Glioma

Types

The most common form of primary brain tumor is called a glioma. There are four types of gliomas: astrocytomas, ependymomas, oligodendrogliomas and mixed gliomas.

• Astrocytomas. Astrocytomas are the most common glioma and can occur in most parts of the brain (and occasionally in the spinal cord). Types of astrocytomas include:
• Pilocytic astrocytoma (grade I). These uncommon tumors can often be treated surgically by removing the tumor (resection). If your surgeon is unable to remove the entire tumor, it may remain inactive or be successfully treated with radiation.
• Low-grade astrocytoma (grade II). Grade II tumors are infiltrative, meaning the cells penetrate into the surrounding normal brain, making surgical treatment more difficult. Your doctor may recommend radiation or chemotherapy after surgery. However, if untreated, most grade II tumors eventually evolve into more aggressive tumors (grade III or IV) and cannot be treated with surgery and radiation therapy.
• Anaplastic astrocytoma (grade III). People with these tumors may experience seizures, neurological issues, headaches or changes in mental state. The standard initial treatment is to remove as much of the tumor as possible, followed by radiation therapy.
• Glioblastoma (grade IV). Glioblastoma is the most common and aggressive astrocytoma. These tumors tend to penetrate throughout the area of the brain where the tumor is located, making them more difficult to treat. Surgical removal is the main treatment, generally followed by radiotherapy and chemotherapy. Clinical trials available at Mayo Clinic are exploring new treatments for people with newly diagnosed glioblastomas and those whose tumors have returned.
• Ependymoma. Ependymomas begin in cells lining the brain passageways that contain fluid that protects the brain and spinal cord (cerebrospinal fluid). These tumors are rare and can be found anywhere in the brain or spine. Surgical removal is typically recommended for low-grade brain and spinal tumors. After surgery, any leftover tumor tissue in the brain is usually treated with radiation therapy.
• Oligodendrogliomas. These tumors begin in cells called oligodendrocytes, which support and nourish the cells that transmit nerve impulses. Oligodendrogliomas are normally found in the main part of the brain (cerebrum). Treatment options include surgery, radiation and chemotherapy.
• Mixed gliomas. Mixed gliomas have more than one type of tumor cell, including astrocytes, ependymomas and oligodendrocytes. The most common site for a mixed glioma is the cerebrum. Treatment recommendations are based on which of the cell types is most aggressive.