A glioma is a type of brain tumor that forms from supporting cells of the nerve tissue (glial cells). Depending on which type of glial cells the tumor results in, one distinguishes between different types of tumors such as astrocytoma, glioblastoma and mixed tumors. Therapy options include surgery, radiation and chemotherapy. The prognosis varies – some gliomas are curable, others are not. Here you read everything important about the disease.
Glioma: General
Glioma is an umbrella term for various brain tumors, which develop from supporting tissue of the nervous system (glial cells). Every year about 50 to 60 out of every 1 million people get glioma. This is the most common malignant brain tumor. Some types of glioma can occur as early as childhood, while others develop in adulthood.
Glioma: WHO grade
The World Health Organization (WHO) divides gliomas into WHO grade just like other brain tumors, depending on how well or malignant they are. The classification ranges from grade I (easy to treat, favorable prognosis) to grade IV (fast-growing malignant tumor, not curable). It affects the treatment and gives an indication of the probable course of the disease.
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WHO grade |
glioma |
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I |
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II |
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III |
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IV |
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Glioblastoma is by far the most common. This is followed by the various astrocytomas. The rarest is the oligodendroglioma.
Low grade WHO gliomas can become a high grade variant. Therefore, the average age of onset increases with the WHO degree.
The different types of glioma
A glial cell tumor can form at different sites in the central nervous system. He can then be classified according to its location, for example, in a Optikusgliom (optic nerve) or a Ponsgliom (on the brainstem).
Another possibility of classification is based on which type of glial cells the tumor develops. Thus one differentiates for example:
astrocytoma
An astrocytoma forms from so-called astrocytes. These cells make up the largest proportion of the supporting cells (glial cells) in the central nervous system. They separate the nerve tissue from the brain surface and the blood vessels. There are several astrocytomas classified in WHO grades I to III. Second- and third-degree astrocytomas can pass into glioblastoma (grade IV).
astrocytoma
Further information about astrocytoma can be found in the article Astrocytoma.
Glioblastoma (astrocytoma grade IV)
Glioblastoma is a very aggressive, malignant brain tumor with WHO grade IV. Its cells of origin are astrocytes. A primary glioblastoma arises directly from healthy astrocytes. In contrast, the secondary glioblastoma develops from an already existing tumor (such as grade II astrocytoma).
glioblastoma
Read more about this dangerous brain tumor in the article Glioblastoma.
oligodendroglioma
An oligodendroglioma forms from so-called oligodendrocytes, another type of glial cells. Like an insulating layer, they encase individual nerve tracts in the brain and thereby accelerate the flow of information. Like all cells in the body, the oligodendrocytes are renewed from time to time. If errors occur, the cells can begin to multiply uncontrollably and form a tumor.
In brain imaging, oligodendrogliomas often show calcified structures. They are in WHO grades II and III and have a much better prognosis than astrocytomas of the same WHO grade. In addition, they can be better treated by chemotherapy or radiotherapy. An oligodendroglioma can pass into a secondary glioblastoma.
ganglioglioma
This type of tumor is formed from largely mature ganglion cells and Schwann cells. Ganglia are nerve nodes in which various information is interconnected. Schwann cells are a type of glial cells. They encase peripheral nerve fibers and are a counterpart to the oligodendrocytes in the central nervous system (brain and spinal cord).
A ganglioglioma can arise in principle in the entire nervous system, but is often found in the temporal lobe, cerebellum or hypothalamus. It is usually a slow-growing, benign tumor that is most common in children and young adults. Overall, this tumor is very rare.
Gliomatosis cerebri
The term gliomatosis cerebri is used by physicians when there are diffuse tumors in at least three brain lobes and a glioma has been detected in a tissue sample. Although the individual tumor foci may belong to different WHO grades, gliomatosis cerebri is assigned to WHO grade II. The course of the disease depends on the number and type of affected brain regions and varies greatly. Due to the extensive infestation, surgery is usually not possible. Irradiation would also involve a very large irradiation field and is therefore unfavorable. Treatment therefore usually consists of chemotherapy.
Glioma: diagnosis and therapy
The basic diagnostics and the usual therapy procedures for a glioma correspond essentially to those of other brain tumors. But there are some peculiarities, such as tumor detection:
A glioma consists of glial fibers, which can be detected in a tissue sample. For this, the glial fiber protein (GFAP) or the protein 100 are marked in color. Thus, a distinction to other tumors in the brain is possible because they do not contain the said proteins.
Diagnosis and therapy
Further information on the usual diagnostic and therapeutic procedures can be found in the article Brain Tumor.
Glioma: prognosis
In addition to the WHO degree classification, the age and general condition of the patient also influence the prognosis of the disease. The older and sicker one gliomaPatient is at diagnosis, the worse is his prognosis.