A subependymal giant cell astrocytoma is a benign brain tumor. It often occurs in connection with tuberous sclerosis.
What is subependymal giant cell astrocytoma (SEGA)?
Subependymal giant cell astrocytoma (SEGA) is a benign brain tumor that rarely occurs. It develops under the ependyma and is considered a grade I tumor according to the WHO health classification. Giant cell astrocytomas are understood to be larger tumors in which there is calcification. Aside from astrocytes, which are star-shaped small cells, large neurons are also found in giant cell astrocytomas. For hhl in English, please visit gradphysics.com.
These only show up in this type of tumor. This allows them to be easily distinguished from rapidly growing isolated astrocytomas. The latter are considered malignant brain tumors and are also not associated with tuberous sclerosis (TSC), as is the case with subependymal giant cell astrocytoma. In addition, giant cell astrocytomas grow much more slowly.
Causes
The exact causes of a subependymal giant cell astrocytoma are not known. They occur primarily in children and young adults. The peak age of the disease is under 20 years. There is often a connection between the development of a giant cell astrocytoma and tuberous sclerosis. A subependymal giant cell astrocytoma develops in around 15 percent of all patients suffering from tuberous sclerosis.
Sometimes the tumor is also the first sign of tuberous sclerosis. Tuberous sclerosis is a hereditary disease that is passed on in an autosomal dominant manner and is associated with various symptoms. The occurrence of a subependymal giant cell astrocytoma is considered an important criterion in the diagnosis of tuberous sclerosis.
The subependymal giant cell astrocytoma usually settles almost exclusively in the region of the foramen Monroi. Extensive calcification foci can be found on the tumors. Not infrequently they are traversed by septa and are cystically transformed. Other typical features of subependymal giant cell astrocytoma include relatively few mitoses and extensive multinucleated cells.
Symptoms, Ailments & Signs
A subependymal giant cell astrocytoma almost always develops in the lining of the cerebral ventricle, which is located inside the brain. If the tumor continues to grow and gets larger, it can cause significant symptoms. This includes preventing the outflow of cerebrospinal fluid (liquor) from the ventricles. This in turn creates pressure on the brain tissue.
Normally, the cerebrospinal fluid that forms in the ventricles can drain unhindered into the outer cerebrospinal fluid spaces. In this way, the brain is flushed with cerebrospinal fluid from both the outside and the inside, which creates a padding to the walls of the skull. However, obstructed drainage due to a subependymal giant cell astrocytoma causes cerebrospinal fluid to collect within the ventricle, which physicians refer to as hydrocephalus (water on the head).
Because the pressure on the tissue of the brain increases due to the outflow obstruction, those affected suffer from symptoms such as nausea, vomiting, headaches, reduced visual acuity and visual field defects. Epileptic seizures and disturbances of consciousness are also possible. In the worst case, the patient can even fall into a coma.
If, on the other hand, there is a smaller subependymal giant cell astrocytoma, this usually does not cause any symptoms. The small tumors are often discovered during routine examinations using imaging methods.
Diagnosis & course of disease
If there is a suspicion of a subependymal giant cell astrocytoma, magnetic resonance imaging (MRI) is usually performed. The small tumors can be shown well using magnetic resonance imaging. Computed tomography (CT) is considered useful to detect calcifications. This shows the calcification foci within a tumor mass located on the wall of the 3rd ventricle.
The position of the astrocytoma, the age of the patient and the radiological tumor-specific features are considered important clues. The SEGA diagnosis can be made histologically by taking a tissue sample ( biopsy ) or by histopathological examination.
The course of a subependymal giant cell astrocytoma depends on whether an underlying disease is present. Tuberous sclerosis in particular plays a role here. Without treating obstructive hydrocephalus, there is a risk of permanent damage to nerve tissue due to the sustained pressure. It is not uncommon for giant cell astrocytoma to be surgically removed.
Complications
A subependymal giant cell astrocytoma can cause a number of complications. The increasing pressure on the brain tissue initially causes symptoms such as nausea, vomiting and headaches, which increase in intensity and duration as the disease progresses. In addition, visual disturbances such as visual field defects, reduced visual acuity and double vision occur, which significantly restrict those affected in their everyday lives and can lead to accidents.
Epileptic seizures and disturbances of consciousness are also conceivable and are themselves associated with serious complications. In the worst case, the patient loses consciousness. If the giant cell astrocytoma is not treated, there is a risk of damage to the nerve tissue and, as a result, of permanent neurological disorders. Surgical removal of the brain tumor carries the usual risks: bleeding, damage to nerve cords and brain tissue, and infections.
Wound healing disorders can occur after the surgical procedure. The concomitantly prescribed painkillers and sedatives can lead to gastrointestinal disorders, pain and other complications. When the patient is being treated with medication, mTOR inhibitors occasionally cause non-infectious pneumonitis, stomatitis, or a rash. In addition, allergic reactions and symptoms of intolerance can occur and delay recovery.
When should you go to the doctor?
A doctor should always be consulted with this disease. In general, an early visit to the doctor has a positive effect on the further course of the disease and can also prevent further complications. For this reason, a doctor should be contacted as soon as the first signs and symptoms appear so that the symptoms do not worsen.
The doctor should be consulted if the person concerned suffers from very severe headaches. In most cases, this pain occurs continuously and without any particular reason. Furthermore, permanent nausea, which can be associated with vomiting, also points to this disease and should also be examined. In an advanced stage, the disease can also lead to an epileptic seizure.
First and foremost, a general practitioner can be consulted. Various examinations are then carried out by a specialist in order to detect the tumour. The further course and life expectancy depend heavily on the severity of the tumor. If an epileptic seizure occurs, an ambulance must be called immediately or a hospital must be visited.
Treatment & Therapy
The treatment of a subependymal giant cell astrocytoma depends on its extent. If the tumor is small and does not cause any symptoms, regular check-ups with magnetic resonance imaging are considered sufficient. In the context of magnetic resonance imaging or computed tomography, congestion of the liquor can be detected due to the widening of the cerebral chambers. The check-ups take place at shorter intervals.
However, if a subependymal giant cell astrocytoma causes symptoms or if the cerebral ventricles expand, surgical intervention is required in most cases. During the operation, the skullcap is opened from above. With the help of two brain spatulas, the surgeon pulls the brain tissue apart slightly. A gap forms between the spatulas, through which the surgeon carries out the intervention and operates out the tumor.
Symptoms usually resolve quickly after removal of the subependymal giant cell astrocytoma. If a surgical intervention is not considered suitable, drug therapy can also take place. For this purpose, the patient receives mTOR inhibitors in the form of tablets, which inhibit the regulatory protein mTOR and restore the balance between activating and inhibiting influences.
Prevention
Preventive measures against the development of a subependymal giant cell astrocytoma are not known. The benign tumor is often caused by tuberous sclerosis, which is one of the hereditary diseases.
Aftercare
Extensive follow-up care should follow the treatment of a subependymal giant cell astrocytoma. This mainly consists of regular neurological examinations. The timely detection of long-term damage and its treatment is important. In addition to the EEG and the neurological examination of motor functions and reflexes, imaging methods (MRT, CT) are also used for this purpose.
Long-term neurological damage such as epilepsy or chronic headaches must be treated separately. In addition, an examination for tuberous sclerosis should be carried out, since this often first manifests itself in subependymal giant cell rocytomas. If tuberous sclerosis is present, its symptoms must be treated further. If the CSF pressure is permanently elevated as a result of the subependymal giant cell astrocytoma, it must be checked regularly.
In addition to taking medication that lowers CSF pressure (Glaupax), regular lumbar punctures with CSF extraction can also take place. In addition, it may be necessary to insert a shunt that permanently drains CSF fluid from the head. If the subependymal giant cell astrocytoma could be surgically removed, the consequences of the surgical intervention (loss of visual field, paralysis) may have to be treated.
Extensive rehabilitation therapy may be necessary for this. In addition, patients suffering from a subependymal giant cell astrocytoma should strive for a cancer-preventive lifestyle. In addition to giving up smoking, artificial sweeteners and contact with chemicals and carcinogenic substances should also be avoided.
You can do that yourself
A subependymal giant cell astrocytoma is treated depending on its size and location. In many cases, smaller tumors progress without noticeable symptoms and self-help measures are limited to strict compliance with regular check-ups.
If symptoms occur, an operation is required. After such an operation, a longer hospital stay is initially indicated. Those affected should follow the doctor’s instructions and rest. The symptoms usually subside quickly. Medical check-ups are also necessary after the operation. Affected people should talk to the responsible doctor about any aftercare measures.
Patients themselves can support recovery through exercise and a healthy lifestyle. Diet should be adjusted to avoid surgical site inflammation and other ailments. It is also important to pay attention to physical signals in order to quickly identify recurrences or other complications. The doctor should be informed of any unusual symptoms. It is also advisable to take a look at the family history. If there are already cases of tuberous sclerosis in the immediate family, the probability of further astrocytomas developing is high.
