Oligodendrogliomas come from oligodendrocytes, one of the types of cells that make up the supportive, or glial, tissue of the brain. Oligodendrogliomas are generally soft, grayish-pink tumors. They often contain mineral deposits (called calcifications), areas of hemorrhage, and/or cysts. Under the microscope, these tumor cells appear to have “short arms,” or a fried-egg shape. Sometimes oligodendrogliomas are mixed with other cell types.
Location
Oligodendrogliomas can be found anywhere within the cerebral hemisphere of the brain, although the frontal and temporal lobes are common locations.
Symptoms
Common signs of an oligodendroglioma are seizures, headaches, and personality changes. Other symptoms may also be noted including persistent weakness or numbness in an arm or leg or changes related to thinking, learning, concentrating, problem-solving, and decision-making. Symptoms may vary by location and size of the tumor.
Treatment
If the tumor is located in a region of the brain that is accessible, then the usual treatment for oligodendroglioma is surgical removal of as much of the tumor tissue as possible. In instances in which the tumor is able to be removed, surgery may be the only treatment needed. Biopsy is typically performed on tumors that are not accessible to confirm the diagnosis and help guide treatment.
If some of the tumor remains (also called “residual” tumor) or if the tumor has molecular characteristics that suggest it may be more likely to recur, radiation treatment may be recommended following surgery. Radiation therapy generally takes place over the course of a six-week time period and may be given along with chemotherapy.
Depending upon the amount of tumor that is not able to be removed (residual tumor) and the molecular characteristics of the tumor itself, chemotherapy or targeted therapy may be suggested to treat the remaining tumor. Chemotherapy may be administered via a pill or an intravenous injection. Vorasidinib, a targeted therapy, was recently approved by the FDA to treat grade 2 oligodendrogliomas with IDH mutations. This medication, taken once daily, has been shown to slow tumor regrowth.
Regular MRI scans are recommended following the diagnosis of oligodendroglioma, generally at least once per year. Patients with seizures will need to be followed for their seizure medication.
A recurring oligodendroglioma may be treated with surgery, particularly when the time between initial diagnosis and recurrence is extended. In this way, the diagnosis can be updated to reflect any molecular changes that may have occurred over time, whether they be naturally occurring or associated with any treatments including radiation, chemotherapy, or immunotherapy. They may also be treated with radiation therapy, depending on whether or how much radiation was given after the original diagnosis.
Chemotherapy/immunotherapy, targeted therapy, and clinical trials are additional options.
Prognosis
Prognosis means a prediction of outcome. This information is usually based on information gathered from groups of people with the same disease. It is important to remember these statistics are not individualized.
The proportion of patients by age group who are still alive 5 years after a diagnosis of oligodendroglioma are as follows:
- Children (ages 0-14): 94.3%
- Adolescents and Young Adults (ages 15-39): 92.7%
- Adults (ages 40+): 78.2%
Incidence
Age Distribution
Risk Factors
Molecular Classification
Molecular profiling is the detection of specific genes, proteins, or other molecules in a tumor. This information helps confirm tumor diagnosis, inform treatment options, and predict prognosis.
Oligodendrogliomas are a type of glioma that have mutations in one of two genes called IDH1 and IDH2 and are missing the two chromosomal arms, 1p and 19q. These tumors are thus named Oligodendroglioma, IDH-mutant, and 1p/19q-codeleted. Oligodendrogliomas are defined as either grade 2 or 3, with grade 3 tumors associated with a more rapid growth. In addition, grade 3 tumors appear to have abnormalities on chromosomes 9 or 10, along with unusual amounts of growth factors and proteins, which are thought to contribute to the more rapid growth of these gliomas.
Content last reviewed:
December 2024 by Elizabeth Claus, MD, PhD
