What is a Glioma?

What is a Glioma?

A glioma is a tumor that occurs in the brain and spinal cord. Gliomas start in glial cells—which provide important structural support in the brain—and may have very different characteristics regarding their location, behavior, and response to treatment. Five-year survival rates vary depending on the tumor but range between 5 and 20%.

Types of Glioma

Types of Glioma

There are several types of gliomas, separated based on the type of tumor cells they form. Types of glioma include:

  • Astrocytomas are brain tumors that form from astrocytes. Glioblastomas are a subcategory of astrocytoma that are fast-growing and aggressive. Astrocytomas are the most common cancerous brain tumor found in adults but are also common in children.
  • Oligodendrogliomas form from oligodendrocyte cells. This type of tumor is usually slow-growing but can become more aggressive over time.
  • Ependymomas form malignant transformation of ependymal cells and are commonly found in the ventricles of the brain or spinal cord. This type of glioma is more common in children than in adults and makes up about 2% of all brain tumors.

These glioma diagnoses are made based on both the genetic information from the tumor tissue sample and how the tumor sample looks under the microscope.

How are glioma and glioblastoma different?

A glioblastoma is a type of glioma—all glioblastomas are gliomas, but not all gliomas are glioblastomas. Glioblastomas are aggressive gliomas that grow quickly and require prompt treatment.

Grades of Glioma


Microscopic images are used to grade the severity of gliomas. Tumors are commonly referred to as “low grades” (grades I and II) or “high grades” (grades III and IV). Some low-grade tumors may progress and become high-grade.

  • Grade I: These gliomas are most common in children and include pilocytic astrocytomas. These tumors rarely progress to higher grade tumors and may even be cured following aggressive surgical management.  
  • Grade II: These tumors are still considered “low grade.” They include astrocytomas and oligodendrogliomas with specific genetic mutations. Tumors in this category usually have a better prognosis than their higher-grade counterparts.
  • Grade III: Grade III gliomas include anaplastic astrocytomas and oligodendroglioma and are considered “high grade.”
  • Grade IV: All glioblastomas are considered grade IV tumors.

Signs & Symptoms of Glioma


Symptoms of glioma vary based on the tumor’s size, grade, and location. A neuro-oncologist can help determine the source of symptoms and diagnose a glioma so you can receive prompt treatment. Signs of glioma include:

  • Headaches
  • Seizures
  • Weakness (paresis)
  • Cognitive problems
  • Difficulty speaking (aphasia)
  • Nausea or vomiting
  • Memory loss
  • Dizziness
  • Personality or behavioral changes
  • Balance problems
  • Vision problems

What Causes a Glioma?


The exact cause of gliomas is not known. However, there are some risk factors that increase the likelihood of developing a glioma.



Gliomas can cause various complications, some of which are life-threatening. These include:

  • Brain hemorrhage: Bleeding in the brain
  • Hydrocephalus: A buildup of fluid inside the brain
  • Brain herniation: Compression of the brain tissue within the skull due to pressure from a tumor
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Trust NewYork-Presbyterian for Glioma Treatment

At NewYork-Presbyterian, our expert oncologists use precision medicine to diagnose gliomas and other types of brain cancer and match you with the most effective therapies available. Together, your healthcare team members will explore your options and find the best course of care for you.