A glioma is a tumor that arises from glial cells, the supportive cells that surround and nourish the neurons in the brain and spinal cord. Gliomas are the most common type of primary brain tumor — that is, a tumor that originates in the brain rather than spreading from elsewhere — and they include several subtypes such as astrocytoma, oligodendroglioma, and glioblastoma. Gliomas can range from slow-growing low-grade tumors to aggressive high-grade tumors, and the specific grade and subtype determine the recommended approach to treatment and follow-up.
The symptoms of a glioma depend on its location and size. Some patients have no symptoms, and the finding is identified incidentally on imaging done for an unrelated reason. Others may experience persistent headaches, seizures, subtle changes in personality or cognition, weakness on one side of the body, vision changes, or difficulty with speech. Because these symptoms overlap with many other conditions, imaging is essential for accurate evaluation. Diagnosis is confirmed by MRI characteristics and, in most cases, a tissue sample obtained surgically; the World Health Organization classification of central nervous system tumors guides how the tumor is graded and managed.
MRI is the standard of care for evaluating gliomas because it provides high-resolution images of brain soft tissue and can distinguish between tumor tissue, edema, and normal brain. A whole-body MRI can identify a previously unknown glioma and document baseline characteristics that any future scan can be compared against. Patients reading this entry may also find context in the companion brain tumor library entry and the related blog on the science of brain age, or learn more about the Whole Body Scan at MRI Wellness.
Frequently Asked Questions #
Is a glioma always cancer? #
Gliomas are a type of tumor, and the World Health Organization grades them from 1 (least aggressive) to 4 (most aggressive). Lower-grade gliomas can be slow-growing and managed with monitoring; higher-grade gliomas are treated more aggressively. All grades are evaluated by a neuro-oncology team.
What causes a glioma? #
The cause is not fully understood. Most gliomas are sporadic, meaning they arise without an identified trigger. A small subset are linked to inherited genetic conditions or to prior high-dose radiation exposure. Cell-phone use has not been shown to cause gliomas in large studies.
What are the treatment options? #
Treatment depends on grade, subtype, and location. Options can include surgery, radiation, chemotherapy, and targeted therapies. Low-grade gliomas are sometimes monitored before treatment is initiated. A multidisciplinary neuro-oncology team typically guides the decision.
Can a glioma be missed on a routine scan? #
Very small or slow-growing gliomas can be subtle on imaging, which is one reason MRI’s soft-tissue detail is so important. A board-certified radiologist reads each MRI Wellness scan and flags anything suggestive of an intracranial mass for follow-up.
What is the difference between a glioma and a glioblastoma? #
Glioblastoma is the most aggressive subtype of glioma, classified as WHO grade 4. The broader term “glioma” includes lower-grade tumors as well, which can have very different outlooks.
References #
- National Cancer Institute. “Adult Central Nervous System Tumors Treatment (PDQ).” cancer.gov.
- World Health Organization. WHO Classification of Tumours of the Central Nervous System, 5th edition.
- Mayo Clinic. “Glioma.” mayoclinic.org.
- Radiopaedia. “Glioma.” radiopaedia.org.
