mediastinal cyst

Introduction

Introduction to mediastinal cyst Cystofmediastinum is a type of mediastinal masses, which is attributed to mediastinal tumors, but more people advocate it separately from mediastinal tumors. The mediastinal cyst is a benign lesion in the mediastinum. Can occur in the mediastinum of various organs, such as pericardium, trachea, bronchus, thoracic duct, lymphatics, thymus and so on. Occasionally there are hydatid cysts, acquired pancreatic cysts, and neurogenic intestinal cysts. basic knowledge The proportion of sickness: 0.2% Susceptible people: no specific population Mode of infection: non-infectious Complications: tracheoesophageal fistula

Cause

Cause of mediastinal cyst

Congenital factors (45%)

It is caused by a variety of congenital dysplasia, such as tracheal and bronchial cysts derived from trachea or bronchial sprouts, gastric cysts and gastrointestinal cysts derived from the anterior intestine, and pericardial cysts due to abnormal development of mesodermal tissues. And cystic lymphangioma, etc., such developmental abnormal cysts do not malignant.

Parasitic infection (15%)

The parasite invades the human body into the mediastinum, causing an inflammatory reaction. The inflammatory secretions, phagocytic cells, parasites and their secretions are wrapped with tissues and blood around the mediastinum to form a mass, that is, a cyst.

Pathogenesis

1. Tracheobronchial cyst: Tracheobronchial cyst is the most common type of mediastinal congenital cyst of the mediastinum, accounting for 40% to 50%. Most tracheobronchial cysts occur on the 26th to 40th day after conception, which occurs earlier. Most of the mediastinal masses are formed, and the lung masses are formed in the later cases. Individual cases are also found in the transverse or transverse iliac crest. The mediastinal tracheobronchial cyst can be divided into tracheal and bulge according to the location. There are 5 groups around the hilar, adjacent to the esophagus and other parts, most of which are located around the carina, and many pedicles are connected with the atmosphere. The cysts around the carina are prone to clinical symptoms due to compression of adjacent tissues.

2. Esophageal cyst: The esophageal cyst is derived from the embryonic foregut and is the result of failure to form a normal lumen during esophageal development.

3. Gastrointestinal cysts: Gastrointestinal cysts are rare. There are several kinds of explanations about their origins. Most of them are caused by the early separation of endoderm and notochord. The lining cells of gastrointestinal cysts include gastric mucosal epithelial cells and small intestine. Epithelial cells and ciliated columnar epithelial cells, etc., wherein gastric epithelial cells may have a secretory function, leading to peptic ulcer.

4. Pericardial cysts: most of the pericardial cysts are congenital diseases. In some cases, pericardial cysts can occur after many years of acute pericarditis. Pericardial cysts are usually fusiform or oval, with thin walls and clear or straw yellow. The liquid, the wall of the capsule is covered by a single layer of flat or columnar cells, and the cell morphology resembles mesothelial cells.

5. Thymic cysts: Thymic cysts are rare, accounting for only 1% to 2% of all mediastinal masses, mostly congenital cysts from the thymic pharyngeal epithelium, which can occur in the thymus descending line from the neck to the anterior mediastinum. Anywhere; there are also individual reports related to surgical trauma, inflammation and so on.

Pathologically, thymic cysts should be differentiated from pseudocysts formed by thymoma and Hodgkin's disease. The pseudo-cyst wall is generally thick, and residual tumor tissue can be found in the fibrous wall.

Prevention

Mediastinal cyst prevention

1, the diet should pay attention to light, mostly with food porridge, noodle soup and other foods that are easy to digest and absorb.

2, can eat more fresh fruits and vegetables to ensure the intake of vitamins.

3, give liquid or semi-liquid food, such as a variety of porridge, rice soup and so on.

4. Develop good hygiene habits to prevent parasitic infections. If the parasite has been infected, it should be treated promptly to prevent the occurrence of mediastinal cysts.

Complication

Mediastinal cyst complications Complications of tracheoesophageal fistula

Gastrointestinal cysts, etc. can be complicated by complications such as tracheobronchial fistula, esophageal fistula, and thoracic vertebrae destruction.

Symptom

Mediastinal cyst symptoms common symptoms mediastinal lesions dyspnea persistent cough squamous epithelial dysphagia

1. Tracheobronchial cyst: The clinical manifestations of the tracheobronchial cyst in the mediastinum are mainly related to its location. The cyst located around the carina can cause obvious clinical symptoms when the volume is not large, while the cysts in other parts can grow to a large extent. There are still no obvious clinical manifestations. Common clinical symptoms include dyspnea (especially during activity), persistent cough and wheezing. Children are easily misdiagnosed as asthma, wheezing bronchiolitis, tracheobronchial stenosis or airway foreign body. The cysts and the airway are easy to be infected and have corresponding clinical manifestations. Individual cases of cysts can cause obstruction of the trachea or obstruction of the right ventricular outflow tract.

2. Esophageal cyst: the non-keratinized squamous epithelium is lining the wall of the capsule. There are double-layer smooth muscles. It can be seen that the esophageal glands sometimes have a small range of ciliated columnar epithelium, which may be similar to the fetal esophageal structure covering the cilia epithelium. The structure of the bronchi, the absence of cartilage in the wall is helpful for identification. The esophageal cyst is mostly located next to the esophagus. Most patients are asymptomatic. A small number of patients have difficulty swallowing due to oppression of the esophagus. Some patients may be misdiagnosed as asthma or chronic bronchitis due to chronic cough.

3. Gastrointestinal cysts: Men with this disease are more common, clinical symptoms appear earlier, more clinical manifestations than children or earlier, including pain, dyspnea, cough, vomiting, weight loss, hemoptysis, etc., gastric mucosa in the capsule Epithelial cells secrete acidic substances and certain proteases, causing ulceration of the cyst wall, and may involve adjacent tissues, forming fistulas in the tracheobronchial and esophagus, causing corresponding clinical symptoms.

4. Pericardial cysts: Most pericardial cysts do not cause clinical symptoms. They are only caused by routine physical examination or chest X-ray examination for other reasons. Individual patients have sternal pressure and dyspnea due to excessive cyst compression of adjacent structures. Cough and other symptoms; very few reported pericardial cyst secondary infection.

5. Thymic cysts: Most of the patients are children and young people, most of them have no clinical symptoms. They are only found on chest X-ray examination for other reasons. A small number of cysts can cause chest pain or nausea, cough, and difficulty breathing. Dysphagia, hoarseness and other symptoms.

Examine

Examination of mediastinal cyst

Peripheral blood: normal.

Tracheobronchial cyst

Chest X-ray examination is common in the vicinity of the common carina, the uniform mass of the mediastinum mass, mostly round or oval, its shape can change with respiratory movement, can also be seen in other parts of the mediastinum, generally no lobulation, Without calcification, the cyst under the carina can increase the angle of the bulge.

The esophageal cyst examination showed that the esophagus was obviously under pressure, and the secondary infection with the airway showed that the cyst expanded in a short period of time, and a gas-liquid level may appear.

Chest CT scan can determine the location of the cyst and its relationship with the surrounding structure. The typical cyst is round or oval, CT value is 0 ~ 20HU, the wall is very thin; CT value of liquid protein content in the cyst cavity is high Increased, repeated chronic infection of the wall can be thickened.

2. Esophageal cyst

Chest X-ray examination showed that the lesion was located in the anterior mediastinum of the posterior mediastinum, round or oval, with clear boundaries.

Esophageal swallowing examination showed obvious pressure on the esophagus, but the mucosal folds were intact. For example, the cyst was ulcerated and connected with the esophagus. Gas was found in the cyst. When swallowing, the expectorant entered the cyst.

The esophageal cyst and the bronchial cyst located next to the esophagus have the same X-ray findings, which are difficult to identify and often require a postoperative pathological examination to confirm the diagnosis.

3. Gastrointestinal cyst

Chest X-ray examination showed that the cyst was located next to the mediastinal spine, round or elliptical, with a clear and uniform outline and uniform density.

Esophageal cysts are often connected to the meninges and gastrointestinal tract through the pedicle. If the joint is located in the thoracic esophagus, there is no traffic. On the contrary, if the joint is located in the abdominal gastrointestinal tract, most of the traffic is there, and air can enter. In the cystic cavity, the sputum can also enter the sac cavity during angiography. The thoracic vertebrae and cervical vertebra deformity, such as the semi-spinal deformity, posterior spine, and scoliosis, are often seen.

4. Pericardial cyst

Chest X-ray examination showed that the pericardial cyst is usually located in the anterior mediastinal palpebral palpebral area, but there are also higher positions. A few patients can extend to the upper mediastinum. The right side is more common than the left side. The cyst is clearly smooth and uniform in density. Calcification, sometimes in the lateral chest radiograph, the cyst is a drop-shaped shadow on the tip of the drop, which may be formed by the interstitial fissure embedded in the cyst. It has certain characteristics. Most cysts are between 3cm and 8cm in diameter, but there are also Reports as small as 1 cm and as large as 28 cm.

CT examination helps to define the cystic structure of the shadow, and the diagnostic value is higher for those located in atypical areas. The shape of the cyst under fluoroscopy may vary with position changes and respiratory movements.

5. Thymic cyst

Chest X-ray examination showed no specific manifestations, the cyst edge was smooth, round or oval, located in the anterior mediastinum, CT and magnetic resonance examination helped to identify cystic features.

Diagnosis

Diagnosis and differentiation of mediastinal cyst

According to the medical history, comprehensive analysis of clinical symptoms and signs, often need to use CT to confirm the diagnosis.

Mediastinal cysts need to be differentiated from mediastinal tumors; such as thoracic aortic aneurysm or multiple aneurysms, paraspinal abscess, central lung cancer, mediastinal lymphatic tuberculosis, pulmonary suppuration, ventricular aneurysm, etc.

1. Aneurysms are divided into true, pseudo and dissecting aneurysms, mostly caused by arteriosclerosis or trauma. The syphilis is rare, which can occur in the carotid artery, subclavian artery, radial artery, radial artery, radial artery and radial artery. Femoral artery and radial artery are the sites of femoral artery and radial artery.

2. Abscess is a localized pus accumulation in the tissue, organ or body cavity due to necrosis and liquefaction of the diseased tissue during acute infection. There is a complete pus wall around it.

The common pathogen is Staphylococcus aureus. The abscess can be caused by an acute suppurative infection, or by a pathogen of a distant source of infection through the bloodstream or lymphatic vessels. It is often caused by necrosis and dissolution of inflammatory tissue under the action of toxins or enzymes produced by bacteria, forming a abscess cavity, exudate in the cavity, necrotic tissue, pus cells and bacteria to form a pus.

3. Lung cancer is the most common malignant tumor in the lungs. The vast majority of lung cancer originates from the bronchial mucosa epithelium, so it is called bronchial lung cancer.

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