Glioma, referred to as glioma, is a tumor that occurs in the neuroectoderm. There are two types of tumors occurring in the neuroectoderm: those formed by mesenchymal cells, called gliomas, and those formed by parenchymal cells, called neuronal tumors. Since these two types of tumors cannot be completely distinguished from each other in terms of pathogenesis and morphology, and gliomas that originate from mesenchymal cells are much more common than neuronal tumors that originate from parenchymal cells, neuronal tumors are included in gliomas and are collectively referred to as gliomas. There are many ways to classify gliomas, but clinical workers often use the Kernohan classification, which is relatively simple. Among the various types of gliomas, astrocytomas are the most common, followed by glioblastomas, followed by medulloblastomas, ventricular meningiomas, oligodendrogliomas, pineal tumors, mixed gliomas, choroid plexus papillomas, unclassified gliomas, and neuronal tumors. For example, astrocytomas are more common in the cerebral hemisphere in adults and in the cerebellum in children; glioblastomas almost always occur in the cerebral hemisphere; medulloblastomas occur in the cerebellar earth; ventricular meningiomas are more common in the 4th ventricle; and oligodendrogliomas occur mostly in the cerebral hemisphere. Gliomas are more common in males, especially in glioblastoma multiforme and medulloblastoma, which are significantly more common in males than females. Glioblastomas of all types are more common in middle age, ventricular meningiomas are more common in children and young adults, and medulloblastomas almost always occur in children. The location of gliomas is also related to age, for example, astrocytomas and glioblastomas of the brain are most often seen in adults, and gliomas of the cerebellum (astrocytomas, medulloblastomas, and ventricular meningiomas) are most often seen in children. Most gliomas develop slowly, with the time from the onset of symptoms to the time of consultation usually ranging from a few weeks to a few months, and rarely up to several years. The history is shorter for highly malignant and posterior cranial fossa tumors and longer for tumors that are more benign or located in the quiet zone. If a tumor has hemorrhage or cystic changes, the symptoms may suddenly worsen and even have a course similar to cerebrovascular disease. The clinical symptoms of glioma can be divided into two aspects: one is the symptoms of increased intracranial pressure, such as headache, vomiting, vision loss, diplopia and psychiatric symptoms; the other is the focal symptoms produced by tumor compression, infiltration and destruction of brain tissues, which can manifest as irritation symptoms such as limited epilepsy in the early stage and neurological deficit symptoms such as paralysis in the later stage. The diagnosis of glioma is based on its biological characteristics, age, gender, predilection site and clinical course. Based on the medical history and signs, the correct localization rate is almost 100% and the correct qualitative diagnosis rate can be more than 90% by using electrophysiological, ultrasound, radionuclide, radiological and magnetic resonance imaging and other auxiliary examinations. The treatment of glioma is mainly surgical. Since the tumor grows infiltratively and has no clear demarcation with brain tissue, it is difficult to completely remove it, and postoperative radiotherapy, chemotherapy and immunotherapy are extremely necessary. The principle of surgical treatment is to remove the tumor as much as possible while preserving the neurological function. If the tumor is small in early stage and located in appropriate area, we can try to remove all of it. For tumors located in frontal or temporal lobe, lobectomy can be performed. When the frontal or temporal lobe tumor is too extensive to be removed, the frontal or temporal pole can be removed at the same time for internal decompression. If the tumor is located in motor and speech area without obvious hemiparesis or aphasia, it is advisable to pay attention to preserve neurological function and remove the tumor appropriately to avoid serious sequelae. For ventricular tumors, it is advisable to cut the brain tissue from non-functional areas to enter the ventricles, remove the tumor as much as possible and release the brain obstruction. For gliomas located in the thalamus and brainstem, except for small nodular or cystic ones, they can be resected and generally shunted to relieve the increased intracranial pressure and then treated with radiation therapy and other comprehensive treatments. Radiation therapy is recommended as soon as possible after the recovery of general condition after surgery. Chemotherapy for glioma tumors tends to be combined with several drugs to improve the efficacy according to the cell kinetics and the specificity of the drugs to the cell cycle. For example, nitrosoureas are used in combination with VCR and PCB, or with VM26, ADM, methotrexate (MTX), bleomycin (BLM), etc. In order to increase local drug concentration and reduce systemic toxicity, special routes of drug delivery can also be used, such as local injection of ADM and MTX through Ommaya reservoir, and injection of cancer drugs through selective catheters from the arteries supplying blood to the tumor. Immunotherapy for glioma, including active immunization with tumor vaccine, intra-lymph node injection of immune ribonucleic acid and application of immunomodulators such as levamisole, PSK, PSP, etc. are also used clinically to reduce the response to radiotherapy and chemotherapy and enhance immunity. For glioma inhibition therapy, bufotanine is the most ideal gene expression-based drug for glioma inhibition therapy. Diagnosis of glioma is based on age, sex, site of occurrence and clinical course, and estimation of the pathological type. In addition to the medical history and neurological examination, some auxiliary examinations are also needed to help diagnose the localization and characterization. Cerebrospinal fluid examination: the pressure of lumbar puncture is mostly increased, some tumors located on the brain surface or intracerebral ventricle may increase the amount of cerebrospinal fluid protein, the number of white blood cells may also increase, and some tumor cells may be detected. However, if the intracranial pressure is significantly increased, lumbar puncture may promote the risk of brain herniation. Therefore, it is usually done only when necessary and when it is necessary to differentiate from inflammation or hemorrhage. In cases of significant pressure increase, the operation should be performed with caution and not to release more cerebrospinal fluid. Give mannitol drip after the operation and pay attention to observation. 2.Ultrasonic examination: it can help to fix the side and observe whether there is hydrocephalus. For infants, B-type ultrasound scan can be performed through fontanel, which can show tumor images and other pathological changes. 3.Electroencephalography: The EEG changes of glioma are, on the one hand, the changes of brain waves confined to the tumor site. On the other hand, they are general widely distributed changes of frequency and wave amplitude. These are influenced by tumor size, infiltration, degree of cerebral edema and increased intracranial pressure, etc. Superficial in tumors are prone to limited abnormalities, while deeper tumors are less likely to have limited changes. In the more benign astrocytomas and oligodendrogliomas, they mainly present as limited delta waves, with some visible epileptic waveforms such as spikes or sharp waves. Large glioblastoma multiforme may show widespread δ waves, sometimes only fixed laterally. 4. Radioisotope scan (Y-ray brain map): Tumors with fast growth and rich blood flow have high blood-brain barrier permeability and high isotope uptake rate. For example, glioblastoma multiforme shows isotope concentrated image, and there may be low density area formed by necrosis and cyst in the middle, which should be differentiated from metastases according to its shape and multiplicity. Astrocytomas and other benign gliomas have lower concentrations, often slightly higher than the surrounding brain tissue, and the images are less clear, and some may be negative. 5.Radiological examination: including cranial plain film, ventriculography and computed tomography scan. Cranial plain film can show intracranial pressure increase, tumor calcification and pineal gland calcification displacement, etc. Ventriculography can show cerebral vascular displacement and tumor vascular condition. These abnormal changes, which vary in different types of tumors in different locations, can help localize and sometimes even characterize the tumor. Especially, CT scan has the greatest diagnostic value. Intravenous contrast-enhanced scan has almost 100% accuracy of localization and more than 90% correct rate of qualitative diagnosis. It can show the site, scope, shape, brain tissue reaction and ventricular compression displacement of the tumor. However, it still needs to be combined with clinical consideration in order to make a clear diagnosis. MRI: The diagnosis of brain tumor is more accurate than CT, and the image is clearer, and it can find tiny tumors that cannot be shown by CT. Positron emission tomography can obtain images similar to CT, and can observe the growth and metabolism of tumors and identify benign malignant tumors. The course of glioma varies depending on the type of pathology and location. The time from the appearance of symptoms to the time of consultation usually ranges from weeks to months, with a few cases lasting several years. The history is shorter for highly malignant and posterior cranial fossa tumors and longer for more benign tumors or tumors located in the so-called quiet zone. If the tumor has hemorrhage or cyst formation, the progression of symptoms may be accelerated, and some may even resemble the progression of cerebrovascular disease. The symptoms are mainly manifested in two aspects. One is the increase of intracranial pressure and other general symptoms, such as headache, vomiting, loss of vision, diplopia, seizures and psychiatric symptoms. The other is the local symptoms produced by the compression, infiltration and destruction of brain tissue by tumor, resulting in neurological deficits. Headache is mostly caused by the increase of intracranial pressure. The growth of tumor gradually increases the intracranial pressure, which compresses and involves pain-sensitive structures in the skull such as blood vessels, dura mater and certain cranial nerves and produces headache. Most of the headaches are throbbing and swelling pains, mostly in the frontotemporal or occipital area. For tumors in the superficial hemisphere of one side of the brain, the headache may be mainly on the affected side. Vomiting is caused by stimulation of the medullary vomiting center or vagus nerve, and may be jet-like without nausea. In children, the headache is not significant due to the separation of cranial suture, and vomiting is more prominent because tumor in posterior cranial fossa is common. Increased intracranial pressure may produce optic papillar edema and cause secondary optic nerve atrophy and vision loss. If the tumor compresses the optic nerve, primary optic nerve atrophy will occur, which also leads to vision loss. Adductor nerve is easily squeezed and pulled, which often leads to paralysis and diplopia. Some patients with tumors have seizure symptoms, which can be early. The epilepsy begins in adulthood and is usually symptomatic, mostly due to brain tumors. The presence of a brain tumor should be considered in all cases where the seizures are not easily controlled by medication or have a change in nature. Tumors adjacent to the cortex are prone to epilepsy, while those deeper in are less common. Focal epilepsy has localization implications. Some tumors, especially those located in the frontal lobe, may gradually develop psychiatric symptoms, such as personality changes, apathy, decreased speech and activity, inattention, memory loss, lack of concern for things, and lack of awareness of neatness. The local symptoms will be aggravated progressively depending on the location of the tumor. In particular, malignant glioma grows faster, infiltrates and destroys brain tissues, and the surrounding brain edema is also significant, so the local symptoms are more obvious and develop faster. Tumors in the intracerebroventricular region or tumors located in the quiet zone may have no local symptoms in the early stage. In contrast, tumors in the brainstem and other important functional areas show local symptoms at early stage, and it takes a long time before the symptoms of increased intracranial pressure appear. For some tumors that develop slowly, the symptoms of increased intracranial pressure often appear only at a late stage due to compensatory effects. The pathogenesis of glioma is due to the gradual enlargement of the tumor, forming intracranial occupying lesions and often accompanied by peripheral cerebral edema, when the compensatory limit is exceeded, intracranial pressure will be increased. When the tumor obstructs the cerebrospinal fluid circulation or compresses the vein, which leads to the obstruction of venous return, the intracranial pressure increases even more. If hemorrhage, necrosis and cyst formation occur in the tumor, the process can be accelerated. When the increase of intracranial pressure reaches the critical point, the intracranial volume continues to have a small increase and the intracranial pressure will increase rapidly. If intracranial pressure monitoring is performed, when the pressure reaches 6.67~13.3kPa Hg, plateau wave will appear, and the plateau wave will appear repeatedly and last for a long time, which is the clinical sign. When the intracranial pressure equals to arterial pressure, cerebrovascular paralysis, cerebral blood flow stops, blood pressure drops, and the patient will die soon. When the tumor increases, the local intracranial pressure will be the highest and the pressure gradient between the intracranial compartments will cause brain displacement, which will lead to brain herniation if it is gradually aggravated. Tumors in the supratentorial cerebral hemisphere can produce subfalx herniation and cingulate gyrus shift across the midline, which can cause wedge-shaped necrosis. The pericallosal artery may also be displaced by pressure, and cerebral infarction may occur in the supply area in severe cases. More importantly, the medial temporal lobe gyrus herniates through the cerebellar tract to the posterior cranial fossa. The ipsilateral arteriolar nerve is paralyzed by compression, the pupil is dilated, and the light response is lost. Compression of the cerebral peduncle of the midbrain produces contralateral hemiparesis. Sometimes the contralateral cerebral peduncle is compressed on the edge of the cerebellar curtain or the tip of the bone, producing ipsilateral hemiparesis. The posterior choroidal artery and posterior cerebral artery may also be compressed, causing ischemic necrosis. Finally, compression of the brainstem may produce downward axial displacement, leading to infarct hemorrhage in the midbrain and upper pontine brain. The patient becomes comatose, blood pressure rises, pulse is slow, breathing is deep and irregular, and decerebrate brain tonicity may occur. Eventually death occurs with respiratory arrest, decreased blood pressure, and cardiac arrest. Inferior posterior cranial fossa tumor may produce herniation of the greater occipital foramen and downward displacement of the cerebellar tonsils herniating out of the greater occipital foramen. In severe cases, the medulla oblongata ventrally compresses the anterior border of the foramen magnum. Supratentorial tumors may also herniate the foramen magnum. The patient becomes unconscious, blood pressure rises, pulse is slow and strong, and breathing is deep and unplanned. Subsequently, the patient stops breathing, blood pressure drops, pulse is rapid and weak, and death occurs. Epidemiology of gliomas Gliomas are the most common of all intracranial tumors. Among the gliomas, astrocytoma is the most common, followed by glioblastoma multiforme, and ventricular meningioma takes the third place. According to the statistics of Beijing Xuanwu Hospital and Tianjin Medical College Hospital, among 2573 cases of glioma, 39.1%, 25.8% and 18.2% respectively. The gender is more common in men, especially in glioblastoma multiforme and medulloblastoma, which are significantly more common in men than women. Age is mostly between 20 and 50 years old, with a peak at 30-40 years old, and another small peak in children around 10 years old. Each type of glioma has its own age of predilection, for example, astrocytoma is most common in the prime of life, glioblastoma multiforme is most common in middle age, ventricular meningioma is most common in children and young adults, and medulloblastoma is most common in children. The preferential sites of each type of glioma are also different, for example, astrocytomas occur mostly in the cerebral hemisphere in adults and in the cerebellum in children; glioblastoma multiforme almost always occurs in the cerebral hemisphere; ventricular meningioma mostly occurs in the fourth ventricle; oligodendroglioma mostly occurs in the cerebral hemisphere and medulloblastoma almost always occurs in the cerebellar earth.