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Gliomas and metastases constitute the majority of malignant tumors of the brain. 



Gliomas are a type of tumor that starts in the brain and spinal cord. It is called glioma because it originates from support cells called glial cells found in the central nervous system. Although it is more common in the brain, it can also be seen in the cerebellum and spinal cord. It is possible to classify gliomas according to cell type, histological features, grade and localization.


Gliomas arise from certain cell groups histologically. The main glioma cell types are:

     - Ependymomas – They originate from Ependymal Cells_cc-581904_bbd5cf3c

     - Astrocytomas – They originate from cells called astrocytes, the most common glioblastoma

     - Oligodendrogliomas – Originate from Oligodendrocytes-Oligodendrocytes-cc3b-cc3351994_

     - Mixed giomas– These are astroglial tumors of several different glial cells, such as astroglial tumors.


Gliomas are categorized according to their grade, in this way, information about the pathological behavior of the tumor is obtained.

  • Low Grade Tumors (World Health Organization WHO grade II) although these tumors are not benign, they have a good prognosis

  • High Grade Tumors: (WHO Grade III-IV) these gliomas are those that are not well differentiated or anaplastic. These tumors are malignant and have a poor prognosis. 

The most commonly used grading system is the WHO system, and tumors are graded from grade I (with the best prognosis) to Grade IV (with the worst prognosis).


Gliomas are named according to whether they are under (cerebellum side) or above (cerebrum side) membrane separating both structures called tentorium between cerebrum and cerebellum.

  • Supratentorial: they are located in the cerebrum above the tentorium, mostly seen in adults (70%)

  • Infratentorial: they are located in the cerebellum below the tentorium and are mostly seen in children (70%)

  • Pontine: located in the pons of the brain stem: ponsun  has vital functions


Gliomas are rarely completely cured. The prognosis in high-grade gliomas is generally poor, especially in the elderly. When we adapt the general international data to the Turkish population, an average of 2000 – 2500  malignant glioma cases are diagnosed annually. Half of these patients survive for more than one year and 25% for more than two years. The average life expectancy in anaplastic astrocytomas is about three years. The median survival of glioblastomas is 12 months, with recent treatments increasing to 14 months, and survival rates above 5 years have increased statistically significantly with recent treatments. The prognosis is definitely better for low-grade tumors. In one study, the average life expectancy in patients with low-grade oligodendroglioma was 11.6 months, while in another study it was 16.7 years.














     Metastases of the Brain

Brain metastases constitute more than half of clinically seen brain tumors. In the USA, there is an annual incidence of 17,000 primary brain tumor cases compared to 100,000 new meth cases. Brain metastases are found in 15-30% of cancers. Metastasis is the first finding in 15% of patients without a history of cancer. Abnormal chest X-ray is seen in 43-60% of these patients (showing a primary lung or tumor that has also invaded the lung). The only area of metastasis that can be found in 9% of patients is the brain. Brain metastases are seen in 6% of children. Although the form of brain metastasis is often by blood, it can sometimes be seen in local spread.


Reasons for the increase in the incidence of brain metastases:

     - Increase in life expectancy in cancer patients as a result of the application of good treatment methods._cc-581905-bbcbad53c

     - Prevalence in the use of CT and MRI._cc781905-5cbcde-3194-

     - This is a "heaven" for tumors, since many drug treatments used cannot cross the blood and brain barrier. 5cde-3194-bb3b-136bad5cf58d_

     - Some drug treatments can weaken the blood and brain barrier and facilitate spread to the brain.

Signs and symptoms:

Symptoms depend on which part of the central nervous system the disease affects. Brain gliomas present with headache, nausea, vomiting, seizures and cranial nerve involvement. Here, it should be well known that especially high-grade tumors such as glioblastoma may cause advanced edema and may give signs of increased intracranial pressure. It is manifested by loss of vision in some localized tumors such as optic glioma. Gliomas in the spinal cord present with pain, numbness and weakness in the extremities. Gliomas do not spread through the blood and metastasize, but they can spread to the spinal cord called drop metastases by spreading with the Cerebrospinal Fluid (CSF) (especially ependymomas). 
In children, especially with subacute disease accompanied by lower cranial nerve paralysis, long tract findings (first motor neuron findings) should make us think of pontine gliomas.


Although the treatment in brain gliomas may vary depending on the location of the tumor and the degree of malignancy, a combined treatment approach is often used. The most important pillar of the treatment is surgery and the degree of surgery. Surgery causes both pathological diagnosis and reduction in the number of cancer cells and increases the effectiveness of subsequent treatments. Other treatments are radiotherapy and chemotherapy. Radiotherapy applied in these tumors is usually in the form of external beam radiotherapy. In rare cases, stereotaxic radiosurgery (Gamma knife, etc.) is applied in small recurrences or residues. Temazolomide, a recently applied chemotherapeutic agent, is effective by crossing the blood-brain barrier.

Microsurgical principles have become standard in neurosurgery and similar procedures are applied in tumor surgery. In recurrent surgeries, one should be more aggressive and try to remove most of the tumor. (≥ 98%) In some patients, where sensitive areas do not constitute a contraindication for surgery, intraoperative imaging techniques such as intraoperative MRI and/or ultrasound and tumor removal with fluorescent light microscopes can be used as an adjunct if necessary. A biopsy can be performed to rule out radio-necrosis in multicentre, deeply located, or surgically inaccessible tumors. Routine repetitive biopsies have not been shown to be beneficial in oncologic decision making.

Even with optimal treatment for metastases, the survival of patients with brain metastases is still between 26-32 weeks, so palliative treatments constitute the majority of treatments.

It should be noted that 11% of patients with cancer in their history (within the past five years) do not have brain metastases in their CT and MRI scans. In differential diagnosis; Glioblastoma, low-grade astrocytoma, abscess and non-specific inflammatory reaction should be kept in mind. For this reason, it would be appropriate to administer chemotherapy and radiotherapy after the pathological diagnosis of the patient is made by surgical biopsy or open surgery.

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