ependymal tumor
Introduction
Introduction to ependymal tumors Ependymal cell tumors are central nervous system tumors derived from the ependymal cells of the ventricle and the central canal of the spinal cord or the white matter ependymal cells in the brain, first discovered by Virshow in 1863. According to the 1993 WHO classification of central nervous system tumors, ependymal cell tumors are divided into ependymoma, anaplastic (malignant) ependymoma, mucinous papillary ependymoma and subependymal membrane Four types of tumors. Ependymoma is low malignancy, comparable to Class I and II of Kernohan, and anaplastic ependymoma is equivalent to Kernohan III and IV. Most of the mucinous papillary ependymoma is found in the spinal tail. basic knowledge The proportion of illness: 0.002% Susceptible people: no special people Mode of infection: non-infectious Complications: cerebral edema
Cause
Ependymoma tumor etiology
Causes:
The ependymoma is mostly located in the ventricle. The main body of a few tumors is located in the brain tissue. The posterior cranial ependymoma mainly occurs in the top, bottom and side wall depressions of the fourth ventricle. Most of the tumors located in the fourth ventricle are from In the part of the medulla of the ventricle, the growth of the tumor can occupy the fourth ventricle and cause obstructive hydrocephalus. Sometimes the tumor can extend through the middle hole to the occipital pool. A few can compress or even surround the medulla or protrude into the spinal canal to compress the upper cervical spinal cord. Some tumors originate from the ventricle of the fourth ventricle, occupying the cerebellar hemisphere or the iliac crest, and occasionally the tumor occurs in the cerebellopontine angle.
On-screen tumors are more common in the lateral ventricle, which can originate from various parts of the lateral ventricle, often infiltrating into the brain parenchyma. It is rare in the third ventricle. The anterior part can extend to the bilateral ventricles through the interventricular space. The tubular tumor is considered to be the ependymal epithelium originating from the lateral ventricle or the third ventricle. The tumor can be completely in the ventricle or partially in the ventricle, partly outside the brain. However, the tumor may also occur in the cerebral hemisphere. Anywhere and completely outside the brain, the tumor originates from the ependymal cell sputum, which may be the result of malformation when folded inside the neural tube. Such tumors occur in the frontal, temporal, parietal and third ventricles.
Pathogenesis:
The study found that in ependymoma, more than 50% of the 22 chromosome fragments were lost, but the gene sequence on the missing fragments was not yet clear. Other studies have shown that monkey vacuolating virus (SV40) and ependymoma The relationship is relatively close, SV40 can express "T antigen" in infected cells. Tag can stimulate viral DNA replication by inhibiting viral DNA replication and inhibiting the function of p53 protein. Bergsagel et al. In the study of tubular tumors, 10 of the tumor cells contained SV40 gene-related sequences, and the expression of Tag was confirmed. The pathological manifestations of the tumor:
1. Ependymoma is mostly located in the ventricle, a small part can be located in the brain parenchyma and the cerebellopontine angle, the tumor is red, lobulated, texture crisp, blood supply is generally rich, the border is clear, the tumor base in the supratentorial ventricle The width is grayish red, sometimes there is cystic change. The morphology of ependymoma is not completely consistent under light microscope. The cells are moderately proliferated, the nucleus is large, round or elliptical, mitotic figures are rare, and there may be calcification or necrosis. The lower tumor section, such as the "leopard skin", is one of the diagnostic markers of ependymoma. There are two structural features of esophageal tumor under high magnification: one is the arrangement of tumor cells in the direction of the protrusion to the tumor vessel wall. The formed "fence-like" structure, called the "fake rose" nodule, is surrounded by a nuclear-free area composed of long, glial cell-like processes, and the periphery is closely surrounded by tumor nuclei; One is the so-called "true ependymal rose" nodule, which is unique to ependymoma. This structure is smaller and less common than "fake rose", but it has diagnostic value for ependymoma. "Real ependymal membrane "Rose" structure consists of a small number of morphologically uniform polygons Tumor cells into the radially arranged, forming a central lumen, immunohistochemical staining of GFAP, Valemount kiosk (Vimentin) and fibronectin (fibronectin) and the like positive.
2. The anaplastic ependymoma accounts for 45% to 47% and 15% to 17% of the supratentorial and submental ependymal cell tumors respectively. It is also called malignant ependymoma. Under the microscope, the tumor cells proliferate obviously and the morphology is diverse. The nucleus is atypical, the chromatin is abundant in the nucleus, the schizophrenia is more common, the tumor has lost the arrangement of the ependymal epithelial cells, the interstitial arrangement of the tumor is disordered, the vascular proliferation is obvious, necrosis can occur, and the variegated ependymoma is prone to appear. Tumor cell cerebrospinal fluid is disseminated and planted, the incidence rate is 8.4%, and the underlying tumor is as high as 13% to 15.7%.
3. The subependymal ependymoma is mostly located in the ventricular system, and the boundary is clear. Except in the ventricle, it can still grow in the transparent septum, the aqueduct and the central canal of the spinal cord. The tumor often has a vascular pedicle and brain stem or ventricular wall. Connected, under the light microscope, it shows tumor cell edema, which contains dense fibrous matrix and glial fiber. The tumor cell nucleus is elliptical, chromatin is dotted, and there are few mitotic figures. Some tumors may have calcification or cystic changes. There is no astrocyte in the subependymal ependymoma, which can be differentiated from the subependymal giant cell astrocytoma.
The upper cervical medulla, which originates from the top of the fourth ventricle, occupies the cerebellar hemisphere or the iliac crest, and even the tumor appears in the cerebellopontine angle.
On-screen tumors are more common in the lateral ventricle, which can originate from various parts of the lateral ventricle, often infiltrating into the brain parenchyma. It is rare in the third ventricle. The anterior part can extend to the bilateral ventricles through the interventricular space. The tubular tumor is considered to be the ependymal epithelium originating from the lateral ventricle or the third ventricle. The tumor can be completely in the ventricle or partially in the ventricle, partly outside the brain. However, the tumor may also occur in the cerebral hemisphere. Anywhere and completely outside the brain, the tumor originates from the ependymal cell sputum, which may be the result of malformation when folded inside the neural tube. Such tumors occur in the frontal, temporal, parietal and third ventricles.
Prevention
Ependymoma prevention
Prevention: There are currently no effective preventive measures.
Complication
Ependymologic tumor complications Complications brain edema
If surgery is performed, the following complications may occur:
1. Intracranial hemorrhage or hematoma: It is not related to intraoperative hemostasis. With the improvement of surgical techniques, this complication has been less frequent. The wound is carefully hemostasis and repeated flushing before closing the skull can reduce or avoid postoperative intracranial hemorrhage.
2. Brain edema and postoperative high intracranial pressure: decompressive drugs can be used to reduce intracranial pressure, glucocorticoids reduce brain edema.
3. Loss of nerve function: related to the important functional area and important structure of intraoperative injury, avoiding damage as much as possible during surgery, and symptomatic treatment after emergence.
Symptom
Ependymoma symptoms common symptoms gait instability low fever diplopia sensory disorder drowsiness dyspnea coma eyeball tremor visual impairment
1. The performance of different types of tumors:
Patients with under-the-sector ependymoma have a longer course of disease, with an average of 10 to 14 months. The under-the-sector ependymoma mainly presents with paroxysmal nausea, vomiting (60%-80%) and headache (60%-70%), which may appear later. Unstable walking (30% to 60%), dizziness (13%) and speech disorder (10%), signs mainly cerebellar ataxia (70%), optic disc edema (72%), cranial nerve disorder (20%) 36%) and sputum reflex abnormality (23%), the most common symptom of fourth ventricular ependymoma is gait abnormality, supratentorial ependymoma with headache, vomiting, lethargy, anorexia and diplopia Mainly (67% to 100%), and may have seizures (25% to 40%), ependymoma located in the cerebellopontine angle of the cerebellum may have tinnitus, deafness and posterior group cranial nerve symptoms, symptoms of children under 2 years old Special, mainly for irritability, lethargy, loss of appetite, enlarged head circumference, full front sputum, stiff neck, stunting and weight loss.
The anaplastic ependymoma has a relatively rapid tumor growth, and the patient has a short course of disease. The symptoms of the cranial hypertension are obvious. About 40% of the patients with subependymal ependymoma have symptoms. The tumor is located in the transparent septum, Monro hole, water conduit, and fourth. The ventricles and spinal cord often cause symptoms. The patients are mainly characterized by headache, blurred vision, unstable walking, memory loss, cranial nerve symptoms, nystagmus, dizziness and nausea, vomiting, and 88% of patients have hydrocephalus.
2. The performance of different parts of the tumor:
Due to the different parts of the tumor, the clinical symptoms of patients with ependymoma are very different. The nausea, vomiting and headache are relatively non-specific, and are the most common clinical symptoms on the screen and under the curtain. Generally speaking, after Craniofacial tumors showed symptoms of increased intracranial pressure (vomiting and headache) accompanied by gait instability; on-screen tumors showed local motor dysfunction, visual impairment and epilepsy, and epileptic symptoms accounted for the supratentorial chamber 25% of children with membranous tumors, neck pain, and stiffness are common symptoms of posterior cranial ependymoma, which may be related to tumor invasion of the cervical nerve root.
The most common signs in children with ependymoma at any site are optic disc edema, other signs vary according to the location of the tumor, nystagmus, meningeal signs and poor range are most common in posterior fossa lesions, while hemiplegia, tendon reflexes Hyperthyroidism and visual field abnormalities are the most common signs of on-screen tumors, and ataxia is seen in both on- and off-screen lesions.
Before the diagnosis, the duration of symptoms is 1.5 to 36 months. Most patients have a disease duration of about 12 months. The length of the disease varies according to the location and grade of the tumor. The average duration of on-screen tumors is 7 months (2 weeks~ 3 years), and the average course of posterior cranial ependymoma is 9 months (2 weeks to 2 years). In general, benign lesions have a longer course than malignant lesions, and posterior cranial fossa that invades surrounding structures. Esophageal tumors require symptoms for 5.4 months, while tumors that are largely non-invasive require symptoms for 11 months; supratentorial ependymoma with calcification has a longer duration of symptoms than non-calcified tumors, but posterior cranial fossa There were no significant differences in the duration of symptoms in patients with ependymoma who showed calcification and no calcification.
(1) Fourth ventricle ependymoma: Because the tumor is located in the ventricle, it is easy to block the cerebrospinal fluid circulation pathway, and the symptoms of increased intracranial pressure often appear in the early stage. When the tumor oppresses the cerebral nucleus at the bottom of the fourth ventricle or oppresses the cerebellum to the lateral side When the foot is used, it can cause cranial nerve damage and cerebellar symptoms in the clinic.
1 symptoms of increased intracranial pressure: it is characterized by intermittent, related to head position changes, often in the advanced stage of forced head, head flexion or anterior flexion, due to position changes can stimulate the nerve nucleus at the bottom of the fourth ventricle, especially It is the vagus nerve and vestibular nuclei, which are characterized by severe headache, dizziness, vomiting, pulse, respiratory changes, sudden loss of consciousness, and diplopia, nystagmus, etc. due to the affected nerve nuclei, called Brun sign, due to tumor Activity, can suddenly block the median hole or the water tube caused by cerebrospinal fluid circulation, so it can be increased intracranial pressure, this phenomenon occurs mostly due to sudden changes in body position, severe cranial pressure can occur cerebellar crisis.
2 brainstem symptoms and symptoms of cranial nerve damage: less brain stem symptoms, when the tumor is compressed or infiltrated into the bottom of the fourth ventricle, there may be symptoms of pons and medullary nucleus involvement, mostly after increased intracranial pressure, a few There are also symptoms of cranial nerves as the first symptom, and the symptoms of cranial nerve damage appear. The process and extent of involvement are closely related to the location and extension direction of the tumor. The tumor affects the V, VI, VII, VIII brain in the upper part of the fourth ventricle. The nucleus, which affects the medial longitudinal bundle along the midline, can cause the eyeball to gaze to the affected side, and can also produce eye movement deflection. The tumor in the lower part of the fourth ventricle mainly affects the IX, X, XI, XII cerebral nucleus. Often vomiting, hiccups as the first symptom, followed by dysphagia, hoarseness and visceral symptoms due to vagus nerve stimulation, sometimes even sphincter dysfunction and dyspnea; tumors starting in the fourth ventricle crypt, Often to the ipsilateral cerebral cerebellopontine angle development, with V, VII, VIII cranial nerve involvement, mainly manifested as facial and facial dysfunction, hearing and Symptoms of vestibular dysfunction and dizziness, when the brain stem long-conducting beam is involved, most of them are caused by tumor or chronic occipital foramen magnum. The brain may be weak, the tendon reflex is low or disappear, and the pathological reflex is often bilateral. The ependymoma of the fourth ventricle often develops to the upper cervical spinal cord through the occipital macropores, and the lowest can reach the level of the neck 2 to 3, sometimes it can be wound around the cervical spinal cord for a week, which is characterized by neck pain, stiffness, and more after occurrence. Group of cranial nerve palsy.
3 cerebellar symptoms: cerebellar symptoms are generally mild, because the growth of the tumor along the lateral or dorsal side affects the cerebellum or cerebellar ventral side, manifested as unstable walking, often seen nystagmus, some patients show ataxia and muscle strength Decrease.
(2) lateral ventricle ependymoma: lateral ventricle ependymoma from the lateral ventricle wall, the lateral ventricle frontal angle and body are more common, the tumor grows slowly, can grow very large and fill all the lateral ventricle, a few tumors The body can be drilled into the third ventricle through the interventricular hole. The symptoms of the lateral ventricle tumor are as follows:
1 symptoms of increased intracranial pressure: because the tumor grows slowly, the symptoms are not obvious before the cerebrospinal fluid circulation disorder, because the tumor has a certain degree of activity in the ventricle, it can produce seizure headache with vomiting with the change of body position. Heavy, not easy to be detected, patients often keep their heads in a certain position (ie, forcing the head position), when the tumor volume increases enough to cause cerebrospinal fluid circulation is blocked, only a series of intracranial headaches such as persistent headache, vomiting, optic disc edema Symptoms of increased pressure, rapid increase in intracranial pressure can cause coma or death, and children with enlarged intracranial pressure can increase head and vision loss.
2 local symptoms of the tumor: early due to the tumor on the brain tissue compression is relatively mild, local symptoms are not obvious, when the tumor grows large, especially when the invasion of the thalamus, the internal capsule and basal ganglia or tumor invasion into the brain parenchyma, can be expressed Side hemiparesis, unilateral sensory disturbances and central facial paralysis, tumors caused by epilepsy are rare.
(3) Third ventricle ependymoma:
The third ventricle ependymoma is extremely rare, and the tumor is located in the posterior part of the third ventricle. Because the third ventricle is narrow, it is easy to block the cerebrospinal fluid circulation pathway and cause obstructive hydrocephalus. Early intracranial pressure is increased and progressive. Exacerbation, sometimes due to the flap of the tumor to block the interventricular pores and the upper mouth of the water tube, there are symptoms such as episodic headache and vomiting, and may be accompanied by low fever. In the front of the third ventricle, optic nerve compression symptoms and pituitary gland may occur. Thalamic symptoms, located in the posterior part of the third ventricle may appear symptoms such as ocular dyskinesia.
(4) Ependymoma in the brain:
Some ependymoma do not grow in the cerebral parenchyma and are located in the brain parenchyma. The tissue is derived from the ectopic ependymal cells of the embryo. It may also be that the tumor originating from the ventricular wall grows into the brain parenchyma. In the frontal and parietal lobe, the tumor is often located in the deep cerebral ventricle of the brain, and is also exposed on the surface of the brain. The clinical manifestations are similar to the symptoms of various parts of the brain. It is common in smaller children, and the tumor is huge. It is difficult to diagnose before surgery.
Examine
Ependymoma examination
In most patients, the lumbar puncture pressure is increased, especially in the case of under-the-slice tumors with hydrocephalus. About half of the patients have increased cerebrospinal fluid protein. About one-fifth of the patients have increased cerebrospinal fluid cells, because tumor cells often fall off the cerebrospinal fluid. Therefore, it is necessary to pay attention to the identification of white blood cells when examining cerebrospinal fluid.
Skull CT and MRI have diagnostic value for ependymoma. The tumor has a slightly high-density shadow on the CT scan. The inclusion of low density and high density calcification in the tumor (Fig. 1), supratentorial tumor Calcification and cystic changes are more common in the underlying tumors. Some of the supratentorial tumors are located in the brain parenchyma, and the surrounding brain tissue is mild to moderate edema. On MRI, the T1 weight is low, and the signal amplitude is high. The proton weighting and T2 weighting are high. Signal, after the injection of the enhancer, the tumor showed a moderate to significant enhancement, and some were irregular enhancement (Figure 2).
The anaplastic ependymoma is enhanced on CT and MRI. The tumor MRI shows a low signal of T1W, a high signal on T2W and proton-weighted images, and a heterogeneous signal in the tumor, which may have necrotic cystic changes (Fig. 3).
Subependymal ependymoma appears on CT as a tumor image with a clear or low-density boundary located in the ventricle (Fig. 4). On MRI, the tumor exhibits a low T1W signal, and T2W and proton-weighted high-signal images ( Figure 5), about half of the tumor signals are not uniform, caused by calcification or cystic changes, and some tumors may have uneven enhancement after injection of the enhancer.
Diagnosis
Diagnosis and diagnosis of ependymoma
Diagnosis can generally be made based on clinical manifestations and auxiliary examinations.
