Pilocytic astrocytoma is a usually benign brain tumor in children and adolescents. Affected areas may include the cerebrum, diencephalon, spinal cord, or optic nerve. After complete surgery, recurrences do not occur.
What is pilocytic astrocytoma?
Pilocytic astrocytoma is a benign brain tumor characterized by a slow proliferation of supporting cells of the central nervous system called glial cells. It therefore also belongs to the group of gliomas. Tumors of the nervous system are divided into grades of danger according to the WHO classification. As a benign tumor, pilocytic astrocytoma has been assigned grade I. This tumor mainly affects children and adolescents. In this age group it is considered the most frequent brain tumor with a share of about 30 percent. A distinction is made between optic gliomas and brain stem gliomas. Optic gliomas affect the nerves of the visual pathway and are often associated with hereditary neurofibromatosis type 1. Pilocytic astrocytoma is characterized by the presence of dermal and bulbous tumors, often with cystic portions. It is an astrocytic tumor with a very low mitotic rate. The initial cells form fine fibrillar projections resembling hairs. They are therefore also called hair cells (pilocytes) and thus give this tumor its name. The tumor is sharply demarcated from the neighboring brain tissue. This is not infiltrated by the tumor, but only displaced.
Causes
Pilocytic astrocytoma is only one form of astrocytoma. The exact causes of astrocytomas have not been fully elucidated. In benign pilocytic astrocytoma, a genetic link is suspected. Thus, it is striking that optic gliomas are particularly common in association with neufibromatosis type 1. Neurofibromatoses are a group of genetic diseases that are passed on via an autosomal dominant mode of inheritance. For example, neurofibromatosis type 1 is a genetic defect of the NF1 gene, which is located on chromosome 17. This gene is responsible for the coding of neurofibromin. Neurofibromin regulates the signal transduction protein RAS. When neurofibromin is defective or deficient, RAS is constantly active, promoting neoplasia formation. In astrocytoma, more than 50 percent also have a defect in the tumor suppressor gene p53.
Symptoms, complaints, and signs
Symptoms of pilocytic astrocytoma also depend on where the tumor is located. Health symptoms are mainly caused by the displacement of adjacent brain tissue. If the cerebellum is affected, gait insecurities are particularly prominent. If the tumor is localized in the diencephalon, disorders related to the hypothalamus are most prominent. The hypothalamus regulates, among other things, body temperature, blood pressure, food and water intake, biorhythm and sexual behavior. Tumors in the visual pathway can cause visual disturbances and, in extreme cases, even blindness.
Diagnosis and disease progression
Overall, astrocytomas can be visualized very well by imaging techniques such as MRI or CT. With the help of computed tomography (CT), calcifications (calcifications) are also excellently detectable. Another indication of a pilocytic astrocytoma is provided by the behavior of the contrast agent. This is uniformly enriched in the center of the tumor, while a cystic appearance is present at its periphery. The suspected diagnosis can be confirmed by a biopsy. Sometimes, however, the diseased tissue can only be examined after surgical removal of the tumor, and only then can the exact nature of the tumor be determined. Often, however, the correct tentative diagnosis is already made based on the typical location of the tumor and the age of the patient.
Complications
Pilocytic astrocytoma is a benign brain tumor that can be easily removed surgically. Complications regarding possible malignant degeneration are virtually nonexistent. However, if the tumor is unfavorably located, its complete removal may not be possible. In this case, recurrences are to be expected. More serious, however, is the gradual spread of the tumor in the brain.The displacement of neighboring brain structures can sometimes lead to significant complications, which in extreme cases can be fatal. Due to the pressure on certain blood vessels in the brain, the development of a stroke is even possible. The effects of stroke depend on the severity of the triggering cerebral hemorrhage. In addition to mild symptoms that disappear after the causes of the stroke are corrected (removal of the brain tumor), permanent damage can of course remain or even death can occur due to the death of certain areas of the brain. Another complication of pilocytic astrocytoma is the development of hydrocephalus. This can then occur in the child when the brain tumor space obstructs the cerebrospinal fluid drainage within the brain. In infants or fetuses, the head then enlarges like a balloon because the bones of the skull are still soft and deformable. If it occurs later, the intracranial pressure can increase to the point of severe headaches, vomiting and seizures. If left untreated, life-threatening brain entrapment often develops.
When should you see a doctor?
Pilocytic astrocytoma, like any brain tumor, belongs in the care of a doctor, who also secures the diagnosis. Therefore, going to the doctor is necessary when the patient experiences symptoms that could indicate astrocytoma. The visit to the doctor serves either to initiate early treatment or to reassure the patient, since a comparatively much more harmless disease may be behind the symptoms. The first point of contact is always the family doctor, who can refer the patient to a radiologist or neurologist if necessary. Even after treatment has been completed, visits to the doctor are obligatory in the case of pilocytic astrocytoma. Their primary purpose is to detect a recurrence early and to treat it promptly. Consequences of therapies may also require the doctor’s visit. Radiation and chemotherapy can cause fatigue or immune dysfunction. For some patients, the diagnosis of pilocytic astrocytoma is also so stressful that they need psychological support. Psychologists, psychotherapists and psychooncologists are the appropriate contacts here. A brain tumor can cause deficits in the motor and speech areas, which can still occur after its removal. Here, the doctor is also the right address. He or she will recognize the connection between deficits and the underlying disease and refer the patient to medical specialists. Speech therapists, physiotherapists and occupational therapists are the right address for the patient in this context.
Treatment and therapy
The therapy of a pilocytic astrocytoma depends on its location and the symptoms that occur. If the location is favorable, the tumor should definitely be removed. In this case, there is also a great chance of its complete extirpation. If this is successful, the disease heals completely. Sometimes, however, the tumor is so unfavorably located that surgery is not possible. This often concerns brainstem gliomas. In this case, radiation is the treatment of choice. In any case, inoperable tumors should be monitored by constant MRI examination. The same applies to tumors that do not cause symptoms. In some tumors, puncturing the fluid-filled cysts is sufficient for a long time. Often the extensive cysts have the largest space requirement and have a disturbing effect on the adjacent tissue. Although the tumor is benign, it should still be removed in the long term if possible because it can cause irreparable damage to adjacent tissue if it continues to expand. The prognosis of pilocytic astrocytoma depends on several factors. These factors include location, rate of growth, general condition of the patient, and the possibility of complete extirpation. After complete excision of the tumor, recurrence is excluded. Malignant degeneration is extremely rare in this type of tumor. However, if the tumor cannot be completely removed, regrowth of the residual tumor will occur. But even this grows very slowly, so that even in these cases the long-term survival rate is very high. Only in cases of brainstem glioma that cannot be operated on is the prognosis poor, with a five-year survival rate of no more than 30 percent.
Outlook and prognosis
Pilocytic astrocytoma is a brain tumor that basically requires close monitoring, whether it has been removed or is merely observed.It is a benign tumor with slow growth that usually has a much better prognosis than malignant brain tumors. Nevertheless, there are complications that can make the outlook more negative. These include growth over decades, which can cause the mass to gradually become too large. Therefore, in terms of outlook, removal of the often well-demarcated tumor is often the best option if the location of the brain tumor allows it. The prognosis in pilocytic astrocytoma depends critically on the location. If the tumor can be removed without affecting important structures, the prognosis is often very good. Conversely, the outlook is somewhat less favorable. The prognosis also depends on whether recurrence occurs after surgery. Complications must also be factored into the prognosis. If the tumor has led to failure symptoms, these are not always completely reversible after surgery. The operation can also lead to limitations, for example in motor function and speech. In this case, good therapeutic care, for example by physiotherapists or speech therapists, is also helpful for the patient for further prospects.
Prevention
Prevention of pilocytic astrocytoma is not possible according to current knowledge. The disease is hereditary. If the disease has already occurred in the family or relatives, the risk of inheritance to the offspring can be clarified within the framework of a human genetic consultation.
Follow-up
Follow-up and rehabilitation are among the indispensable components of treatment for pilocytic astrocytoma. The primary tasks of tumor aftercare include detecting or averting a recurrence of the brain tumor at an early stage. In addition, conceivable secondary or concomitant symptoms should be identified and treated accordingly. Finally, aftercare offers support not only for physical complaints, but also for psychological or social problems caused by the disease or its treatment. Follow-up examinations play an important role in aftercare. A magnetic resonance imaging (MRI) is performed no later than three months after the end of therapy. Further control examinations take place at intervals of six to twelve months. After three years, a further follow-up examination is performed every two years. If necessary, endocrinological, clinical neurological or ophthalmological examinations may also be performed. In the event that the pilocytic astrocytoma could not be completely removed during surgery, the remaining benign tumor will grow again, but this happens very slowly. For this reason, the long-term survival rate is relatively high. However, if the astrocytoma is successfully removed completely, recurrence usually does not occur. During follow-up, many patients benefit from regular visits to a support group. There, they have the opportunity to exchange information with other affected individuals, which is often a great help. Contacting a support group is already possible during the treatment period.
What you can do yourself
Pilocytic astrocytoma as a benign brain tumor is removed by surgery as the first choice if the situation is favorable for this. Nevertheless, patients can also contribute to their well-being through self-help in everyday life. This applies on the one hand to the aftercare, in which a stabilization in the physical area is aimed at, but also the psychological situation can be improved by measures. Both will be explained below by way of example. In the physical area, aftercare of the wound conditions in cooperation with the treating physicians is important after an operation. If the pilocytic astrocytoma was located in an area that was damaged by the tumor growth or the operation, there are measures for the best possible regeneration, in which the patient can actively participate in everyday life. For example, if motor skills are limited, exercises guided by a physiotherapist can be performed at home. The same applies to speech exercises recommended by the speech therapist for speech disorders. In general, a healthy lifestyle with sufficient sleep, adequate drinking and dosed physical activity is also advisable for increasing general well-being. If the patient needs psychological support, for example because the diagnosis of brain tumor is difficult to process, going to a self-help group is often beneficial.Psychological counseling or talking with friends and family can also help.
