Ependymomas are a common type of glioma formed from ependymal (glial) cellsthe basic structural and functional unit of all living things, which line the passageways of the central nervous system (CNS). The CNS is responsible for all sensory and motor functions in the body, and is composed of the brain and spinal cord.
The brain is a complex organ that is responsible for controlling all functions of the body. It has five main portions: the cerebrum, cerebellum, brainstem, pituitary gland, and hypothalamus. The cerebrum is the biggest part of the brain, and consists of the frontal, parietal, temporal, and occipital lobes. This part of the brain is responsible for voluntary movement, intelligence, and memory. The cerebellum is a small part of the brain located at the back of the head, and regulates posture and balance. The brainstem is a small, stalk-like structure towards the bottom of the brain that connects the brain to the spinal cord. It regulates many vital bodily processes, such as swallowing, breathing, and heart rate. The pituitary gland is a pea sized organ located behind the eyes, and is responsible for the production and secretion of hormones in the body. The hypothalamus is located deep within the brain, and has many important functions, such as producing and secreting different hormones, regulating temperature, and controlling appetite.
The spinal cord is a long, thin, tubular structure that extends down from the brainstem to the lower back. It is made of nerve tissuea group of cells that work together to perform a function, and is surrounded by the bones of the spine (vertebrae). The spinal cord is responsible for transmitting nerve signals from the brain to the body, and vice versa. It has motor functions (such as voluntary movement), sensory functions (such as pressure, touch, temperature, and pain), and autonomous functions (such as regulating digestion, heart rate, and bloodthe red bodily fluid that transports oxygen and other nutrients around the body pressure).
In children, an ependymoma is most commonly found in the cerebellum portion of the brain, which is responsible for voluntary movements such as walking, balance, coordination and speech. In adults, an ependymoma is more likely to be found in the spinal cord and may cause weakness in the portion of the body controlled by the nerves affecting the tumoura tissue mass that forms from groups of unhealthy cells.
Ependymomas are mostly diagnosed in young children and are more prevalent in males, however, they can develop in anyone at any age.
Types of Ependymomas
There are several types of ependymomas, which can be categorised by their location within the CNS, as well as their cellular appearance under the microscope.
Ependymoma Subtypes Based on Location
Ependymomas can be classified by their location within the CNS.
Posterior Fossa/Infratentorial Ependymoma
Posterior fossa ependymomas, also referred to as infratentorial ependymomas, are the most common subtype of ependymoma found in the posterior fossa, a small area in the skull near the cerebellum and brainstem. They can be classified into three primary categories (posterior fossa groups A and B, and subependymomas) based on cellular appearance.
The aggressiveness and prognosisto predict how a disease/condition may progress and what the outcome might be of ependymomas found in the posterior fossa vary based on the subtype diagnosed and cellular appearance.
Supratentorial Ependymoma
Supratentorial ependymomas are a less common subtype of ependymoma most commonly found within the cerebral hemispheres. They can be classified into four primary categories (ZTFA fusion-positive, YAP1-MAMLD1 fusion, supratentorial ependymomas without ZFTA or YAP1 fusion, and subependymomas) based on cellular appearance.
The aggressiveness and prognosis of ependymomas found in the supratentorial region vary based on the subtype diagnosed and cellular appearance.
Spinal Ependymoma
Spinal ependymomas are a common type of spinal tumour that develop from glial cells in the spinal cord. Unlike other types of ependymoma, this disease tends to occur in patients between the ages of 30-40, and are generally more common in males. Spinal ependymomas can be classified into four primary categories (subependymoma, myxopapillary, MYCN-amplified, and not otherwise specified).
Ependymoma Subtypes Based on Cellular Appearance
In addition to their location, ependymomas can also be categorised based on their cellular appearance.
Posterior Fossa Group A (PFA) Ependymoma
Posterior fossa group A (PFA) ependymomas are a relatively common subtype of posterior fossa ependymomas that generally occur in infants and children under six years old. It is characterised by increased DNA-methylation, which is a specific process that changes a person’s DNA sequence, and is slightly more common in males. PFA ependymoma is often aggressive, and may not have as good of a prognosis as other ependymoma subtypes.
Posterior Fossa Group B (PFB) Ependymoma
Posterior fossa group B (PFB) ependymomas are a relatively common subtype of posterior fossa ependymomas that generally occur in adolescents and adults. It is also characterised by increased DNA-methylation, however it is not as high as PFA ependymomas. Unlike most ependymoma subtypes, PFB ependymomas are slightly more common in females. This subtype generally carries more favourable prognosis than PFA ependymomas.
Supratentorial Ependymoma ZFTA Fusion-Positive
Supratentorial ependymomas that are ZFTA fusion-positive are a common type of supratentorial ependymoma that occurs when the ZFTA (zinc finger translocation associated) gene fuses together with another gene, most commonly the RELA (REL-associated) gene. Both ZFTA and RELA are responsible for coding proteins, so changes in these genes (including a fusion of the two) often results in altered DNA and potentially adverse health conditions.
Supratentorial ependymomas ZTFA fusion-positive are slightly more common in males, and tends to affect older children around the age of nine. This subtype is often aggressive, and may not have as good of a prognosis as other types of ependymoma.
Supratentorial Ependymoma YAP1 Fusion
Supratentorial ependymomas with a YAP1 fusion are a rare type of supratentorial ependymoma that occurs when the YAP1 (Yes1 Associated Transcriptional Regulator) fuses together with another gene, most commonly the MAMLD1 (mastermind like domain containing 1 gene). Both YAP1 and MAMLD1 are responsible for coding proteins, so changes in these genes (including a fusion of the two) often results in altered DNA and potentially adverse health conditions.
Supratentorial ependymomas YAP1 fusion are slightly more common in females, and tend to affect infants under the age of three. This subtype generally carries a more favourable prognosis than supratentorial ependymoma ZFTA fusion positive.
Supratentorial Ependymoma – Not Otherwise Specified (NOS)
Supratentorial ependymomas not otherwise specified (NOS) occur when the ZFTA and YAP1 fusions are absent. These tumours are very rare, and have limited data available on their aggressiveness and prognosis.
Myxopapillary Ependymoma
Myxopapillary ependymomas are a type of spinal ependymoma that most commonly develop in the lumbosacral portion of the spine. They are most commonly found in patients between the ages of 35-39, and are slightly more common in males. While these tumours can be aggressive, they often have a good prognosis.
Spinal Ependymoma – Not Otherwise Specified (NOS)
Spinal ependymomas not otherwise specified (NOS) are the most common subtype of spinal ependymomas, and are generally found in the centre of the spinal cord. This subtype is generally diagnosed between the ages of 30-40, and are most commonly diagnosed in males. While these tumours can be aggressive, they often have a good prognosis.
Spinal Ependymoma – MYCN-amplified
Spinal ependymomas MYCN-amplified are a newly recognised spinal tumour that is caused by an amplification of the MYCN gene. MYCN is responsible for coding proteins, so changes in these genes often results in altered DNA and potentially adverse health conditions. It most commonly affects young adults, and are often aggressive. Because of how rare these tumours are, there has been limited research done into the prognosis of this disease.
Subependymoma
Subependymomas are a rare type of ependymoma that can develop in the posterior fossa, supratentorial region and the spinal cord. They are most commonly found in people between 50 and 60, and are slightly more common in males. These tumours are often slow-growing, non-aggressive, and often have a good prognosis.
Treatment
When cancers are detected, they are staged and graded based on size, metastasiswhen the cancer has spread to other parts of the body, also known as mets, and how the cancera disease where abnormal cells split without control and spread to other nearby body tissue and/or organs cells look under the microscope. Stagingthe process of determining how big the cancer is, where it started and if it has spread to other areas and grading helps your doctors determine the best treatment for you. However, brain cancers are rarely staged, as they rarely spread to other parts of the body. Instead, they are generally graded.
Ependymomas are generally graded by subtype:
- Gradea description of how abnormal cancer cells and tissue look under a microscope when compared to healthy cells I (low-grade) tumours: cancer cells present as slightly abnormal and are usually slow growing.
- Grade II (intermediate-grade) tumours: cancer cells present as abnormal and grow faster than grade-I tumours.
- Grade III (high grade) tumours: cancer cells present as very abnormal and grow quickly.
Your doctor may also recommend genetic testinga procedure that analyses DNA to identify changes in genes, chromosomes and proteins, which can be used to analyse tumour DNA to help determine which treatment has the greatest chance of success, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including location, age, stage of disease and overall health.
Treatment options for ependymomas may include:
- Surgerytreatment involving removal of cancerous tissue and/or tumours and a margin of healthy tissue around it to reduce recurrence to remove as much of the tumour as possible.
- Radiation therapya treatment that uses controlled doses of radiation to damage or kill cancer cells.
- Chemotherapya cancer treatment that uses drugs to kill or slow the growth of cancer cells, while minimising damage to healthy cells.
- Clinical trialsresearch studies performed to test new treatments, tests or procedures and evaluate their effectiveness on various diseases.
- Palliative carea variety of practices and exercises used to provide pain relief and improve quality of life without curing the disease.
Risk factors
Because of how rare ependymomas are, there isn’t a lot of information surrounding the riskthe possibility that something bad will happen factors of this disease. However, a potential link has been identified between the condition neurofibromatosis type 2 (NF2), and the development of ependymomas.
Symptoms
The symptoms in people with ependymomas will vary depending on the tumour stage and location. Some of the common symptoms of ependymomas in the brain are:
- Hydrocephalusa build up of cerebrospinal fluid (CSF) in the brain, causing pressure and potentially damaging brain tissue, which carries its own set of symptoms:
- Headaches.
- Nauseato feel sick or likely to vomit and/or vomiting.
- Difficulties with eye movement.
- Difficulties with balance.
- Difficulties with walking.
- Dizziness.
- Difficulties with vision, such as increased blurriness.
- Walking difficulties.
- Difficulties controlling eye movement.
- Neck pain.
- Delayed or regressed developmental milestones.
- Seizures.
Some of the common symptoms of ependymomas in the spine are:
- Back pain.
- Numbness and weakness in limbs or trunk.
- Difficulties with urinating and bowelportion of the digestive system that digests food (small bowel) and absorbs salts and water (large bowel); also called intestines movements.
Not everyone with the symptoms above will have cancer but see your general practitioner (GP) if you are concerned.
Diagnosis
If your doctor suspects you have an ependymoma, they may order the following tests to confirm the diagnosisthe process of identifying a disease based on signs and symptoms, patient history and medical test results and refer you to a specialist for treatment:
- Physical examinationan examination of your current symptoms, affected area(s) and overall medical history.
- Neurological examinationan assessment of sensory and motor functions, such as vision, balance and coordination.
- Imagingtests that create detailed images of areas inside the body tests, potentially including:
- MRI (magnetic resonance imaging)a type of medical imaging that uses radiowaves, a strong magnet and computer technology to create detailed images of the body.
- CT (computed tomography) scana type of medical imaging that uses x-rays and computer technology to create detailed images of the body.
- Blood teststesting done to measure the levels of certain substances in the blood.
- Lumbar puncturea procedure that involves inserting a needle between two vertebrae in the lower spine and extracting a sample of cerebrospinal fluid (CSF) for analysis.
- Biopsyremoval of a section of tissue to analyse for cancer cells.
