primary mediastinal tumor
Introduction
Introduction to primary mediastinal tumor The primary mediastinal tumor (primary mediastinal tumor) includes tumors and cysts produced by various tissues and structures in the mediastinum. Primary mediastinal tumors are most common with thymoma, followed by neurogenic tumors and teratomas: others such as cysts. Intrathoracic thyroid, bronchial cysts are relatively rare. Most of these tumors are benign, but there is a possibility of malignant transformation. basic knowledge The proportion of illness: 0.0021% Susceptible people: no special people Mode of infection: non-infectious Complications: myasthenia gravis
Cause
Primary mediastinal tumor
The disease is a congenital tumor, mainly caused by abnormal development during the embryonic period. The etiology and pathology of the disease are as follows:
[pathology]
(A) The most common upper mediastinal tumors are thymoma and intrathoracic thyroid tumor.
The mediastinum is located in the center of the thoracic cavity, from the chest entrance, to the diaphragm, to the mediastinal pleura, and to the sternum and thoracic vertebrae. The area above the sternal angle is called the superior mediastinum. The pericardium is called the anterior mediastinum. In the mediastinum, the interosseous spine is called the posterior mediastinum.
1. The thymoma is mostly located in the anterior superior mediastinum or anterior mediastinum, accounting for 1/4 to 1/5 of the primary mediastinal tumor. The incidence is equal in men and women, 30% is malignant, 30% is benign, and 40% is potential or low. Malignant, benign people are often asymptomatic, even when X-ray examination, if the tumor volume is small, the density is light, close to the sternum, X-ray examination is difficult to find, thymoma is more adjacent to the ascending aorta, so There are obvious conductive beating, according to histological features can be divided into lymphocyte type, epithelial reticular cell type, epithelial cells and lymphocyte mixed type, common epithelial cells and lymphocytes predominant benign thymoma, if surgical resection Incomplete, there is the possibility of recurrence and infiltration and metastasis. Postoperative radiotherapy should be given. Malignant thymoma is easy to invade the surrounding tissue, and there may be varying degrees of post-sternal pain and shortness of breath. Late patients may develop blood vessels and symptoms of nerve compression. As above, vena cava obstruction syndrome, diaphragmatic paralysis, hoarseness, etc., about 10% to 75% of patients with thymoma may have symptoms of myasthenia gravis, but only 15% to 20% of patients with myasthenia gravis have thymic lesions. About 2/3 after resection of the tumor The patient's symptoms of myasthenia gravis are improved, and a small number of patients may develop aplastic anemia, hypercortisolism, lupus erythematosus, gamma globulin deficiency and idiopathic granulomatous myocarditis, X-ray examination, see the anterior superior mediastinum To a circular or elliptical block shadow, the benign person has a clear and smooth outline, a complete capsule, and often cystic changes: the malignant contour is rough and irregular, and may be accompanied by a pleural reaction. The thymoma surgery has a good resection effect.
2. Intrathoracic goiter includes congenital vagus thyroid gland and acquired posterior sternal thyroid gland. The former is rare. It is a thyroid tissue that remains in the mediastinum during the embryonic stage. It develops into a thyroid tumor. It is completely inside the chest and has no position. The latter is a neck. The thyroid gland extends into the anterior superior mediastinum along the sternum. Most of them are located in front of the trachea. A few are in the posterior trachea. Most of the thoracic goiter is benign. In some cases, adenocarcinoma can be used. The tumor can be pulled or compressed, and it can have irritating cough. Shortness of breath, these symptoms may increase when lying on the back or head and neck turning to the lateral position, chest tightness or spinal column compression may occur chest tightness, back pain, occasionally hyperthyroidism symptoms, severe cough, hemoptysis, hoarseness, should consider malignant For the possibility of goiter, about half of the patients can have a nodular goiter in the neck. X-ray examination shows the anterior superior mediastinum, which is oval or fusiform, with a clear outline, mostly biased to the mediastinum side. Both sides bulged, and if calcified tumors are seen on plain films, they have diagnostic value. In most cases, there is tracheal compression and tumor shadows. Upwardly moving signs.
(B) anterior mediastinal tumors in the anterior mediastinal tumors are more common with teratoma, can occur at any age, but half of the symptoms appear between the ages of 20 to 40, histologically abnormal or abnormal embryogenesis Teratoma can be divided into two types:
1. The dermoid cyst is a fluid-containing cyst. The sac has skin, hair, teeth, etc. originating from the ectoderm. It is often a single room, but also has two or more rooms. The wall of the capsule is composed of fibrous tissue, and the inner wall is covered with multiple layers of scales. Epithelial.
2. Teratoma is a kind of substantial mixed tumor, composed of external, middle and inner three germ layers. It contains cartilage, smooth muscle, bronchus, intestinal mucosa, neurovascular and other components. The teratoma has a tendency to malignant rather than a cystoid cyst. It can often be changed into epidermoid carcinoma or adenocarcinoma. 386 cases of teratoma are reported in the literature, of which 14.2% are malignant. Two of 10 cases of teratoma in Shanghai Zhongshan Hospital are malignant, small in size, often asymptomatic, mostly in X-ray examination found that if the tumor enlarges and compresses adjacent organs, it can produce compression symptoms of the corresponding organs. If the vena cava is compressed, the superior vena cava syndrome may occur; when the recurrent laryngeal nerve is compressed, hoarseness occurs; Trachea can cause shortness of breath. When the patient is supine, the air is intensified. The cyst is broken into the bronchus. It can cough up the gelatinous liquid containing hair and sebum. The gelatinous liquid can be inhaled into the lungs. Lipid pneumonia and lipogranuloma can occur. The cyst has In the case of secondary infection, fever and toxic symptoms may occur. If the cyst rapidly increases in a short period of time, malignant transformation, secondary infection or tumor hemorrhage may occur. When the suppurative cyst breaks into the chest or pericardium, empyema may occur. Or heart Packed fluid.
Prevention
Primary mediastinal tumor prevention
For primary mediastinal tumors, except for lymphatic tumors using radiation or chemotherapy, the majority of cases should be treated surgically. Because these tumors are mostly congenital, they often produce symptoms of compression or infection. In addition, mediastinal tumors often have malignant changes. Therefore, surgical resection should be performed early on the mediastinal tumor with or without symptoms. For patients undergoing chemotherapy, the patient is mainly prepared for the following aspects before treatment:
(1) Psychological preparation First of all, according to their own conditions to understand the situation of this chemotherapy drug to do a good job; second, to understand the general knowledge of chemotherapy, to avoid psychological tension, can cooperate with qigong, listening to music and other forms to relax the nerves, eliminate tension.
(2) Pay attention to rest and diet. Before the chemotherapy, the patient should ensure sufficient sleep time every day. Generally, the adult sleep time is not less than 8 hours.
(3) Cooperate with the doctor to do some necessary examinations such as blood routine, liver function, kidney function, electrocardiogram, B-ultrasound, chest X-ray, etc., if necessary, do CT or MRI.
Complication
Primary mediastinal tumor complications Complications Myasthenia gravis
When the tumor is huge, the chest wall can be raised, the vertebrae of the sternum is widened, the local breath sounds disappear, and the trachea heart is displaced. In some special types of tumors, corresponding special signs such as myasthenia gravis, hyperthyroidism, and Horner syndrome can occur. , signs of superior vena cava obstruction and other signs.
Symptom
Primary mediastinal tumor symptoms Common symptoms Mediastinal shadow Mediastinal lymph node hyperplasia Thymus gland atrophy Back pain Lymph node enlargement hemoptysis Goiter septic hepatosplenomegaly secondary infection
The mediastinum is located in the center of the thoracic cavity, from the chest entrance, the eye reaches the diaphragm, the mediastinum is ventral, and the sternum and thoracic vertebrae are defined as the mediastinum. The area above the sternal angle is called the mediastinum. The pericardium is called the anterior mediastinum. In the mediastinum, the pericardium is called the posterior mediastinum. Common mediastinal tumors have their own sites, which is a reference for clinical diagnosis.
(1) Upper mediastinal tumors : The most common are thymoma and intrathoracic thyroid tumor.
1. Thymoma: mostly located in the anterior superior mediastinum or anterior mediastinum, accounting for 1/4 to 1/5 of the primary mediastinal tumor, equal in men and women, 30% malignant, 30% benign, 40% potential or Low-grade, benign, often asymptomatic, occasionally found on X-ray examination, if the tumor volume is small, the density is fast, close to the sternum, X-ray examination is difficult to find, thymoma is more adjacent to the ascending aorta, so Can have obvious conductive pulsation, according to histological characteristics can be divided into lymphocyte type, epithelial reticular cell type, epithelial cells and lymphocyte mixed type, common epithelial cells and lymphocytes account for high quality benign thymoma, if surgery Incomplete resection, recurrence and infiltration and metastasis, Shanghai Zhongshan Hospital reported 12 cases of thymoma, 5 cases have obvious malignant transformation, so thymoma can be considered as low-grade malignant tumor, postoperative should be given radiation therapy, malignant Thymoma is easy to invade the surrounding tissues, and can cause post-sternal pain and shortness of breath. Patients with advanced stage can produce blood vessels, symptoms of nerve compression, such as vena cava obstruction syndrome, diaphragmatic paralysis, hoarseness, etc., about 10% to 75 % thymus Tumor patients may have symptoms of myasthenia gravis, but only 15% to 20% of patients with myasthenia gravis have thymic lesions. About 2/3 of patients with myasthenia gravis have improved symptoms, and a few patients may develop aplastic disorders. Anemia, hypercortisolism, lupus erythematosus, gamma-globulin deficiency and idiopathic granulomatous specific myositis, X-ray examination, see a circular or elliptical block in the anterior superior mediastinum, benign contours are clear and smooth The capsule is intact and often cystic: the malignant contour is rough and irregular, and may be accompanied by pleural reaction. The thymoma surgery is good, and Legg analyzes the curative effect of 51 cases of thymoma. The 5-year survival rate of local infiltrates 23%, the 5-year survival rate of non-invasive patients reached 80%. Shanghai Chest Hospital reported that the 5-year survival rate of 207 cases of thymoma was 59.7%, and the 10-year survival rate was 43.4%.
2. Thoracic goiter: including congenital vagus thyroid gland and acquired posterior sternal thyroid gland. The former is rare. It is a thyroid-like tissue that remains in the mediastinum during the embryonic period. It develops into a thyroid tumor, completely in the chest, without a certain position. For the neck thyroid gland extends into the anterior superior mediastinum along the sternum, most of which are located in front of the trachea, a few in the posterior trachea, most of the thoracic goiter is benign, individual cases can be adenocarcinoma, the tumor is pulled or compressed, can be irritating Cough, shortness of breath, etc. These symptoms may be aggravated when lying down or turning to the lateral position of the head and neck. Chest muscles or spinal column compression may cause chest tightness, back pain, occasional hyperthyroidism, severe cough, hemoptysis, hoarseness, should be Considering the possibility of malignant goiter, about half of the patients can have a nodular goiter in the neck. X-ray examination shows the anterior superior mediastinum. It has an elliptical or fusiform shape with a clear outline and most of the mediastinal side. It also bulges to both sides, and if calcified tumors are seen on plain films, it has diagnostic value. In most cases, there is tracheal compression and tumor shadow Upwardly moving signs pharynx.
(B) anterior mediastinal tumor
Tumors that grow in the anterior mediastinum are more common in teratoma-like tumors and can occur at any age, but half of the cases appear between the ages of 20 and 40. Histologically, the hernia is abnormal or malformed in the embryo, and the teratoma Can be divided into two types:
Dermoid cyst
It is a liquid-containing cyst. The skin has hair, hair, teeth, etc., which originate from the ectoderm. It is usually a single room, but also has two or more rooms. The wall of the capsule is composed of fibrous tissue, and the inner wall is covered with multiple layers of squamous epithelium.
2. Teratogenic disease
It is a kind of substantial mixed tumor composed of outer, middle and inner three germ layers. It contains cartilage, smooth muscle, bronchus, thoracic mucosa, neurovascular and other components. The malignant tendency of teratoma is larger than that of the skin-like cyst. Epigenetic cancer or adenocarcinoma, 386 cases of teratoma were reported in the literature, of which 14.2% were malignant. Two of the 10 teratomas in Shanghai Zhongshan Hospital were malignant, small, often asymptomatic, and found in X-ray examination. If the tumor is enlarged and oppresses the adjacent organs, the compression symptoms of the corresponding organs may be generated. If the vena cava is compressed, the superior vena cava syndrome may occur; if the recurrent laryngeal nerve is compressed, the sound is hoarse; the trachea may be compressed. Anxiety occurs, the patient's air is intensified when the patient is supine, the cyst is broken to the bronchus, and the gelatinous liquid containing hair and sebum can be coughed up. The gelatinous liquid can be inhaled into the lungs, and acral pneumonia and lipid granuloma can occur. Infection, fever and toxic symptoms may occur. If the cyst rapidly increases in a short period of time, malignant transformation, secondary infection or tumor hemorrhage may occur. When the suppurative cyst breaks into the chest or pericardium, empyema or pericardium may occur. product .
X-ray examination of the cyst in the anterior mediastinum, the heart of the main aortic arch junction, a few high positions, close to the anterior superior mediastinum, can also be located in the anterior mediastinum, multi-directional mediastinal projection, a small number can be bulging to the sides, huge It protrudes into the posterior mediastinum, and even fills one side of the chest cavity. It is mostly round or elliptical. The edges are clear, and the calcification of the cyst wall is more common. Sometimes the teeth and broken bone shadows are visible.
(three) mediastinal tumor
Most of them are lymphatic tumors. Commonly, there are Hodgkin's disease, reticulum sarcoma, lymphosarcoma, etc., which are characterized by mediastinal lymphadenopathy, but can also invade lung tissue to form invasive lesions. Short, symptoms progress quickly, often accompanied by lymphadenopathy around the body, irregular fever, hepatosplenomegaly, anemia, etc. X-ray examination showed that the enlarged lymph nodes are located on both sides of the trachea and on both sides of the hilar, and the swollen lymph nodes can be merged into Block, uniform density, can have large lobes, but no calcification, the bronchus often emptied and narrowed.
(four) posterior mediastinal tumor
Almost all neurogenic tumors, mainly in the spinal nerve, intercostal nerve, sympathetic ganglia and vagus nerve, can be benign and malignant, benign, schwannomas, neurofibroma and ganglionoma; malignant malignant Schwannoma and neurofibrosarcoma, electron microscopy found that the ultrastructure of schwannomas and neurofibrosarcoma is similar, but the collagen content is different, most of the neurogenic tumors are located in the posterior mediastinal spinal sulcus, sometimes in the mediastinum Most of them have a capsule. The X-ray signs are smooth, round, isolated masses. The huge masses force the intercostal space to widen or the intervertebral foramen to enlarge. Sometimes the tumors protrude into the intervertebral foramen and invade the spinal canal, causing spinal cord compression. Symptoms, nerve fibers are more common in young adults, usually asymptomatic, larger tumors can produce compression symptoms, such as shoulder or back pain, shortness of breath.
(5) bronchogenic cysts
Can occur in any part of the mediastinum, mostly located in the trachea, near the bronchi, or near the bronchocondysis, bronchial cysts are mostly congenital, from the tracheal bud, more common in children under 10 years old, usually asymptomatic, if connected with the bronchus or pleura , the formation of fistula, secondary infections are cough, hemoptysis, purulent sputum, and even empyema, X-ray examination in the middle and middle of the mediastinum, near the trachea or bronchus, showing a circular or elliptical shape, uniform density, border Clear blocky shadows, with lobulated or calcium leaves, if the cyst is connected to the bronchus, the fluid level is visible.
Examine
Primary mediastinal tumor examination
The mediastinal tumor is sometimes difficult to distinguish between primary and secondary lung tumors, enlarged lymph nodes, hemangioma, etc. The commonly used examination methods are as follows.
1. X-ray inspection :
It is an important means to diagnose mediastinal tumors. The fluoroscopy can observe whether the mass moves up and down with swallowing, whether there is morphological change with breathing and whether there is pulsation, etc. Because common mediastinal tumors have their specific predilection sites, the posterior anterior and Lateral chest radiographs are often able to preliminarily determine the type of tumor. The tomographic images can accurately show the structure of the mass and its relationship with neighboring tissues and organs, to make up for the lack of flat films, and to understand the esophageal pressure by esophageal swallowing. Carbon dioxide for mediastinal inflation imaging can understand the relationship between tumors and mediastinal organs.
2. CT scan and magnetic resonance examination (MRI) :
The application of CT scan and MRI greatly improves the diagnostic accuracy of mediastinal tumors and cysts. The spatial resolution of CT is higher. It shows the signs of lesions, and the lesions and nodules are better than MRI. CT can clearly show various Lesions of lesions are the best imaging method for the diagnosis of teratomas. MRI does not require contrast agents in the differentiation of tumors and macrovascular diseases, and can accurately display the invasion of blood vessels. The images of sagittal and coronal planes can be clearly seen. The anatomy of the tumor is shown to be superior to CT in determining whether the neurogenic tumor has intraspinal or intradural expansion.
3. Ultrasound examination:
It is helpful to understand whether the tumor is cystic or solid, the specific location of the tumor and its relationship with the heart, large blood vessels, etc., and can be biopsy under its guidance.
4. Radionuclide scanning :
Suspected intrathoracic goiter, can be used as radionuclide 131 iodine scan, is helpful for the diagnosis of ectopic goiter, thyroid tumor.
5. Marker inspection :
Young patients with anterior mediastinal tumor should be examined for alpha-fetoprotein (AFP) and B-HCG. If one of them is elevated or both are elevated, it may be non-fine. Inferior malignant germ cell tumors, infants and children with posterior mediastinal (paraspinal) tumors should be examined for adrenaline and norepinephrine levels to exclude neuroblastoma.
6. Biopsy :
Methods There are mediastinoscopy, surgical exploration and percutaneous puncture. The mediastinoscopy can not only take specimens, but also estimate the possibility of tumor resection.
7, fiberoptic bronchoscopy or fiber esophagoscopy
It helps to determine the extent of bronchial compression, the extent to which the tumor has invaded the bronchial or esophagus, and thus the likelihood of surgical resection.
8, diagnostic pneumothorax
It can be judged that the tumor occurs in the chest wall or lung, in the lung or outside the lung, and the diagnostic pneumoperitone can distinguish the underarm factors, such as pulmonary sputum.
9, mediastinal gastroscopy
It is helpful to show the morphology of the anterior mediastinal tumor and to determine whether there is a mediastinal lymph node metastasis.
10, mediastinoscopy
For the clear end of the trachea, there are no enlarged lymph nodes under the carina, and the pathological diagnosis can be confirmed by clamping the living tissue.
11, cervical lymph node biopsy
Branched tube lymphangiogenesis and lymphoma are often associated with peripheral lymph nodes and cervical lymph nodes, and biopsy is helpful for diagnosis.
12, diagnostic radiotherapy
Suspected malignant lymphoma, if not confirmed by other tests, can be used for radiation therapy, malignant lymphoma is more sensitive to radiation, irradiation 20 ~ 30Gy (2000 ~ 3000rad), the tumor shrinks rapidly.
13, thoracotomy
The nature of the tumor has not been clarified by various examinations, but those who have been excluded from malignant lymphoma may be examined by the chest under the general conditions.
Diagnosis
Diagnosis and diagnosis of primary mediastinal tumor
