There are more than 120 different types of brain tumors. Many tumors have different subtypes; for example, an astrocytoma can be a pleomorphic xanthoastrocytoma, a glioblastoma multiforme, or a desembryoplastic neuroepithelial tumor. Brain tumors are often assigned different grades, ranging from a Grade I (least malignant) to Grade IV (most malignant). If this is not confusing enough, the same tumors sometimes have different names and even pathologists are not always consistent in what they call them. Also, it is important to note that non-malignant, or benign, brain tumors can be just as difficult to treat as malignant brain tumors. Below is a guide to the most common types of brain tumors. Please remember that the best way of finding out information about your specific type of tumor is through your doctor.
Acoustic Neuroma (see Vestibular Schwannoma)
Astrocytoma Astrocytomas represent the most common type of glioma. They develop from the supporting cells of the brain, which are star-shaped glial cells called astrocytes. In children, most astrocytomas are considered low-grade, while in adults most are high-grade. They occur in most parts of the brain, including the brain stem. Pathologists use a grading system for astrocytomas, ranging from the least aggressive, Grade I, to the most aggressive, Grade IV. The four types of astrocytomas are pilocytic astrocytomas (Grade I), astrocytoma (Grade II), anaplastic astrocytoma (Grade III) and glioblastoma multiforme (Grade IV). Low-grade astrocytomas tend to grow slowly and are usually localized to one part of the brain. Higher-grade astrocytomas may invade surrounding tissue, grow quickly, and usually require more aggressive treatment. Symptoms The symptoms of an astrocytoma are related to the tumor's size and location. Symptoms often result from increased pressure in the brain, called intracranial pressure, which is caused by swelling in the tissue surrounding the tumor. This increased pressure may cause nausea, vomiting, irritability, and headaches. Tumor-related headaches are often more severe in the morning. Seizures are also a common symptom. However, there are sometimes no symptoms, and the tumor may be discovered during a head scan for another cause (e.g., to evaluate head trauma after a car accident). Treatment The treatment of an astrocytoma depends on many factors, including the tumor's location within the brain or spinal cord, the grade of the tumor, and whether it has invaded surrounding tissue. When possible, a biopsy is done to determine the grade and pathology of the tumor - these factors play a critical role in determining the treatment plan. Surgery is usually the first line of treatment for an astrocytoma, with the goal being to remove as much visible tumor as possible. Often, higher-grade astrocytomas have tentacle-like structures that invade surrounding tissue. This can make it difficult to surgically remove the entire tumor. An MRI can be done a few days after surgery to determine how much tumor remains, if any, and what further treatment options should be considered. Even if the entire tumor appears to have been removed on the MRI, post-operative treatment may still be recommended. Radiation therapy is often used after surgery for older children and adults to kill tumor cells that were not removed during surgery. Patients who have undergone radiation therapy after surgery usually have a better chance of long-term survival. If surgery is not an option because the tumor is located in a vital structure, radiation therapy may be used instead. Radiation can be administered in different ways depending on the tumor's characteristics. If the tumor has spread, radiation may be given to the whole brain. Your age, health, and the location of the tumor are important factors considered by your medical team when they plan your treatment. Since radiation can have a negative effect on the developing brain and nervous system in children, chemotherapy is often used in treating young children to delay using radiation.
Central Nervous System (CNS) Lymphoma Primary CNS lymphoma usually appears in the form of brain or spinal cord tumors, but it can also involve the eyes and the spinal fluid. This type of malignant brain tumor arises from the lymphocyte cells, or white blood cells, which are part of the body's natural immune system. Although the most common site of CNS lymphoma is the cerebral hemispheres, tiny tumors can be seeded throughout the brain, with larger tumors visible on a scan. It can also be spread throughout the central nervous system in the spinal fluid, but this may not appear on MRI. Although lymphomas may appear on CTscan and MRI, a precise diagnosis requires a biopsy. A spinal tap may also be performed to screen for tumor cells. CNS lymphoma does not usually spread to other parts of the body. Primary CNS lymphoma affects a small number of otherwise healthy people and a larger fraction of those who have a weakened immune system, whether from organ transplants, infection from AIDS, or other causes. The incidence of CNS lymphoma is increasing in all individuals with healthy or unhealthy immune systems. Symptoms The symptoms of primary CNS lymphoma are related to the size of the tumor and its location within the brain. A lymphoma within the brain or spinal cord can cause symptoms such as seizures, vision problems, partial paralysis affecting one side of the body, personality changes, or memory loss. If there is increased intracranial pressure, this could also cause lethargy, memory loss, mental changes, confusion, seizures, and muscles weakness. Treatment Often, the first step is surgery or a biopsy to confirm the diagnosis of CNS lymphoma. Once the diagnosis is established, steroids may be used to control brain swelling. Surgery, however, is not always an option if the tumors are very small and seeded throughout the brain. Lymphomas are more resistant when they are located in the central nervous system. Consequently, your doctor will choose drugs that cross the blood-brain barrier or give standard drugs in high enough doses to force them to cross that barrier. For years, CNS lymphoma was treated with radiation therapy because these tumors responded well to this treatment. It is now thought that chemotherapy alone can be very effective. There is an emerging consensus that methotrexate is an important chemotherapeutic agent for CNS lymphoma. Your doctors will take into account your age, health, and the tumor's location when determining the most effective treatment plan.
Ependymoma Ependymoma is a type of glioma that arises from the ependymal cells lining the ventricles within the brain and the central canal of the spinal cord. Ependymomas most often affect children, representing 10% of all childhood brain tumors, and usually arise in the cavity known as the fourth ventricle. In adults, they occur most commonly in the spinal cord. As with other brain tumors, pathologists use a grading system with ependymomas. The grading system represents how aggressive the tumor cells are and how much they resemble normal ependymal cells, with Grade I tumor cells being the least aggressive and Grade IV tumor cells being the most aggressive. There are two types of Grade 1, or benign, ependymomas: myxopapillary ependymoma, usually located in the spine, or subendymoma, usually located in the fourth ventricle. Grade II tumors most often occur in the fourth ventricle and midline area; they include papillary, cellular, and clear cell ependymomas. Papillary ependymoma is also a Grade II tumor, which is rare and located in the cerebellopontine angle. Grade III tumors, called anaplastic ependymomas, are malignant and are usually located in the cerebral hemispheres. Grade IV tumors are rare and more common in children. Symptoms The symptoms of an ependymoma are usually related to its size and location within the brain. For example, the blockage of cerebrospinal fluid can result in symptoms caused by increased pressure in the brain. Symptoms may include nausea, vomiting, irritability, seizures, and headaches. Headaches may be more severe in the morning. Infants with an ependymoma may exhibit head enlargement as a presenting symptom. Ependymomas located within the spinal cord may cause pain, tingling, numbness or weakness in the back, arms or legs. Myxopapillary ependymoma in the spine more frequently cause leg pain and numbness, while less frequently causing urinary incontinence. Treatment The usual treatment of ependymomas includes surgery followed by radiation. If the location of the tumor allows it, surgery is performed with the goal of removing as much visible tumor as possible. The amount that can be surgically removed depends on the tumor's location and proximity to healthy tissue. Since increased intracranial pressure often occurs with this type of tumor, a shunt may be used to relieve pressure in the brain. Even if the entire tumor is removed, post-operative treatment may still be recommended. Myxopapillary ependymoma does not need further treatments after a complete resection; however, it should be followed with scans. After surgery in older children and adults, radiation therapy may be used to kill tumor cells not removed during surgery. If surgery is not an option, radiation may be used alone. Chemotherapy and a form of local radiation is sometimes used, especially for recurrent tumors. In children under the age of three, chemotherapy may be used to delay radiation.
Medulloblastoma Medulloblastoma are primitive neuroectodermal tumors (PNET) that arise in the cerebellum. They are the most common malignant brain tumor among children, representing more than 25% of all childhood brain tumors. This is an aggressive and invasive tumor, which frequently spreads throughout the central nervous system by the spinal fluid. Although medulloblastomas usually occur in children, with boys more often being affected than girls, they also occur in adults. Symptoms The majority of patients with a medulloblastoma have vomiting, which is worse in the morning, and headaches. Other symptoms that may accompany this tumor include clumsiness, weakness, and problems with handwriting. In children, they may be tired, weak, irritable, and there is often a gradual decline in school performance. Treatment If the location of the tumor allows it, treatment starts with surgery with the goal being to remove as much of the tumor as possible. These primitive tumors also respond to radiation and chemotherapy. Since the tumor may spread via the spinal fluid to the spinal cord, the entire brain and spinal cord are usually irradiated after surgery. Children under the age of three are often treated with chemotherapy so the use of radiation can be delayed. If the tumor recurs, it may require a second surgery and chemotherapy.
Meningioma Meningiomas develop from meninges, the thin, protective membranes that cover the brain and spinal cord. They account for approximately 25% of all brain tumors. Although meningiomas affect people of all ages, they are most common among those in their forties and affect more women than men. Meningiomas usually grow slowly, generally do not invade surrounding normal tissue, and rarely spread to other parts of the central nervous system or body. Although the majority is non-malignant, or benign, they can recur. Meningimomas most often occur as a single tumor, but multiple tumors can also occur. Since this tends to be a slow growing tumor, it can be quite large before being diagnosed. Symptoms There can be a range of symptoms caused by a meningioma, often related to the tumor's size and location within the brain or spinal cord. In children, symptoms may result from an increase in pressure within the brain. Many common symptoms for adults and children include headaches, personality change, confusion, muscle weakness, seizures, and changes in vision. Treatment Surgery is the preferred treatment for accessible meningiomas and is more successful for these tumors than most tumor types. For those with minor symptoms or an inaccessible tumor, close observation may be the first course of action. If the entire tumor is not removed surgically, or if it recurs, additional treatment such as radiation may be used. Stereotactic radiation is often preferred to reduce damage to healthy tissue. The effectiveness of chemotherapy and hormone therapy is being investigated in clinical trials.
Metastatic Brain Tumors Although primary brain tumors account for approximately 10% of malignancies, brain metastases are the most common complication of cancer, occurring in 20-40% of oncology patients. Metastatic brain tumors, or secondary brain tumors, start as cancer cells in another part of the body and metastasize, or spread, through the blood stream to the brain or spinal cord. While lung, breast, colon, melanoma, and kidney cancer pose the greatest risk, brain metastases have been associated with many other cancers. In some cases of metastatic brain tumors, the primary cancer site cannot be found. Contrast-enhanced MRI is the best study to date for evaluating patients for brain metasteses because it is effective in detecting small metastatic tumors. Metastatic brain tumors can appear years after a primary cancer has been diagnosed and treated, and they contain the same type of cells as the cancer from which they originated. It is not uncommon to have multiple tumors. Contrast-enhanced MRI is the best study to date for evaluating patients for brain metasteses because it is a very sensitive test for detecting small metastatic tumors. The risk of developing any type of cancer increases with age, and with improvements in treatments for primary cancers and illnesses in general, people are living longer today. Consequently, there has been an increase in metastatic brain tumors, with the highest incidence in people over the age of 65. Symptoms Symptoms can be placed in two broad categories: increased intracranial pressure and focal irritation or disruption of brain function. Increased intracranial pressure can cause non-specific symptoms, such as headaches, nausea, vomiting, confusion and lethargy. Focal brain irritation or disruption of brain function will often lead to seizures, weakness, speech or language deficits, visual problems, and gait disturbances. These symptoms often have a localized value, meaning they can suggest the location of the metastatic lesion. Treatment The treatment of metastatic brain tumors depends on many factors, including the type of primary cancer, the number of metastatic tumors, the size of the tumor and location within the brain, and your response to the treatment of the original cancer. Treatment plans cannot be generalized because they are tailored to each patient. The use of steroids often relieves neurological symptoms rapidly by reducing the swelling caused by the tumor. Surgery is generally limited to tumors that are causing symptoms, especially in patients with single metastisis in patients with limited or controlled primary cancer. Whole brain radiation is useful in improving neurologic symptoms and lengthening survival - this treatment is usually recommended for most patients with brain metastases. More recently, the use of focused radiation or stereotactic radiosurgery has been used to treat small metastases, less than 3 cm in diameter, located in deeper or sensitive regions of the brain where surgical removal would carry risks of neurologic damage. Chemotherapy may be used in addition to surgery and radiation.
Oligodendroglioma Oligodendrogliomas represent 4% of all primary brain tumors. They develop from glial cells called oligodendroglia, which are the cells that form the myelin sheath (covering insulation) of the nerve fibers within the brain. They occur most often in young and middle-aged adults, with a slightly higher occurrence in men than women, but are also seen in children. The most common site of oligodendrogliomas is in the brain's cerebral hemisphere. It is rare to find pure oligodendrogliomas. It is more common to find mixed gliomas, or tumors called oligoastrocytoma, which contain a mix of astrocyte and oligodendrocyte cells. These tumors also often contain mineral deposits. As with other types of brain tumors, pathologists use a grading system to represent the malignancy of the tumor. This system ranges from grade I-IV, with grade IV being the most malignant. Symptoms The symptoms of an oligodendroglioma are related to its size and location in the brain. Oligodendrogliomas are often found in the frontal lobes and can cause personality changes or weakness on one side of the body. These tumors generally grow slowly and may be present for some time before causing symptoms. Symptoms often result from an increase in pressure within the brain, leading to nausea, vomiting, irritability, and headaches. Seizures are also a common symptom of oligodendrogliomas. Treatment The treatment for oligodendrogliomas depend on many factors including the tumor's location, grade, and whether or not the tumor has spread. If possible, and often during surgery, a biopsy is performed to determine the exact pathology of the tumor. Doctors often treat these tumors with surgery followed by chemotherapy and radiation therapy. Many of these tumors are found to be chemo-sensitive and are most often treated with PCV, a combination of the chemotherapeutic drugs procarbazine, CCNU, and vincristine. More recently, an oral medication called Temozolomide is being used in the treatment of oligodendrogliomas. If the tumor recurs, this may require a second surgery, radiation, and chemotherapy.
Pituitary Tumors Pituitary tumors, or adenomas, arise from the pituitary gland and represent 10% of all brain tumors. The pituitary gland is a small oval-shaped structure located at the base of the brain. This gland releases several chemical messengers, called hormones, which help control the body's other glands and influence the body's growth and metabolism. These tumors are almost always non-malignant and often curable. They occur at any age, but are rarely seen before puberty. Pituitary adenomas are classified into two groups: secreting and non-secreting. Non-secreting tumors are more common in the middle-aged and elderly, while secreting tumors are more common in younger adults. The majority is secreting tumors, which release unusually high levels of pituitary hormones. Since hormones affect other parts of the body, a team of medical specialists often works together to determine the treatment plan. Symptoms Most pituitary adenomas occur in front of the pituitary gland and may invade the optic chiasm, making headaches and visual loss the most common symptoms. By causing the release of pituitary hormones, secreting tumors trigger a constellation of symptoms, including impotence, cessation of menstruation, milky discharge from the breasts, abnormal body growth, hypertension, Cushing's syndrome, or an overactive thyroid gland. Non-secreting tumors may grow very slowly, cause few symptoms, and get large before they are detected. As they grow, they may cause pressure on nearby nerves, causing vision problems and/or headaches. Treatment Pituitary tumors are usually non-malignant and slow growing. The treatment will depend on the tumor's hormonal activity, size, and location. The goals of treatment often are to control hormone secretion, remove the tumor, or reduce the size of the tumor. The hormonal functions of the tumor, if any, will determine which drug is used for treatment. For example, the reduction of hormone levels through medication may in itself result in the shrinking of the tumor. Many people with secreting tumors will see an endocrinologist, a doctor who is trained in the treatment of hormone-producing glands. For a tumor not controlled by drug therapy, surgery is the standard treatment. The most common form of surgery to remove a pituitary tumor is called a "transsphenoidal approach." The tumor is reached through an incision under the upper lip or through the nasal passage. If surgery is not an option, or if the tumor is only partially removed, radiation therapy or radiosurgery may also be used for older children and adults. Replacement hormone therapy is often necessary after surgery or radiation.
Vestibular Schwannomas Vestibular schwannomas, also known as acoustic neuromas, are non-malignant tumors of the 8th cranial nerve, which contains nerve cells important for hearing and balance. Vestibular schwannomas tend to be slow growing and occur most often in adults, with women being twice as likely to develop this tumor than men. These tumors tend to grow on one side of the brain; tumors on both sides of the brain are rare. The malignant form, called a malignant peripheral nerve sheath tumor (MPNST) is extremely rare. Symptoms Acoustic neuromas can cause dizziness, a one-sided loss of hearing, or buzzing and ringing in the ear on the affected side. Facial paralysis may occur if the tumor involves the adjacent seventh cranial nerve, or the facial nerve. Treatment Schwannomas tend to be benign and are surgically removed when possible. Microsurgical techniques have been increasingly refined over the years, making the total removed of this type of tumor more likely. If surgery is not an option, stereotactic radiosurgery might be an alternative treatment. Some vestibular schwannomas are discovered accidentally while the tumor is still minute and not causing any symptoms. In this case, observation may be indicated.
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