Definition: Oligodendrogliomas are tumors that arise from oligodendrocytes, cells in the brain that support and insulate nerve cells. The World Health Organization classifies oligodendrogliomas as grade II (low-grade) or grade III (high-grade). A grade II oligodendroglioma can transform to a grade III oligodendroglioma over time.
Symptoms: The most common initial symptom of an oligodendroglioma is a seizure. Other symptoms depend on the location of the tumor.
Evaluation: Oligodendrogliomas are evaluated with MRI scans.
- Grade II oligodendroglioma: Surgical biopsy and removal of as much of the tumor as possible without causing significant neurological damage is the first step in the treatment of a grade II oligodendroglioma. A biopsy may be all that is possible if the tumor is located in a critical area of the brain. Focal fractionated radiation therapy may be considered to control seizures related to the tumor that cannot be controlled with seizure medications. If the tumor recurs, surgical resection, focal radiation, chemotherapy or all three will be considered.
- Grade III oligodendroglioma: Surgical biopsy and removal of as much of the tumor as possible without causing serious neurological damage is the first step in the treatment of a grade III oligodendroglioma. Focal fractionated radiation in combination with chemotherapy are usually started 2-4 weeks after surgery.
Follow-up: Long-term close follow-up with regular MRI scans is recommended to watch for tumor growth requiring further treatment.