Ependymomas are brain tumors that arise from ependymal cells. The most common surgical treatment for ependymoma is craniotomy and surgical removal, and the most common nonsurgical treatment is stereotactic radiosurgery.
Ependymomas, a type of glioma, are uncommon, accounting for 1.9% of primary brain tumors among adults and 9% among children. Ependymomas can arise in the brain or spine.
When these tumors occur in the brain, they are typically described as arising in either the supratentorial or infratentorial region of the brain. The terms supratentorial and infratentorial describe each region in relation to the tentorium.
- The supratentorial region makes up the upper two-thirds of the brain. It includes the cerebrum and the lateral and third ventricles.
- The infratentorial region makes up the lower third of the brain. It includes the brainstem, cerebellum, and fourth ventricle.
Ependymomas are assigned a grade that reflects the appearance of the tumor cells under a microscope. Grade I designates a typical tumor cell appearance, Grade II a slightly atypical tumor cell appearance, and Grade III a significantly atypical tumor cell appearance.
Ependymomas are broken down into the following major types:
- Subependymoma (Grade I): This type is slow-growing and benign; it arises near a ventricle.
- Myxopapillary ependymoma (Grade I): This type is usually slow-growing and benign; it is found in the spine.
- Ependymoma (Grade II): The most common, this type is typically benign and found along the ventricles in either the infratentorial region or the spine. This type is further categorized—on the basis of how the cells look under a microscope—as papillary ependymoma, clear cell ependymoma or tanycytic ependymoma.
- RELA fusion–positive (Grade II or III): This is a new designation, added in 2016. This type is characterized by a molecular abnormality, RELA, that promotes tumor formation and growth. This tumor type is found in the supratentorial region.
- Anaplastic ependymoma (Grade III): These are the fastest growing ependymomas and are malignant. They tend to occur in the infratentorial region.
Subependymomas and myxopapillary ependymomas, the Grade I tumors, are easier to treat than the Grade II and Grade III tumors, which tend to recur after initial treatment. However, in general, ependymal tumors tend to not invade nearby tissue but instead displace it as they grow, making surgical removal of many of these tumors possible.
About 10–15% of ependymomas metastasize, via the cerebrospinal fluid, to other areas in the central nervous system. It is rare for an ependymoma to metastasize outside the central nervous system.
Symptoms are largely determined by the patient’s age, the location of the tumor, and the size of the tumor.
Ependymomas cause symptoms by compressing surrounding structures and increasing intracranial pressure. If a tumor blocks the cycling of cerebrospinal fluid through the ventricular system, hydrocephalus can occur, further increasing intracranial pressure.
Signs of increased intracranial pressure include nausea, vomiting, lethargy, and headache that is most pronounced upon waking in the morning because that is when pressure is highest within the skull.
A very young child with hydrocephalus may also have an enlarged head if the cranial sutures have not yet closed.
Tumors in the infratentorial region tend to cause papilledema, nystagmus, and ataxia; and tumors in the supratentorial region tend to cause cognitive impairment, hemiparesis, visual loss, and aphasia.
Other symptoms may include changes in personality and seizures.
A neurological examination is usually conducted to identify any problems and establish symptoms. This exam includes assessment of hearing, eye movements, sense of smell, sensation, motor function, swallowing, balance, and coordination.
The key to diagnosing ependymomas is imaging. Computed tomography (CT) and magnetic resonance imaging (MRI) scans can show the tumor and surrounding brain tissue. MRI scan is the imaging study of choice because it yields superior tumor detail and may need to be conducted on the head and spine to detect metastases. Contrast enhancement may be used with either study to enhance the image of the tumor.
To confirm a diagnosis, biopsy is required. The biopsy sample is almost always taken during surgery to remove the tumor.
The exact cause of ependymomas is currently not well understood.
Ependymomas are usually sporadic, not familial; however, individuals with the rare genetic condition neurofibromatosis type 2 are at risk for developing these tumors. Also, abnormalities on chromosome 22 have been shown to be associated with developing an ependymoma.
Among children, about 90% of ependymomas arise in the skull, while among adults most develop in the spine. Uncommon later in life, ependymomas account for only about 2–3% of adult primary brain tumors.
Ependymomas are usually diagnosed around age 4, but about one-third are diagnosed before age 2.
At Columbia, our experienced neurosurgeons use the most advanced surgical techniques to treat ependymomas.
The standard surgical treatment for these tumors is brain tumor surgery. To surgically resect the tumor, a neurosurgeon performs a craniotomy, providing access to the tumor.
The outcome of surgery largely depends on the extent of tumor resection. Complete resection is the goal, but sometimes the tumor is attached to, or too near, critical structures, making complete resection impossible. Instead, subtotal resection is performed. Our neurosurgeons remove as much tumor as possible while also preserving nearby structures and overall function.
Resecting the tumor may resolve hydrocephalus. Otherwise, a neurosurgeon can insert a shunt to divert the cerebrospinal fluid, restoring normal intracranial pressure and relieving symptoms.
Adjuvant treatment with radiotherapy is used to treat residual tumor and tumor recurrence. However, physicians avoid radiotherapy in children younger than three years old because of the risk of negative effects on the developing brain. Instead, chemotherapy may be used for these young children and then radiotherapy used once they are older.
Radiotherapy can be administered in a variety of ways, one of which is stereotactic radiosurgery—a noninvasive, highly precise means of delivering radiation to tumor cells.