What Is Oligodendroglioma?

Oligodendroglioma is a type of glioma, which means it is a tumor that begins from glial cells in the brain or spinal cord. Oligodendrogliomas most often occur in the brain and may affect nearby areas that control movement, speech, memory, sensation, vision, mood, or behavior.

In current medical classification, oligodendroglioma is defined by specific molecular findings: an IDH mutation and 1p/19q codeletion. This means that diagnosis depends not only on what the tumor looks like under the microscope, but also on molecular testing. Oligodendrogliomas are generally classified as CNS WHO grade 2 or CNS WHO grade 3 tumors.

De Novo Brain & Spine evaluates adult patients with suspected or confirmed oligodendroglioma to help determine the appropriate next step. Evaluation may include neurological examination, brain MRI, CT imaging, biopsy, image-guided tumor resection, pathology review, molecular testing, or coordination with neuro-oncology and radiation oncology when needed.

Common Signs and Symptoms

Oligodendroglioma symptoms depend on the tumor’s location, size, grade, growth pattern, and swelling around the tumor. Some symptoms develop gradually, while others may appear suddenly.

Common signs and symptoms may include:

• New-onset seizures
• Persistent or worsening headaches
• Headaches with nausea or vomiting
• Weakness, numbness, or tingling in the face, arm, or leg
• Trouble speaking, understanding speech, or finding words
• Vision changes, including blurred vision, double vision, or loss of part of the visual field
• Balance problems, dizziness, or trouble walking
• Memory problems, confusion, or difficulty concentrating
• Personality changes, mood changes, or behavior changes
• Fatigue, drowsiness, or decreased alertness

Seek emergency medical care or call 911 for a first-time seizure, sudden weakness, sudden speech difficulty, sudden vision loss, severe confusion, loss of consciousness, or a rapidly worsening headache with vomiting or neurological changes.

What Causes This Condition?

Most oligodendrogliomas develop without a clearly known cause. A diagnosis of oligodendroglioma does not usually mean that the patient did something to cause the tumor.

Possible risk factors and related medical factors may include:

• Prior therapeutic radiation exposure to the head or brain
• Rare inherited genetic conditions that may increase the risk of certain nervous system tumors
• Tumor biology, including molecular changes that help define the diagnosis

Doctors use molecular and genetic tumor features to classify oligodendroglioma and guide treatment planning. Key diagnostic features include an IDH mutation and 1p/19q codeletion. Other tumor markers may be reviewed by the care team when appropriate.

These molecular findings are not lifestyle causes. They are tumor features that help confirm the diagnosis, determine tumor classification, and guide treatment decisions.

How It Is Diagnosed?

Oligodendroglioma cannot be diagnosed by symptoms alone. Diagnosis usually requires medical history, neurological examination, brain imaging, tissue diagnosis, and molecular testing.

Common diagnostic steps may include:

• Medical history and neurological examination to evaluate seizures, headaches, strength, sensation, reflexes, vision, speech, coordination, balance, memory, and cognitive function
• MRI of the brain with and without contrast, often the main imaging study used to evaluate a suspected glioma
• CT scan of the head, especially in urgent situations or when MRI is not immediately available
• Advanced MRI techniques, such as MRI perfusion, MR spectroscopy, functional MRI, or diffusion tensor imaging when needed for treatment or surgical planning
• Stereotactic brain biopsy when tissue is needed and tumor removal is not the safest first step
• Image-guided craniotomy and tumor resection when surgery is appropriate for diagnosis, tumor removal, or relief of pressure
• Neuropathology review to determine tumor type, grade, and microscopic features
• Molecular testing, including IDH mutation testing and 1p/19q codeletion testing, which are required to confirm the diagnosis of oligodendroglioma under current classification
• Additional molecular testing when appropriate to help clarify tumor behavior or guide treatment planning

The goal of diagnosis is to confirm the tumor type, understand how the oligodendroglioma is affecting the brain, and determine whether observation, surgery, radiation therapy, chemotherapy, or additional specialty care may be needed.

Treatment Options

Oligodendroglioma treatment depends on the tumor’s grade, molecular features, size, location, symptoms, imaging findings, neurological examination, surgical risk, and the patient’s overall health. Not every oligodendroglioma requires the same treatment plan.

Treatment options may include:

• Observation with repeat MRI scans for selected tumors when monitoring is appropriate based on size, symptoms, growth pattern, and clinical judgment
• Medication for symptom control, such as anti-seizure medication when seizures occur or corticosteroids in selected situations involving swelling
• Stereotactic brain biopsy to obtain tissue when diagnosis is uncertain or when resection is not the safest first step
• Image-guided craniotomy for tumor resection to remove as much tumor as safely possible when surgery is appropriate
• Maximal safe resection, which means removing tumor while protecting important brain functions such as speech, movement, vision, memory, and sensation
• Functional brain mapping or awake brain mapping when the tumor is near areas that control language, movement, or other critical functions
• Radiation therapy, which may be recommended depending on tumor grade, symptoms, residual tumor, growth over time, or recurrence
• Chemotherapy, which may include regimens such as PCV chemotherapy or temozolomide when recommended by oncology or neuro-oncology
• Treatment for recurrent oligodendroglioma, which may include repeat surgery, radiation therapy, chemotherapy, continued monitoring, or supportive care depending on the case
• Rehabilitation and supportive care to help with strength, balance, speech, cognition, seizures, or daily function when symptoms are present

Surgery may be considered when it can help confirm the diagnosis, reduce tumor burden, relieve pressure on the brain, reduce symptoms, or support the next stage of treatment. The safest plan depends on the oligodendroglioma’s location, grade, molecular findings, and relationship to important brain structures.