Tumors originating from the neuroepithelium are collectively known as glioblastoma (glioblastoma), which accounts for 40-50% of cranial tumors and is the most common intracranial malignant tumor. It is the most common intracranial malignant tumor. According to the pathology, it can be divided into astrocytoma, medulloblastoma, glioblastoma multiforme, ventricular meningioma, oligodendroglioblastoma, etc.
Benign intracranial glioma is a tumor that grows in a certain part of the skull (mostly outside the neural tissue of the brain), has good cell differentiation, grows slowly, and is mostly curable. On the contrary, malignant intracranial glioma is a tumor that grows inside the nerve tissue of the brain, with poor cell differentiation and rapid growth, and is difficult to be cured. Some benign intracranial tumors, due to their deep location and many important structures around them, are already large in size when found, and cannot be removed by surgery, so their prognosis is poor. Some of the so-called intracranial malignant tumors, however, can be removed almost completely because they grow in less important brain tissues, and can survive for a long time or even be cured after surgery. There are very few brain tumors that start as benign and later turn malignant. Intracranial glioblastomas, metastases and invasive tumors are mostly malignant. Malignant glioma, also called brain cancer, is a malignant tumor that grows inside the skull.
Grading
The World Health Organization classifies gliomas into 4 grades, ranging from low to high malignancy.
Grade 1 is benign, grade 2 is low-grade malignant, and grade 3-4 is highly malignant.
WHO grade 1 glioma
(hairy cell astrocytoma): Surgery is curative. If there is residual tumor on postoperative imaging, a second surgery to remove the entire tumor is feasible. Radiotherapy and chemotherapy are extremely limited for this type of tumor.
WHO grade II glioma
(low-grade malignant glioma): Surgery is the primary treatment for tumors in non-functional areas. For patients under 40 years of age with total sarcoid resection, no additional other treatment is required. Radiotherapy should be given to patients with incompletely resected tumors under 40 years of age and to patients approximately 40 years of age with or without complete resection.
WHO grade III gliomas
(mesenchymal astrocytoma): Surgery is required to achieve a histopathologic diagnosis and to reduce the tumor size. Patients should undergo radiotherapy and chemotherapy.
WHO grade IV glioma
(glioblastoma multiforme): surgery is also required to achieve a histopathological diagnosis and to reduce the size of the tumor. Post-operative radiotherapy (at a dose of about 60Gy). Chemotherapy includes carmustine, a combination of PCV (methylbenzylhydrazine, cycloheximide and vincristine), or temozolomide for tumor growth control.
Classification
Astrocytoma
It is the most common type of glioma, accounting for about 40% of the cases. The pathological classification is grade I (astrocytoma), grade II (astroblastoma), and grade III-IV (glioblastoma multiforme). Grade I-II astrocytomas are low-grade malignant, with slow onset. The tumor is mostly solid or cystic in CT and MR, with unclear borders, and the solid part of the tumor or cystic nodules can be enhanced. Clinical manifestations vary progressively with the location of the lesion, and eventually symptoms of cranial hypertension appear. Grade III-IV glioblastoma multiforme has rapid onset and is the most malignant tumor, mostly growing in the cerebral hemispheres. The tumor may be surrounded by edema in a large area of brain tissue.
Medulloblastoma
It is a highly malignant tumor, usually found in children aged 2-10 years old, and at least in children a few months old. Most of them originate from the cerebellar earthworm and grow toward the four ventricles and the cerebellar hemisphere of the medulla oblongata.
Oligodendroglioma
Oligodendroglioma is a low-grade malignant tumor, which is benign, and many people also call it a benign tumor. It is a slow growing tumor, and calcified plaques are often seen within the tumor.
Ventricular meningioma
It is also a type of glioma and has the same principles as astrocytoma.
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, loss of vision, diplopia, and psychiatric symptoms; the other is the focal symptoms produced by tumor compression, infiltration, and destruction of brain tissue, which can manifest as irritation symptoms such as limited epilepsy in early stage and neurological deficit symptoms such as paralysis in later stage.
Embryonal tumors of the central nervous system (CNS) include malignant germ cell tumors, adult neural tube cell tumors, primitive neuroectodermal tumors (PNET), etc., which occur in children and adolescents.
Epidemiology
Brainstem tumors (brainstem gliomas) account for 1.4% of intracranial tumors. Among them, astrocytoma and polar glioblastoma are more common, followed by oligodendroglioma, ventricular meningeal glioma, medulloblastoma, and hemangioma (including vascular reticulocytoma), cyst, teratoma, tuberculoma, metastatic tumor and so on. They are more prevalent in children and adolescents, with the highest incidence especially in children aged 5-9 years. Poorly differentiated polar glioblastomas, medulloblastomas and ventricular meningiomas are more common in children, while astrocytomas are more common in adults. In children, the disease duration is short and progresses quickly; it often causes severe brainstem symptoms within a short period of time (weeks to months); in adults, the disease duration is long and progresses slowly, and severe brainstem symptoms may occur within months or even a year. The distribution of various tumors in the brainstem varies slightly, with astrocytomas located in various parts of the brainstem and medulloblastomas and ventricular meningiomas located in the perineurium of the aqueduct and the floor of the fourth ventricle.
The symptoms of brainstem tumors (brainstem glioma) can be divided into two categories: general symptoms and focal symptoms. General symptoms include posterior occipital headache. Children often have personality changes, and many patients have difficulty in urination. Increased intracranial pressure is often not the first symptom of brainstem tumors. Therefore, for progressive crossed palsy or multiple cranial nerve palsy combined with cone bundle damage, the possibility of brainstem tumor should be considered first, regardless of the presence of increased intracranial pressure. The focal symptoms of brainstem tumors vary according to the location of the tumor. Due to the infiltrative growth of the tumor, it is practically difficult to clearly delineate the specific site such as midbrain or pontine brain.
Symptoms
Brainstem tumors (brainstem glioma) symptoms.
Midbrain tumor
Symptoms of increased intracranial pressure can occur in early stages because the tumor is very likely to block the conduit. There are also first symptoms of mental and intellectual changes, which may be related to the involvement of reticular structures. Depending on the site of tumor invasion, it often manifests as: Actinic crossed hemiplegia syndrome Weber syndrome, in which the lesion is located at the base of the peduncle of the brain and presents with paralysis of the actinic nerve on the diseased side and central paralysis of the upper and lower limbs and facial and lingual muscles on the contralateral side. Parrnaud’s syndrome, a tetralogy of fallen eyelids, supraocular palsy, fixed pupils, loss of response to light, inability to converge, etc. Benedikt’s syndrome, which presents with deafness, etc., articulatory nerve palsy on the diseased side, increased muscle tone in the contralateral limb, tremor, etc.
Pontine brain tumor
Pontine brain tumors account for more than half of all brainstem tumors, mostly seen in children. More than 90% of patients have cranial nerve palsy, about 40% of patients have abducens nerve palsy as the first symptom, and with the development of tumor, cranial nerve damage such as facial nerve, trigeminal nerve and motor sensory disorders of limbs appear. Millard-Gubler syndrome, a hemiplegic damage of the pontine brain, including facial nerve cross paresis, is often manifested, and if the lesion is located in the lower part of the pontine brain on one side, it causes peripheral facial paresis with hemiplegia of the opposite limb.
Medulla oblongata tumor
The first symptom is often vomiting, which can be misdiagnosed as neurotic vomiting or neurosis, especially in adult patients. Patients may have different degrees of dizziness and headache, and then symptoms of posterior cranial nerve palsy, such as dysphagia, choking and coughing, nasal speech, inability to extend the tongue, etc., may appear earlier. If the tumor involves both sides, the patient will have true medullary paralysis syndrome, accompanied by bilateral motor and sensory impairment of the limbs and spastic paraplegia of varying degrees, and irregular breathing in the early stage of the disease, and respiratory distress or failure in the late stage.
Diagnosis
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, ultrasonic, radionuclide, radiological and magnetic resonance imaging and other auxiliary examinations.
The principle of surgical treatment is to remove the tumor as much as possible while preserving the neurological function. The principle of surgical treatment is to remove the tumor as much as possible while preserving the neurological function. Early tumors that are small and located in appropriate areas can be removed completely. For tumors located in frontal lobe, lobectomy can be performed. When the frontal or temporal lobe tumor is too extensive to be removed, the frontal pole or temporal pole can be removed for internal decompression at the same time. If the tumor is located in motor and speech area without obvious hemiparesis or aphasia, it is advisable to pay attention to preserving neurological functions and to 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 comprehensive Chinese medicine.
Characteristics of glioma and current status of treatment
The growth of glioblastoma is characterized by infiltrative growth, without obvious boundary with normal brain tissue, mostly not limited to one lobe of brain, and destroying brain tissue in a finger-like manner.
Currently, the treatment of glioma at home and abroad is generally surgery, Chinese medicine, radiotherapy, chemotherapy, X-knife, and gamma-knife.