Mediastinal nerve sheath tumor

Introduction to mediastinal nerve sheath tumor Neurogenic tumors are the most common mediastinal tumors in adults and children. The tumors are classified into benign tumors such as schwannomas, melanoma, Schwannoma, granulosa cell tumors and neurofibroma. Malignant tumors have malignant Schwannoma and neurogenic sources. Sarcoma. basic knowledge The proportion of illness: 0.003% Susceptible people: no specific population Mode of infection: non-infectious Complications: epidural abscess

The cause of mediastinal sheath-derived tumor

Causes:

Schwannomas (20%):

The Schwann cells from the nerve sheath grow slowly. On the naked eye, the sphincter envelope is completely adhered to the originating nerve fibers. It is hard, grayish yellow or pink, and the cut surface is like an annual ring. It can be seen under the microscope. Two kinds of cells: Antoni A is a spindle-like cell, which is dense and avascular. It has a change of myxoma and multiple cystic areas. The vessel wall is thickened and hyaline degeneration. There are many electron microscopic observations of Antoni A cells. The small cytoplasmic processes emitted by the cell body, Antoni B cells lack these cytoplasmic processes, but are rich in cytoplasm and complex organelles.

Schwann cell tumors containing melanin occur in the spinal canal in addition to the paraspinal sulcus, and granuloma is the origin of sphincter cells. Aisner et al. (1988) reported a simultaneous granulocyte in the paraspinal sulcus. tumor.

Neurofibromatosis (20%):

Compared with schwannomas, neurofibromatosis is composed of nerve cells and nerve sheaths. It appears to have a capsule on the naked eye. The cut surface is gray and translucent, with small round or fusiform swelling, but no real connective tissue can be seen under the microscope. Boundary, histologically, the proliferating cell membrane sheath and many axons form a staggered network. The cells are not arranged in a grid. Under electron microscopy, the tumor is composed of elongated cells that protrude from a few large cytoplasmic processes. Occasionally, myelinated or unmyelinated axons are seen in the collagen matrix.

The plexiform neurofibroma is a diffuse fusiform enlargement of the nerve and/or multiple masses distributed along the nerve. The sympathetic trunk of the paraspinal sulcus, the vagus nerve, and the phrenic nerve are all visible, but the left vagus nerve is near. The lateral ends, ie above the aortic arch or the level of the aortic arch are more common.

Neurogenic sarcoma (10%):

(Malignant Schwann cell tumor) Less than 10% of adult neurogenic tumors are neurogenic sarcomas, tumors are located in the posterior mediastinum, and can be seen in the anterior mediastinum; nearby structures are often violated and can occur far At the site of the transfer, the number of cells was abnormally increased under the microscope, and nuclear polymorphism and mitosis were observed.

Pathogenesis

The schwannomas are derived from the nerve sheath cells, which occur in the posterior and intercostal nerves of the spinal nerves. They can also occur in the sympathetic and vagus nerves. The recurrent laryngeal nerves are similar in men and women. They occur in people 20 to 50 years old. The difference occurred in the upper part of the chest more than below, the size of the tumor is different, usually ranging from 3 to 15 cm in diameter (median value 5.0 cm), single hair more than multiple, benign nerve sheath tumor can be divided into two categories: nerve Schwannoma (benign Schwannoma) and neurofibromatosis, rare melanoma Schwannoma and granulosa cell tumor, malignant schwannomas or neurogenic sarcoma, schwannomas mostly located in the nerve trunk One side, wrapped in a nerve outer garment or clothing, makes the nerve trunk eccentric fusiform expansion, but the nerve does not penetrate into the tumor, so the operation is easy to remove, does not damage the nerve, neurofibromatosis occurs mostly in 20 to 40 years old, Mostly part of the Von Reckling-hausen disease of neurofibromatosis, the main cellular component is also the nerve sheath cells, which are tumor-like masses formed by localized or diffuse hyperplasia of peripheral nerve fibers, intrathoracic mediastinum The tumor is often single-shot. The malignant rate of neurofibromatosis in this type of patient can be as high as 4% to 10%. The nerve sheath-derived tumor of the spinal nerve root and intercostal nerve can expand and expand in the intervertebral foramen. The tumor outside the intervertebral foramen is often larger than the inner part of the intervertebral foramen. Occasionally, two uncommon sphincter tumors are seen in the mediastinum: melanoma schwannomas, granulocyte tumors, which are confirmed to originate from neuronal cells. It is a malignant lesion and is classified as a malignant schwannomas. Neurogenic sarcoma (malignant Schwann cell tumor) accounts for less than 10% of adult neurogenic tumors. It is more common in young people aged 10 to 20 or 60 to 70 years old. In the elderly, the structure near the tumor is often violated, and distant metastasis can occur. Under the microscope, the number of cells is abnormally increased, nuclear polymorphism and mitosis.

Mediastinal nerve sheath tumor prevention

There is no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of this disease.

Mediastinal nerve sheath tumor complications Complications, epidural abscess

1. Epidural hematoma: paravertebral muscles, vertebrae and dural venous plexus are not completely hemostasis, hematoma can form after operation, resulting in limb paralysis, which occurs within 72 hours after surgery, even in the case of drainage tube Hematoma can also occur. If this phenomenon occurs, it should be actively explored to remove the hematoma and completely stop bleeding.

2. Spinal cord edema: often caused by surgical operation of the injured spinal cord, clinical manifestations similar to hematoma, treatment with dehydration, hormones, severe cases can be operated again, open dura.

3. Cerebrospinal fluid leakage: mostly caused by the dural and muscle layer suture is not tight, if there is drainage, the drainage tube should be removed in advance. If the leakage is less, the drug change can be observed. If the leakage cannot be stopped or the leakage is excessive, the fistula should be sutured in the operating room.

Mediastinal nerve sheath tumor symptoms Common symptoms Brachial plexus involvement Acute pain Spinal cord compression Neck sympathetic chain involvement Tracheal and mediastinal displacement Hypoxemia Dysphagia Chest tightness Breathing difficulties Acute dyspnea

Nerve sheath-derived benign tumors, mostly asymptomatic, are often found on routine chest X-rays, while in a few patients the symptoms are often caused by mechanical causes, such as chest or back pain due to intercostal nerves, bone or chest wall Pressing or being infiltrated, coughing and breathing difficulties are caused by bronchial tree compression, Pancoast syndrome is involvement of brachial plexus, Horner syndrome is involved in cervical sympathetic chain, hoarseness is tumor invasion of recurrent laryngeal nerve, 3% to 10% Patients with tumors protruding into the spine, dumbbell-shaped swelling in the spinal canal can occur spinal cord compression symptoms, lower limb numbness, movement disorders, although 60% of patients with dumbbell-shaped tumors have symptoms associated with spinal cord compression, but There is still some asymptomatic. When the tumor grows hugely or malignantly, it can occupy one side of the chest cavity, and the mediastinum shifts to the healthy side. The patient's lungs are completely compressed by the tumor and have no function. Gradually, chest tightness, shortness of breath, and symptoms increase after the activity. Can cause wheezing, partial depression after lung compression, recurrent lung infection, cough, phlegm, fever, some may have acute dyspnea, and Displace the trachea, the respiratory sound of the affected side disappears, blood gas analysis suggests hypoxemia, due to the displacement of the heart, tumor compression of the superior vena cava can occur in the superior vena cava syndrome, compression of the esophagus can occur dysphagia, generally from asymptomatic There are symptoms ranging from 3 months to 3 years. It has been reported for up to 14 years. The malignant nerve fibroma is rarely seen. The growth of malignant schwannomas is often early and the symptoms are often heavier. Often, severe pain occurs due to tumor invasion of adjacent tissues.

Examination of mediastinal nerve sheath tumor

1. The neurogenic tumors seen in chest X-rays are basically similar, and there are no obvious differences between benign and malignant manifestations. The orthotopic X-ray films show circular or elliptical uniform shadows in the thoracic cavity, and occasionally triangular or lobulated, The inner edge is often located in the mediastinum, and the lateral slice shows that the tumor is located in the paraspinal area of the spine, the boundary is clear, and adjacent bones may also change.

Such as: ribs and vertebral body erosion, increased intervertebral foramen, widened intercostal space, and valgus eversion, but often can not explain the nature of the tumor, because the tumor growth caused by local compression, pedicle flattened Even the pedicle transverse vertebral body is destroyed, accompanied by the expansion of the intervertebral foramen, which is a special X-ray sign of the posterior mediastinal dumbbell-shaped tumor. The upper digestive tract tincture tablet also shows the distortion of the esophagus.

2. CT scan showed that the tumor was located in the posterior mediastinum, close to the paravertebral, the tumor boundary was clear, round, oval, and some cases of benign or malignant tumors could have lobes. In patients with multiple neurofibromatosis, the detection rate of CT scan is often higher than that of ordinary chest X-ray.

3. Magnetic Resonance Imaging (MRI) Enhanced images of T1 and T2 can show that neurofibromatosis has a high-density characteristic peripheral zone and a medium-density central zone, while schwannomas are heterogeneous high-density zones, CT or MRI can determine the extent of tumor invasion into the spinal canal, which can also be used to determine the extent of involvement. However, enhanced spinal X-ray examination is currently used to understand tumor invasion, such as a giant neurogenic tumor on one side of the chest. X-ray films and CT films can show that huge tumors occupy the entire thoracic cavity, the mediastinum shifts to the healthy side, the trachea is displaced, compressed or narrowed, the affected lung is compressed, and the common intra-thoracic effusion is common.

Diagnosis and diagnosis of mediastinal nerve sheath tumor

The age of onset of sphincter-derived tumors is 20-50 years old, occasionally seen in children. The incidence is similar between men and women, but neurogenic sarcoma tends to occur in patients with benign schwannomas at both ends, 10-20 Age and 60-70 years old age, after understanding the medical history, it is difficult to diagnose according to clinical manifestations. The diagnosis depends mainly on postoperative pathological examination.

Neurofibromatosis with intrathoracic neurofibromatosis must be differentiated from rare meningeal protrusions, which is not difficult to diagnose because of its peripheral neurofibromatosis.

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