Overview of Ependymoma
What is an Ependymoma?
An ependymoma is a rare type of brain or spinal cord tumor. Receiving the diagnosis of an ependymoma can be an overwhelming experience, especially when faced with a barrage of new medical terminology. To help make sense of it all, let's begin by exploring the origin of this tumor's name.
In the world of medicine, tumors are often named by the types of cells from which they originate. Ependymomas originate from ependymal cells that are found in the brain or spinal cord. These specialized cells are responsible for producing the clear cerebrospinal fluid (CSF) that surrounds these central nervous system structures.
If you've never heard the term "ependymoma" before, you're not alone. Ependymomas are rare, accounting for 10% of all primary brain and spinal cord tumors and affecting 4 per 100,000 people. Interestingly, ependymomas have distinct patterns in their prevalence depending on age. In adults, ependymomas are more frequently found in the spinal cord, whereas in children, they tend to occur in the brain.
Ependymomas are not considered hereditary tumors. However, there are a few genetic syndromes that may lead to an increased chance of developing an ependymoma. Syndromes such as neurofibromatosis 2, multiple endocrine neoplasia 1, and Turcot syndrome can increase the likelihood of developing various tumor types, including ependymoma.
Unfortunately, the occurrence of an ependymoma cannot be prevented. There have been no identifiable causes of ependymomas, although exposure to excessive amounts of ionizing radiation may increase the risk of developing tumors in general.
Types of Ependymomas
The World Health Organization (WHO) released a new classification system for ependymomas in 2021. The new system categorizes ependymomas into different groups based on the location, molecular characteristics, and microscopic appearance of the tumor. The types of ependymomas are:
- Supratentorial ependymomas
- ZFTA fusion-positive
- YAP1 fusion-positive
- Posterior fossa ependymomas
- Group A
- Group B
- Spinal ependymomas
- MYCN-amplified
- Myxopapillary ependymoma
- Subependymoma
Each of these types have different characteristics with respect to aggressiveness (growth rate and likelihood of spreading), response to treatment, recurrence rates, and overall prognosis. The degree of aggressiveness can be communicated by the assignment of a tumor grade. The grade is determined by a pathologist and is based on the microscopic and molecular characteristics of the tumor removed by the neurosurgeon.
Grade 1 ependymomas are the least aggressive (benign), whereas Grade 3 ependymomas are the most aggressive (malignant). Grade 2 ependymomas lie somewhere in between. The response to treatment and overall prognosis generally worsens with increasing grade of the tumor. Higher grade ependymomas may grow and spread to surrounding tissues, and tend to have a higher rate of recurrence.
The only Grade 1 ependymoma is the subependymoma type. Myxopapillary ependymomas are typically Grade 2. Other ependymoma types are usually Grade 2 or 3. Thus, among ependymomas, the subependymoma subtype has the best prognosis and removal may be curative. In other ependymoma subtypes, however, rapid growth and infiltration of surrounding tissues may make it more challenging to fully remove.
Figure 1: MRI demonstrating a posterior fossa ependymoma (red arrow).
Symptoms of Ependymomas
Symptoms caused by an ependymoma depend on the location, size, and patient age at diagnosis.
Supratentorial ependymomas are those that affect the upper parts of the brain. They can be found within the substance of the brain tissue (intraparenchymal) or within the ventricles of the brain (intraventricular). Intraparenchymal ependymomas can cause a variety of symptoms based on the exact location of the tumor. Some commonly reported symptoms include:
- Seizures
- Behavioral changes
- Difficulty speaking
- Confusion
- Vision problems
- Weakness of the arms or legs
- Numbness or tingling sensation anywhere in the body
Intraventricular ependymomas create the additional problem of blocking the flow of cerebrospinal fluid, causing retention and build-up of the fluid within the brain. This can dangerously increase the pressure in the skull in a condition known as hydrocephalus. Individuals may experience headaches, vomiting, visual disturbances, drowsiness, seizures, and unresponsiveness. Emergency neurosurgical care may be required.
Posterior fossa ependymomas occur at the lower part of the brain, near the back of the head. They are most commonly seen in children. Posterior fossa ependymomas can block cerebrospinal fluid flow, causing hydrocephalus. In very young children, hydrocephalus can result in an abnormal increase in head size. Other symptoms can include loss of coordination. Many of the symptoms mentioned earlier can occur with posterior fossa ependymomas as well.
Spinal ependymomas cause symptoms that are different from those caused by ependymomas occurring in the brain. Spinal ependymomas usually are found in the mid to lower back, resulting in back pain. Other associated symptoms are weakness or numbness of the legs, difficulty passing urine or stool, and incontinence. If the ependymoma is located in the spinal cord of the neck, weakness or numbness of the arms may occur.
These symptoms may also be caused by a wide variety of other medical conditions. Visit a doctor to talk about your concerns and receive a confirmed diagnosis.
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Diagnosis of Ependymomas
Ependymomas are usually diagnosed using a combination of your doctor’s skilled clinical judgment, imaging tests, and a biopsy of the tumor. Your neurosurgeon will ask you in detail about your symptoms and your general health. Next, an MRI scan will be done to help identify the exact location of the tumor and its relation to other parts of the brain or spine. The information gathered will help to determine a diagnosis and guide the treatment strategy.
A biopsy will be performed to gather tumor tissue, which is then examined under a microscope to identify characteristics of the tumor. During a biopsy procedure, pieces of the tumor are removed and sent for analysis. In some cases, tumor removal is performed at the same time as the biopsy. The results of the microscopic and molecular analysis will determine important details about your tumor to better understand the prognosis and plan the next steps of treatment.
If you have been diagnosed with an ependymoma or are concerned about symptoms that could be caused by an ependymoma, consult a neurosurgeon who is experienced in treating such conditions. Your neurosurgeon can guide you toward the right treatment options for you.
Key Takeaways
- Ependymomas begin in cells in the brain or spinal cord that are responsible for cerebrospinal fluid secretion.
- Ependymomas in children usually occur in the brain, whereas those in adults are typically found in the spinal cord.
- Symptoms of ependymomas vary based on the location of the tumor.
- There are multiple subtypes of ependymomas, each with different aggressiveness, recurrence rates, and prognosis.
- The grade of the ependymoma can be 1, 2, or 3. Grading is determined after the microscopic and molecular analysis of the tumor and can help to predict a patient’s prognosis.
