Oligodendroglioma
A brain tumor arising from the cells that insulate nerve fibers
Quick Facts
- Type: Primary brain tumor (glioma)
- Cell of origin: Oligodendrocytes
- Common location: Frontal lobes
- Common first sign: Seizures
Overview
An oligodendroglioma is a tumor that begins in oligodendrocytes, the cells responsible for making myelin, the insulating layer that wraps around nerve fibers in the brain and spinal cord. Like astrocytomas, oligodendrogliomas belong to the family of tumors called gliomas, which start in the brain's supporting glial cells.
These tumors most often arise in the frontal lobes and tend to grow relatively slowly compared with some other brain tumors. They are defined in part by specific genetic features that distinguish them from other gliomas and that often predict a better response to treatment. Many people live for years with these tumors, and treatment is tailored to the individual.
Symptoms
Because oligodendrogliomas often grow slowly, symptoms may develop gradually. The most common include:
- Seizures, which are frequently the first sign
- Headaches
- Changes in thinking, memory, or personality, especially with frontal lobe tumors
- Weakness or numbness on one side of the body
- Problems with speech, vision, or coordination
- Nausea or vomiting if pressure inside the skull rises
A first seizure in an adult, or new and worsening neurological symptoms, should always be evaluated by a doctor.
Causes
The cause of most oligodendrogliomas is unknown. They arise when oligodendrocytes develop genetic changes that cause abnormal growth. A particular combination of genetic changes, the loss of parts of two specific chromosomes, is a defining feature of these tumors and helps confirm the diagnosis.
There are few established risk factors:
- Previous radiation to the head may increase risk.
- Most cases occur without any known cause or family history.
Oligodendrogliomas are not contagious and are not usually inherited.
Risk Factors
- Adulthood, as these tumors most often occur in middle-aged adults
- Previous radiation therapy to the brain
- Male sex, which carries a slightly higher risk
For most people, no clear risk factor can be identified.
Diagnosis
Diagnosis combines imaging with examination of tumor tissue:
- MRI: The main test to find the tumor and assess its size and location; oligodendrogliomas sometimes show calcium deposits.
- Biopsy or surgery: Removing tissue to confirm the diagnosis and grade the tumor.
- Molecular testing: Looking for the characteristic genetic changes that define oligodendroglioma and help guide treatment.
- Neurological exam: Assessing strength, sensation, vision, speech, and coordination.
Treatment
Treatment is individualized and managed by a specialist team. Because of their genetic features, oligodendrogliomas often respond well to treatment.
- Surgery: Removing as much tumor as safely possible is usually the first step and may relieve symptoms.
- Radiation therapy: Often used after surgery, especially for higher-grade tumors.
- Chemotherapy: Oligodendrogliomas with their characteristic genetic changes tend to be sensitive to chemotherapy.
- Monitoring: Some slow-growing tumors may be watched closely with regular imaging.
- Supportive care: Medicines to control seizures and reduce swelling.
The plan depends on the grade, location, genetic features, and the person's overall health.
When to See a Doctor
See a doctor for new or worsening headaches, changes in thinking or personality, or new weakness, numbness, or speech problems. Seek emergency care immediately for:
- A first-ever seizure
- Sudden severe headache, confusion, or loss of consciousness
- Sudden weakness, numbness, or trouble speaking or seeing
Prompt evaluation allows for early diagnosis and treatment, which can make a meaningful difference.
Frequently Asked Questions
What is an oligodendroglioma?
It is a brain tumor that begins in oligodendrocytes, the cells that make myelin, the insulating covering around nerve fibers. It is a type of glioma and most often arises in the frontal lobes, frequently growing slowly.
Why are genetic features important for this tumor?
Oligodendrogliomas are defined by a specific combination of genetic changes involving two chromosomes. These changes confirm the diagnosis and often predict a better response to chemotherapy and radiation, which is why molecular testing is a standard part of the workup.
What is usually the first symptom?
Seizures are often the first sign, particularly in adults who have never had one before. Headaches, changes in thinking or personality, and weakness or numbness can also occur, especially with tumors in the frontal lobes.
How is an oligodendroglioma treated?
Treatment typically begins with surgery to remove as much of the tumor as safely possible, often followed by radiation and chemotherapy. Because of their genetic features, these tumors frequently respond well to treatment. Slow-growing tumors are sometimes monitored closely.
When is a symptom an emergency?
Seek emergency care for a first seizure, a sudden severe headache, confusion, loss of consciousness, or sudden weakness, numbness, or trouble speaking or seeing. These can indicate a serious brain problem needing urgent care.
References
- National Cancer Institute (NCI). Adult Central Nervous System Tumors Treatment.
- American Brain Tumor Association. Oligodendroglioma.
- Mayo Clinic. Oligodendroglioma.
- MedlinePlus, U.S. National Library of Medicine. Brain tumor.