion is rapidly reduced once or twice, it is easy to diagnose the disease.

4. The symptoms of mediastinal lymph node tuberculosis are not obvious, mostly young and middle-aged patients, often with 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 side, 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, and the skin OT test is mostly positive.

5. Mediastinal lymphadenitis or granuloma cause mediastinal lymph node granuloma for many reasons, mostly tuberculosis, in addition to histoplasmosis, tuberculosis and silicosis, etc., the incidence of this disease is mostly in the middle, young, long course, general condition Well, there may be cough, fever, headache, chills, poor breathing. In recent years, tuberculosis has a slight upward trend in this disease, which is characterized by a mediastinal round, oval or lobulated, smooth and tidy edges, uniform, if not The primary tumor, the elimination of tuberculosis, the use of hormones, sarcoidosis can get quite good results.

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