Ependymoma is a tumor that grows in the brain or spinal cord, developing from cells called radial glial cells that line the fluid-filled spaces (ventricles) of the brain and the central canal of the spine. It can occur at any age but is one of the more common brain tumors in children. Ependymomas account for roughly 5% of all central nervous system tumors, and they vary widely in behavior, from slow-growing and highly treatable to aggressive and prone to recurrence.
Where Ependymomas Form
These tumors most often appear in two locations: the posterior fossa (the lower back part of the brain, near the brainstem and cerebellum) and the spinal cord. In children, the posterior fossa is the most common site. Adults are more likely to develop ependymomas in the spinal cord. Less frequently, ependymomas grow in the upper part of the brain, called the supratentorial region. In rare cases, they can even form outside the central nervous system entirely, such as in the ovaries.
Location matters because it determines which symptoms appear first, how the tumor is treated, and how well treatment works.
Symptoms by Location
Ependymomas tend to grow slowly enough that symptoms creep in gradually, which can delay diagnosis. What you notice depends almost entirely on where the tumor sits.
Posterior Fossa (Brain)
When a tumor grows near the brainstem and cerebellum, it can block the normal flow of spinal fluid, causing it to build up inside the skull. In children, this fluid buildup can cause persistent vomiting, unusual sleepiness, irritability, slowed development, and in infants, a visibly enlarging head. Loss of balance, trouble walking, neck pain, and difficulty with nerves that control the face, swallowing, and eye movement are also common.
Upper Brain (Supratentorial)
Tumors in the upper brain are more likely to cause seizures, frequent headaches, blurry vision, nausea, and changes in how you move or feel sensation in parts of your body.
Spinal Cord
Spinal ependymomas often cause a higher burden of daily symptoms than brain ependymomas. Back or neck pain is usually the first sign. Weakness in the arms or legs, numbness or tingling, difficulty walking, and bowel problems are all common. Research comparing brain and spine ependymoma patients found that those with spinal tumors reported worse physical functioning, more bodily pain, and lower energy levels overall.
Molecular Subtypes
Ependymomas are no longer classified by how they look under a microscope alone. The molecular makeup of the tumor now plays a central role in predicting how it will behave and how well it responds to treatment. Several subtypes have been identified, and the differences between them are significant.
Supratentorial ependymomas frequently carry a specific genetic fusion called ZFTA-RELA. In these tumors, two genes fuse together and hijack a signaling pathway that drives tumor growth. Recent research published in Nature found that these fused cells produce a metabolite normally made by immune cells, which the tumor co-opts to keep its own growth engine running. This discovery is opening new avenues for targeted treatments. When children with ZFTA-RELA tumors receive a complete surgical removal followed by radiation, 5-year survival rates are around 80%.
A rarer supratentorial subtype carries a YAP1 fusion. This variant tends to occur in very young children (median age around 1.4 years) and carries an excellent prognosis, with 5-year survival approaching 100%.
In the posterior fossa, two major subtypes exist. Posterior fossa type A (PF-EPN-A) is the more aggressive form, typically affecting younger children. Certain genetic changes within this subtype, particularly a gain on chromosome 1q, sharply reduce outcomes: 5-year event-free survival drops from about 82% without the change to 36% with it. Posterior fossa type B (PF-EPN-B) primarily occurs in older children and adults and carries a much better outlook, with 5-year progression-free survival of 73% and overall survival exceeding 90%.
How Ependymomas Are Diagnosed
MRI is the primary tool for detecting ependymomas. A brain or spinal MRI with contrast can reveal the tumor’s size, exact position, and whether it has spread along the spinal fluid pathways. Because ependymomas grow near the ventricles, imaging can also show whether spinal fluid flow is being blocked. After imaging, a tissue sample from surgery is analyzed to confirm the diagnosis and determine the molecular subtype, which guides treatment decisions.
Surgery as the Primary Treatment
For nearly all ependymomas, surgery is the first and most important step. The goal is to remove the entire visible tumor, a complete resection. How much tumor the surgeon can safely remove is consistently the strongest predictor of long-term outcome. In a study of 61 pediatric cases, complete resection was achieved in about 64% of patients, and both the extent of removal and achieving it in a single operation were independent predictors of how long patients remained free of tumor progression.
Complete removal is not always possible. Tumors that wrap around the brainstem or critical nerves may only be partially removed to avoid permanent neurological damage. In these cases, additional treatment becomes especially important.
Radiation After Surgery
Radiation therapy is standard after surgery for most ependymomas, particularly in children over one year of age. It targets the tumor bed to destroy any remaining cells. Proton beam therapy has become increasingly common for pediatric ependymomas because it delivers radiation more precisely, sparing surrounding healthy brain tissue. This is especially important in young children, whose developing brains are vulnerable to radiation-related side effects like cognitive changes, hormonal problems, and hearing loss.
Typical radiation doses exceed 54 Gy, and outcomes with proton therapy have been encouraging. A combined report from the University of Florida and Harvard Medical School found 7-year local control of 77%, progression-free survival of about 64%, and overall survival of 82%. One concern specific to proton therapy is a slightly higher risk of damage to the brainstem when doses exceed 54 Gy compared to traditional photon radiation, which has led to updated guidelines for brainstem dose limits.
Chemotherapy does not play a major role in treating most ependymomas, though it is sometimes used for very young children to delay or avoid radiation.
Survival and Prognosis
Survival varies considerably depending on the tumor’s location, molecular subtype, and whether complete surgical removal is achieved. For childhood intracranial ependymoma overall, the 5-year overall survival rate is about 81%, dropping to 68% at 10 years. Event-free survival, meaning the child remains alive and the tumor has not progressed, is lower: roughly 69% at 5 years and 63% at 10 years.
Among very young children (ages 1 to 3) who receive complete resection and radiation, the 5-year event-free survival is about 63% and overall survival is 87%. For children aged 3 to 21 with the same treatment, those numbers are slightly better at 71% and 86%, respectively.
Molecular subtype increasingly refines these predictions. YAP1 fusion tumors have the best prognosis. Posterior fossa type B tumors do well. ZFTA-RELA tumors fall in the middle when fully resected. Posterior fossa type A tumors with certain chromosomal changes carry the highest risk of recurrence.
Long-Term Monitoring
Ependymomas can recur years after initial treatment, which makes ongoing surveillance essential. The standard monitoring schedule is intensive early on and gradually tapers. During the first two years after completing treatment, brain MRI is typically performed every 3 months and spinal MRI every 6 months. From years 3 through 5, brain imaging shifts to every 6 to 9 months and spinal imaging to every 6 to 12 months, depending on how fully the tumor responded. After year 5, annual brain MRI continues through at least year 10, while routine spinal imaging is no longer required unless symptoms or brain findings raise concern.
If recurrence is suspected at any point based on new symptoms or imaging changes, both brain and spinal MRI are performed immediately. Recurrence is managed with repeat surgery when feasible, often followed by additional radiation. Some patients undergo multiple surgeries over many years and still achieve long-term survival, particularly with spinal ependymomas that tend to recur locally rather than spreading.