spinal cord schwannoma
Introduction
Introduction to spinal schwannoma Spinal schwannomas originate from the dorsal spinal nerve roots and can also produce subdural infiltration during centripetal growth. Brachial plexus or lumbar plexus neurofibroma can be invaded along the central nerve into the central dura, and the Schwann cell tumor of the paravertebral is usually located outside the epidural when it extends into the spinal canal. About 2.5% of the intradural spinal schwannomas are malignant. basic knowledge The proportion of illness: the incidence rate is about 0.004%-0.005% Susceptible people: no special people Mode of infection: non-infectious Complications: edema, dehydration, cerebrospinal fluid leakage
Cause
Cause of spinal schwannoma
(1) Causes of the disease
Quite a number of viewpoints suggest that the occurrence and growth of tumors are mainly caused by molecular changes at the gene level. Many cancer formations are thought to be caused by loss of normal tumor suppressor genes and activation of oncogenes. Two types of neurofibromatosis have been Widely studied, genetic studies suggest that NF1 and NF2 genes are located on the long arm of chromosomes 17 and 22, respectively. Both types of neurofibromatosis are autosomal dominant and have a high penetrance, NF1. The incidence is approximately 1 in 4000 births, half of which are scattered cases, caused by newer mutations. In addition to spinal nerve fibroma, NF1 clinical manifestations include caffeine pigmentation, skin nodules, skeletal abnormalities, subcutaneous neurofibroma, surrounding Plexid plexiform neuroma, complicated by some common tumors in children, such as optic nerve and hypothalamic glioma, ependymoma, intraspinal neurofibromatosis is less than neurofibromatosis occurring outside the spinal canal, NF1 gene coding Neuronal fibers belong to the GTPase activator family (220-KD), and GTP proteins are involved in the down-regulation of ras oncogenes by their ligand activation. Mutation leading to a gene product formation, and thus can not effectively cause GTP deoxygenation reaction, thereby facilitating ras gene regulation, growth factors enhance the signal path, resulting in product characteristics NF1 tumors appeared, the NF1 tumor formation.
NF2 was first recognized as a unique tumor type that originated in 1970, and its incidence rate is equivalent to 10% of NF1. Bilateral acoustic neuroma is a defining feature, but other cranial nerves, spinal nerves and peripheral nerve Schwannoma are also very Commonly, skin manifestations are less common. Compared with NF1 "surrounding", NF2 seems to be more "central". The protein encoded by NF2 gene seems to mediate the interaction between extracellular matrix and intracellular framework. Regulating cell distribution and migration, this loss of tumor suppressor function appears to be a recessive feature that requires matching mutations on each NF2 allele, and sporadic Schwannoma and meningioma often produce on chromosome 22. Abnormal cell behavior, the exact mechanism of tumor formation is still under study, and recent studies by Lothe suggest that the formation of certain malignant peripheral schwannomas is associated with the inactivation of the TP53 tumor suppressor gene on the short arm of chromosome 17.
(two) pathogenesis
Schwannomas can be divided into Schwann cell tumors or neurofibromas. Although tissue culture, electron microscopy and immunohistochemistry support both neurofibroma and Schwann cell tumors have a common origin, that is, from Schwann cells, however, The morphology of neurofibromatosis suggests that other cells are involved, such as cells surrounding neurons, fibroblasts, etc. Due to differences in morphology, histology, and biological characteristics, neurofibromatosis and Schwannoma are considered to be two A relatively independent group, the histological features of neurofibromatosis are characterized by the presence of fibrous tissue and scattered nerve fibers in the tumor. In general, the tumor causes the affected nerve to produce a fusiform enlargement, and it is almost impossible to distinguish the boundary between the tumor and the nerve tissue. Multiple neurofibromas are often diagnosed as multiple neurofibromatosis. Schwann cell tumors are generally spherical and do not produce enlarged nerves, but when they are eccentrically grown and have obvious attachment points, the differential diagnosis is also Difficult, histological features of the elongated rhomboid bipolar cells, the nucleus is deeply stained and densely arranged, and the scattered stellate cells It is rare.
Prevention
Spinal schwannoma prevention
Malignant schwannomas have a very poor prognosis with a lifetime of rarely more than one year. These tumors must be differentiated from some of the few invasive histological features of Schwann cell tumors. Schwann cell tumors with a malignant tendency have a relatively good prognosis.
Complication
Spinal schwannoma complications Complications, edema, dehydration, cerebrospinal fluid leakage
Spinal schwannomas, such as surgery, may have the following complications:
Epidural hematoma
Paravertebral muscles, vertebrae and dural venous plexus are not completely hemostasis. Hematoma can form after operation, resulting in aggravation of limb paralysis. It occurs within 72 hours after surgery. Hematoma can occur even in the case of drainage tube. A phenomenon 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, the clinical manifestations similar to hematoma, treatment with dehydration, hormones, severe cases can be re-operation, open dura.
3. Cerebrospinal fluid leakage
Due to the tightness of the dural and muscle layer suture, if there is drainage, the drainage tube should be removed in advance. If the leakage is less, the drug should be changed. If the leakage cannot stop or the fluid leaks, the fistula should be sutured in the operating room.
4. Incision infection, cracking is generally poor, incision healing ability or cerebrospinal fluid leakage is easy to occur, intraoperative should pay attention to aseptic operation, postoperative antibiotic treatment, should actively improve the general condition, pay special attention to protein and various Vitamin supplements.
Symptom
Symptoms of spinal schwannomas Common symptoms Back pain, hypersensitivity, sensation, spinal cord traversal damage, temperature loss, spinal cord hemisection syndrome, paralysis, sensory dysfunction, upper cervical spinal cord lesion, slow waist, soft mass
The course of the disease is mostly long. The history of the thoracic segment is the shortest. The neck and lumbar segments are longer. Sometimes the course of disease can be more than 5 years. The tumor is cystic or bleeding.
The most common symptom of the first symptom is radiculopathy, followed by paresthesia and dyskinesia. The pain of the upper neck tumor is mainly in the neck, the shoulder and the upper arm are radiated; the tumor pain in the neck and thorax is mostly located behind the neck or upper back. And radiate to one or both shoulders, upper limbs and chest; the upper thoracic tumor often presents with back pain and radiates to the shoulder or chest; the pain of the thoracic tumor is mostly located at the thoracolumbar and can be radiated to the abdomen, groin and Lower extremities, thoracolumbar tumor pain is located at the waist, can be radiated to the groin, arms, thighs and calves, the pain of the lumbosacral tumor is located in the lumbosacral region, buttocks, perineum and lower limbs.
20% of patients with sensory abnormality as the first symptom, which can be divided into two types: hypersensitivity and hypothyroidism. The former is characterized by ant feeling, numbness, chills, soreness and burning; the latter is mostly painful, mild and tactile. Joint decline.
The dyskinesia is the third symptom in the first symptom. Due to the different parts of the tumor, radiculopathy or tract injury can cause dyskinesia. As the symptoms progress, the dysfunction of the pyramidal tract can occur. the same.
The main clinical symptoms and signs of spinal schwannomas are pain, paresthesia, dyskinesia and sphincter dysfunction. The incidence of paresthesia is about 85%, and the incidence of pain is nearly 80%.
The sensory disorder generally starts from the distal end and gradually develops upwards. The patient's early subjective feeling is abnormal, and the examination has no special findings, followed by sensory loss. Finally, all the feelings are accompanied by the loss of motor function. The conical horsetail has no spinal cord parenchyma, so the abnormal feeling It is distributed in the peripheral nerve type, and the skin of the anus and perineum is typically numb in the saddle area.
Most patients have different levels of mobility difficulties when they come to the hospital. Half of the patients have limb paralysis. The time of dyskinesia is different depending on the tumor location. The cone or ponytail tumor will show obvious movement disorder in the late stage. The tumor developed symptoms earlier.
Sphincter dysfunction is often a late symptom, indicating partial or complete compression of the spinal cord.
Examine
Examination of spinal schwannomas
Because spinal schwannomas occur mostly in the subarachnoid space, tumor growth is more likely to cause subarachnoid occlusion, so lumbar puncture and necking test, mostly manifested as subarachnoid obstruction of different degrees, due to subarachnoid obstruction, The cerebrospinal fluid circulation disorder occurs below the tumor site, and the tumor cells fall off, resulting in increased protein content of the cerebrospinal fluid. In addition, the tumor is generally free in the spinal canal, so the symptoms can be aggravated after the lumbar puncture releases the cerebrospinal fluid. This is due to the intracavitary dynamics. Learning to change the tumor caused by aggravation of the spinal cord.
Spinal plain film
Direct signs are stenotic calcifications of schwannomas, which are less common. Indirect signs refer to the corresponding changes in tumor compression of the spinal canal and its adjacent bone structure, including vertebral arch destruction, widening of the distance between the pedicles, and even vertebral arches. Root destruction disappears, vertebral body depression or intervertebral foramen enlargement.
2. Myelography
The complete obstruction rate of the subarachnoid space accounts for more than 95%, and the typical cup-shaped filling defect.
3.CT and MRI
CT scan is difficult to make a definitive diagnosis. The tumor showed an extramedullary low-signal tumor on the MRI T1-weighted image. It showed a high-signal tumor on the T2-weighted image. After enhanced imaging, the solid tumor was uniformly enhanced, and the cystic tumor was ring-shaped. Intensified, a small number of tumors showed uneven enhancement, and depending on the anatomical level of the tumor, the corresponding spinal cord shift occurred.
Diagnosis
Diagnosis and differentiation of spinal schwannomas
There is obvious radiculopathy, sports, and sensory disturbances develop from the bottom up. There is a skin allergic area at the tumor segment level, especially in the presence of spinal cord hemisection syndrome, which is expressed as the lesion segment below, ipsilateral upper motor neuron. Motor paralysis and tactile sensation, deep sensory decline, contralateral pain, loss of temperature, and changes in cerebrospinal fluid dynamics often cause pain exacerbation, suggesting the possibility of extramedullary schwannoma of the spinal cord, requiring necessary auxiliary examination to confirm the diagnosis .
For intradural tumors, the main differential diagnosis is meningioma. Meningioma often occurs in the thoracic vertebrae, but the incidence is significantly higher in women than in men. Tumors rarely grow to the nerve holes and show paravertebral masses. The tumor center is located in the nerve hole or paravertebral soft tissue lesions. The differential diagnosis should take into account ganglioneuroma, neutrophiloma, paraganglioma or local cancer and sarcoma originating from the sympathetic or dorsal root ganglia. Centripetal expansion and other lesions.
