Common Types of Brain Tumors
There are many different types of brain tumors, some of which can have several names. Even neuropathologists who diagnose these tumors are sometimes inconsistent in what they call them.
Below are descriptions of the most common types, with links to a glossary of terms that can help you understand words with which you may not be familiar.
- Glioblastoma Multiforme
- Acoustic Neuroma
- Choroid Plexus Papilloma
- Mixed Gliomas
- Brain Stem Gliomas
- Optic Nerve Gliomas
- Pineal Tumors
- Pituitary Adenomas
- Primitive Neuroectodermal Tumors
- Vascular Tumors
- Brain Cyst
This is the highest grade glioma (grade 4) tumor and is the most malignant form of astrocytomas. Although these tumors can occur at almost any age, they're most common after 50 years of age.
These tumors are sometimes called "high-grade" or "Grade IV" astrocytomas. They grow rapidly, invade nearby tissue, and contain cells that are very malignant. Glioblastoma multiforme are among the most common and devastating primary brain tumors striking adults. They are usually treated with surgery followed by radiation therapy. Chemotherapy may be used after radiation.
Oligodendrogliomas are more slow-growing tumors that usually occur in young adults. They are frequently located within the frontal, temporal or parietal lobes and cause seizures in a relatively high percentage of patients. Many oligodendrogliomas contain little specks of calcium (bone) and can easily bleed. Treatment is usually surgery, and in cases of a benign tumor, no additional chemotherapy or radiation therapy is recommended following surgery. However, in cases of anaplastic or mixed oligodendrogiomas (a more aggressive form of this tumor) both chemotherapy and radiation therapy are usually advised. There are several clinical trials in the USA and Europe which are studying newer chemotherapy treatments for this tumor type.
Ependymomas are histologically benign but often locally aggressive tumors which occur most commonly in children. They develop from cells that line both the hollow cavities of the brain and the canal that contains the spinal cord. About 85% of ependymomas are low grade and treatment usually includes surgery followed by radiation therapy. Chemotherapy is sometimes used, especially if the tumors are recurrent. A trial for the use of immunotherapy in recurrent ependymomas will be available at the Maxime-Dunitz Neurosurgical Institute in the near future.
This type of tumor is most common in people in their 20s and 30s. It develops from the remains of a spine-like structure that formed and then dissolved while the patient was developing as a fetus. Although these tumors are often slow-growing, they can metastasize (spread) or recur even after treatment. They are usually treated with a combination of surgery and radiation.
Choroid Plexus Papilloma
This is a rare, benign tumor most common in children under the age of 12. Choroid plexus papillomas grow slowly and eventually block the flow of cerebrospinal fluid causing hydrocephalus and increased intracranial pressure. This type of tumor is most effectively treated with surgery. One half of these patients will not require a ventriculoperitoneal shunt after the tumor has been removed (which resolves the hydrocephalus in half of the patients). Choroid plexus carcinoma is a rare and malignant form of this tumor that is not curable with surgery alone, but is treated with additional therapy including chemotherapy and sometimes radiationtherapy.
Craniopharyngiomas usually affect infants and children. They develop from cells left over from early fetal development. Cranipharyngiomas are often located near the brain's optic nerves and pituitary gland, a gland that releases chemicals important for the body's growth and metabolism. Treatment for these tumors usually includes surgery and in some patients, radiation therapy.
About half of all primary brain tumors are gliomas and usually occur in the lobes of the upper part of the brain. But they can also grow in other areas, especially near the optic nerve, the brain stem, and, particularly in children, the cerebellum. Gliomas are classified into several groups. These include low grade astrocytomas, anaplastic astrocytomas, and glioblastoma multiforme.
These tumors are the most common types of gliomas. They develop from abnormal, star-shaped cells called "astrocytes." After a biopsy, your doctor will probably assign a grade, or level to your diagnosis, to define which type of astrocytoma you have. Astrocytomas are graded on a scale of 1 to 4, grade 4 being the most malignant. The types and grades of these tumors are:
These are also known as "low-grade astrocytomas" or "Grade I and II astrocytomas." These tumors contain cells that are less malignant than Grade III or Grade IV tumors. They grow slowly and can sometimes be completely removed by surgery. However, even well-differentiated astrocytomas can be difficult to reach via surgery, and if they are truly inaccessible, they can be life-threatening.
Anaplastic astrocytomas are also referred to as "Grade III astrocytomas." They grow more rapidly than the low grade type, and contain cells that have malignant traits. Recommended treatment is surgery followed by radiation and chemotherapy.
The rarest form of glioma, these tumors grow relatively slowly and may occur in the brain or spinal cord. Usually they are treated with surgery.
Mixed gliomas contain more than one type of glial cell, usually astrocytes and other glial cell types like oligodendroglial cells. Treatment focuses on the most malignant cell type found within the tumor. They may be classified under anaplastic oligodendrogliomas or be called mixed gliomas, depending on the relative cell types seen by the pathologist.
Brain Stem Gliomas
Named for their location rather than for the cells they contain, brain stem gliomas are most common in children and young adults. Surgery is not usually an option used to treat these types of tumors because of their location in vital or critical areas. Radiation therapy sometimes helps to reduce symptoms and improve survival by slowing the tumor's growth.
For more information, see Frequently Asked Questions about Brain Stem Gliomas.
Optic Nerve Gliomas
Also named for their location, these tumors are found on the optic nerve and are particularly common in individuals who have neurofibromatosis. Treatment may include surgery, radiation or chemotherapy. Some of these tumors can be very slow growing and best managed by observation alone.
Meningiomas develop from thin membranes, or meninges, that cover the brain and the spinal cord. They affect people of all ages, but are most common among those older than 30 years old. Meningiomas usually grow slowly, generally do not invade surrounding normal tissue, and rarely spread to other parts of the central nervous system or body. Surgery is the preferred treatment for accessible meningiomas and is more successful for these tumors than for most other tumor types. Recurrent meningiomas may require additional treatment that includes radiation therapy.
Tumors in the region of the pineal gland account for about 1% of brain tumors. Many different types of tumor with completely different clinical and pathological characteristics occur in this region. The most common type of tumor occuring in this region is called a germinoma. Physicians usually will begin treatment with surgery or perform a biopsy to confirm the tumor type. Depending on the particular tumor, your physician may recommend therapy that includes, radiation, chemotherapy or both.
The pituitary gland, a small oval-shaped gland located at the base of the brain, releases several of the hormones which help to control the body's other glands and influence the body's growth, metabolism, and development. Doctors classify pituitary adenomas into two groups: secreting and non-secreting. Secreting tumors release pituitary hormones, triggering symptoms that might include: impotence, amenorrhea, galactorrhea, abnormal body growth, Cushing's syndrome, or hyperthyroidism. Non-secreting adenomas are generally larger when they are diagnosed and are most commonly treated with surgery and radiation therapy.
For more information, see Facts about Pituitary Adenomas
Primitive Neuroectodermal Tumors
Primitive neuroectodermal tumors (PNETs) usually affect children and young adults. Their name reflects the belief, held by many scientists, that these tumors develop from primitive cells left over from the nervous system's early development. PNETs are usually malignant, grow rapidly and can spread easily within the brain and spinal cord. In rare cases, they may spread outside the central nervous system.
Because their malignant cells often infiltrate into the brain and have a tendency to recur, PNETs are resected as completely as is safe with surgery and then treated with radiation and chemotherapy.
These tumors come from the cells that form a protective sheath around the body's nerve fibers. They're usually benign and surgically removed when possible. One of the more common forms of this tumor affects the eighth cranial nerve, which contains nerve cells important for balance and hearing. Hearing loss is a common presentation. Also known as "vestibular schwannomas" or "acoustic neuromas," these tumors may grow on one or both sides of the brain and are potentially curable with surgery or stereotactic radiosurgery.
These rare, noncancerous tumors arise from the blood vessels of the brain and the spinal cord. The most common vascular tumor is the hemangioblastoma, often linked in a small number of people to a genetic disorder called von Hippel-Lindau disease. Hemangioblastomas do not usually spread, and surgery provides the cure. A screening is recommended to rule out renal cancer, adrenal tumors and retinal abnormalities.
These tumors are benign (non-cancerous) and start in the cells that wrap around the auditory (hearing) nerve in the head. Acoustic neuromas account for about 7% of all skull tumors. Early symptoms may include loss of hearing, ringing in the ears, dizziness and vertigo. When the condition is detected early, doctors may order a magnetic resonance imaging (MRI) scan and conduct hearing tests, which may include a special technique to test nerve impulses as they travel to the brain. When tumors are small, they can be removed through microsurgical procedures, avoiding damage to the facial nerve. For larger tumors, extensive surgery many be needed. Click here for an article on recent approaches to treating acoustic neuromas.
A brain cyst will usually compress and displace adjacent brain tissue. The degree of compression and displacement depends on the location and size of the cyst, which, in turn, determines the type and severity of symptoms. For example, cysts in "eloquent areas", such as the motor, somatosensory or visual cortex will be more prone to cause symptoms than those located, for instance, in the frontal cortex. A MRI can help diagnose a cyst, but usually a biopsy is required to be certain, in which case the cyst will often be removed. If a cyst is left in place, periodic MRIs may be required to monitor it.
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