What Is a Desmoid Tumor?

Neuroepithelial-derived tumors are collectively called gliomas, accounting for 40% to 50% of craniocerebral tumors, and are the most common primary intracranial tumors. The annual incidence is 3 to 8 people per 100,000 population.

Basic Information

English name

glioma

Visiting department

neurosurgery

Common causes

Caused by genetic and environmental carcinogens, such as electromagnetic radiation interactions

Common symptoms

It mainly depends on its occupancy effect and the function of the brain area affected, usually headache, nausea and vomiting, epilepsy, blurred vision

Causes of glioma

Like other tumors, gliomas are caused by the interaction of congenital genetic risk factors and environmental carcinogens. Some known genetic diseases, such as neurofibromatosis (type I) and tuberculosis sclerosis, are genetic susceptibility factors for gliomas. Patients with these diseases have a much higher incidence of gliomas than the general population. In addition, some environmental carcinogens may be related to the occurrence of gliomas. Studies have shown that electromagnetic radiation, such as the use of mobile phones, may be related to the generation of gliomas. However, there is no evidence to suggest that there is a necessary causal relationship between the two. Although most patients with glioblastoma have been infected with macrophage virus, and evidence of macrophage virus infection has been found in the majority of pathological specimens of glioblastoma, is there any difference between the two? The existence of causality is not yet clear.

Glioma Classification

1. Divided by the morphology of tumor cells

Gliomas are classified according to the similarity of their tumor cell morphology to normal glial cells (not necessarily their true cellular origin), as follows:

(1) Astrocytoma-Astrocytes.

(2) oligodendroblastoma-oligodendroblast.

(3) Ependymal tumor-Ependymal cells.

(4) Mixed gliomas, such as oligodendroblastic astrocytomas, contain mixed types of gliomas.

2. Divided by the degree of malignancy of tumor cells

Although there are many grading systems for gliomas, the most commonly used is the grading system developed by the World Health Organization (WHO). According to this grading system, gliomas are classified from grade 1 (with the lowest malignancy and the best prognosis) to grade 4 (with the highest malignancy and the worst prognosis). Among them, the so-called anaplastic gliomas of traditional cytopathology correspond to the level 3 of the WHO; glioblastomas correspond to the level 4 of the WHO. According to this classification system, gliomas can be further classified according to the pathological malignancy of tumor cells:

(1) Low-grade gliomas (WHO grades 1 to 2) are well - differentiated gliomas; although such tumors are not biologically benign, the prognosis of the patients is relatively good.

(2) High-grade gliomas (WHO grades 3 to 4) are poorly differentiated gliomas; such tumors are malignant tumors with poor prognosis.

3. Division by tumor location <br /> Glioma can be classified according to its location in the brain. The cerebellum divides brain tissue into supra- and sub-occipital regions. According to this, brain gliomas are also divided into supra- curtain gliomas and sub-screen gliomas.

(1) Superficial glioma is located on the cerebellum, mainly the cerebral hemisphere, and it is the most common glioma in adults (70%).

(2) Subgap glioma is located under the cerebellum, mainly in the cerebellar hemisphere, and it is the most common glioma in children (70%).

(3) The pontine glioma is located in the brain stem. The brainstem includes three parts: the mesencephalon, the pontine, and the medulla. The pontine contains vital vital functions such as breathing. Performing surgery on the pontine carries great risks.

Clinical manifestations of glioma

The symptoms and signs caused by gliomas mainly depend on their occupancy effect and the function of the brain area affected. Glioma can cause headache, nausea and vomiting, epilepsy, blurred vision and other symptoms due to its "occupying" effect in space. In addition, because of its effect on local brain tissue function, it can also cause patients to have other symptoms. For example, optic gliomas can cause vision loss in patients; spinal gliomas can cause patients with symptoms of limb pain, numbness, and weakness; gliomas in the central area can cause motor and sensory disturbances in patients; Plasma tumors can cause difficulties in patients' language expression and understanding. Because gliomas have different degrees of malignancy, they also produce symptoms at different rates. For example, patients with low-grade gliomas often have a history of several months or even the previous year, while patients with high-grade gliomas often have a history of several weeks to several months. According to the patient's medical history, symptoms and signs, the location of the lesion and the degree of malignancy can be preliminarily estimated.

Glioma test

After the patient has clinical manifestations, the most commonly performed examinations at the clinic include head CT and MRI.

Head CT

Can be initially determined whether there is intracranial space. On CT, gliomas often manifest as low-signal lesions in the brain; low-grade gliomas generally do not have peritumoral edema, and high-grade gliomas are often accompanied by peritumoral edema. In addition, CT is superior to magnetic resonance in detecting tumor bleeding and calcification. The hemorrhage caused by tumor stroke showed a high signal on CT, which indicates that the tumor is more malignant. Tumors are associated with calcification, suggesting that the pathological type of the tumor is likely to be few branches.

2. Magnetic resonance imaging (MRI)

In terms of showing the location and nature of the tumor, it is better than CT. Low-grade gliomas often show T ₁ low-signal and T ₂ high-signal intracerebral lesions on magnetic resonance, which are mainly located in the white matter, and there are often clearer boundaries on the image with surrounding brain tissue. Mild, lesions are generally not strengthened. High-grade gliomas generally have uneven signals, T ₁ low signals, and T ₂ high signals; but if there is bleeding, T ₁ sometimes has high signals; tumors often have significant uneven enhancement; tumors and surrounding brain tissue The boundaries are unclear; peritumoral edema is more severe. Sometimes, gliomas are not easily distinguished from other diseases, such as inflammation and ischemia.

3. Other

It may be necessary to do other tests, including positron emission tomography (PET), magnetic resonance spectroscopy (MRS) and other tests, to further understand the disease's glucose metabolism and other molecular metabolism, so as to distinguish between differential diagnosis. In addition, in order to clarify the relationship between the lesion and the function of the surrounding brain tissue, a so-called functional magnetic resonance examination (fMRI) is sometimes performed. Through these examinations, it is generally possible to have a preliminary clinical judgment on the location of the glioma and the level of malignancy before surgery. However, the final diagnosis depends on the pathological diagnosis after surgery.

Glioma diagnosis

For the diagnosis of glioma, the patient's medical history, symptoms, signs, auxiliary examination, and postoperative pathology must be comprehensively considered and judged.

Glioma Treatment

Surgery

Surgery is often the first step in glioma treatment. Surgery can not only provide the final pathological diagnosis, but also quickly remove most of the tumor cells, alleviate the patient's symptoms, and facilitate the next step of other treatments. For some low-grade gliomas, such as hair cell astrocytoma, a complete resection of the surgery can allow patients to get radical cure and long-term survival. The current glioma surgery has entered a minimally invasive era, which is safer, less traumatic, and more complete tumor resection than before. Microscopes are used in the resection of gliomas, which can more clearly distinguish the boundary between tumors and brain tissues, as well as surrounding important neurovascular structures, so that gliomas can be removed to the greatest extent under safe conditions. The application of neuronavigation will surgically remove glioma to a new height. Neuronavigation is similar to car navigation, which can make surgeons more accurate and detailed from the design of incisions, the identification of functional brain areas during surgery, and the choice of surgical resection methods. Intraoperative magnetic resonance, which has appeared in recent years, can further improve the completeness of complete surgical resection and reduce complications such as functional defects in patients after surgery. The application of intraoperative cortical stimulation electrodes can improve the identification of motor and language areas during surgery, thereby helping surgeons to better protect the important functions of the brain.

2. Radiotherapy

After undergoing surgical treatment, patients with high-grade gliomas often need further radiotherapy. For low-grade glioma patients, if there are high-risk factors (such as tumor volume greater than 6 cm, incomplete surgical resection, etc.), radiotherapy should also be considered. Radiotherapy includes local radiotherapy and stereotactic radiotherapy. For the first glioma, stereotactic radiotherapy is generally not used. Local radiotherapy can be divided into conformal intensity modulated radiotherapy and three-dimensional plastic radiotherapy according to different technologies. For patients with recurrent gliomas, especially tumors in the functional area, stereotactic radiotherapy can sometimes be considered.

3. chemotherapy

Chemotherapy and targeted therapy have gradually played an important role in the treatment of gliomas. For high-grade gliomas, the use of temozolomide can significantly extend the survival prognosis of patients. At present, temozolomide is the only chemotherapeutic drug with clear efficacy in the treatment of gliomas. For patients with newly diagnosed high-grade gliomas, after taking temozolomide concurrently with radiotherapy (simultaneous chemoradiotherapy), they should continue to take it alone for a period of time (6-12 cycles). Other chemotherapeutic drugs (such as nimustine) may have a certain effect on the treatment of recurrent gliomas. The newly emerged vascular targeting drug bevacizumab and Avastin has a clear effect on recurrent high-grade gliomas and can significantly prolong the survival of patients.

Glioma prognosis

After comprehensive treatment, the median survival of patients with low-grade gliomas (WHO 1 to 2) is between 8 and 10 years; the median survival of patients with anaplastic glioma (WHO 3) is 3 to 4 years The median survival of patients with glioblastoma (WHO grade 4) was between 14.6 and 17 months. It is worth noting that for patients with glioblastoma, the emergence of radiotherapy and temozolomide chemotherapy regimens can enable nearly 10% of patients to survive for more than 5 years; before the emergence of temozolomide, radiotherapy alone, only less than 1 % Of patients can survive 5 years.

Gliomas are difficult to cure and often recur. After tumor recurrence, according to the functional status of the patient, reoperation, radiation therapy, chemotherapy and other treatments can be considered.