Oligoastrocytomas belong to a group of brain tumors called “gliomas.” Gliomas are tumors that come from the glial, or supportive, cells of the brain. There are several different types of gliomas. An oligoastrocytoma is a “mixed glioma” tumor, which contains both abnormal oligodendroglioma and astrocytoma cells. Oligoastrocytomas (grade II) are considered low-grade tumors. They generally grow at a slower rate than anaplastic oligoastrocytomas (grade III), which are malignant. Oligoastrocytomas may evolve over time into anaplastic oligoastrocytomas.


These tumors can be found anywhere within the cerebral hemispheres of the brain, although the frontal and temporal lobes are the most common locations.


The most common symptoms of oligoastrocytoma are seizures, headaches, and personality changes. Other symptoms vary by location and size of the tumor.


If the tumor is accessible, standard treatment for oligoastrocytoma is surgical removal of as much of the tumor tissue as possible. Biopsy is typically performed on tumors that are not accessible to confirm the diagnosis and determine the grade of tumor.

Your doctor may talk with you about chemotherapy as part of the treatment plan. Chemotherapy may also be used in infants and very young children to delay radiation therapy until the patient is older.


“Prognosis” is the medical term for a prediction of life expectancy. Keep in mind that these predictions are estimates. When your doctor talks with you about prognosis, s/he will take into account your age, the location of the tumor, grade of the tumor cells, whether your tumor has deletions of 1p and 19q, and the amount of tumor removed during surgery. Low-grade oligodendrogliomas tend to be slow growing tumors. Anaplastic oligodendrogliomas are more aggressive tumors which grow more quickly. Oligoastrocytoma growth generally depends on the percent of astrocytoma in the tumor, as astrocytomas tent to grow more rapidly than oligodendrogliomas. Scientists continue to study the impact of natural biologic differences amongst all of these tumors and the role of various treatment plans.


About 40% of primary brain tumors are gliomas. Mixed gliomas, primarily oligoastrocytomas, account for 5-10% of gliomas and 1% of all brain tumors. Oligoastrocytomas develop in young and middle-aged adults (ages 30 to 50). Very few children are diagnosed with oligoastrocytoma.

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