Types of brain tumors (see also table Some Tumors That Originate in or Near the Brain) can vary in their characteristics, such as their location, the people they affect most often, and the symptoms they cause.
(See also Overview of Brain Tumors.)
Gliomas
Gliomas include astrocytomas, oligodendrogliomas, and ependymomas. Astrocytomas are the most common glioma.
Some astrocytomas and oligodendrogliomas grow slowly and may initially cause only seizures. Others, such as anaplastic astrocytomas and anaplastic oligodendrogliomas, grow fast and are cancerous. (Anaplastic means that a cell has not become specialized to do a specific function—that is, the cell is undifferentiated. Undifferentiated cells in a tumor suggest that the tumor is rapidly growing.)
Astrocytomas tend to develop in young people (see also Astrocytomas in children). They can become more aggressive and are then called glioblastomas.
Glioblastomas tend to develop during middle or old age. Glioblastomas may grow so fast that they increase pressure in the brain, causing headaches and slowed thinking. If the pressure becomes high enough, drowsiness, then coma, may result.
Ependymomas develop from cells that line the spaces within the brain (ventricles). Ependymomas, which are uncommon, develop mainly in children and young adults (see also Ependymomas in children). They are uncommon after adolescence.
Symptoms of gliomas
Symptoms of gliomas vary depending on the tumor’s location.
Frontal lobes (located behind the forehead): Tumors located here can cause seizures, problems with walking, an urgent need to urinate, involuntary loss of urine (urinary incontinence), and paralysis. People may not be able to pay attention or think clearly. They may become lethargic. If tumors develop in the dominant frontal lobe (the left lobe in most people and the right lobe in some left-handers), they can cause problems with language. People may struggle to express themselves even though they know what they want to say.
Parietal lobes (located behind the frontal lobes): Tumors located here can cause loss of position sense (knowing where parts of the body are in space) and changes in sensation. People may be unable to tell whether they are being touched in 1 or 2 places. Sometimes vision is partially lost in both eyes so that neither eye can see the side of the body opposite the tumor. People may have seizures.
Temporal lobes (located above the ears at the temples): Tumors located here can cause seizures, and if they develop on the dominant side, people may be unable to understand and use language. Vision may be partially lost in both eyes so that neither eye can see the side opposite the tumor.
Occipital lobes (toward the back of the head, above the cerebellum): Tumors located here can cause partial loss of vision in both eyes, visual hallucinations (seeing things that are not there), and seizures.
In or near the cerebellum (located at the back of the head just above the neck): Tumors located here can cause nystagmus (rapid movement of the eyes in 1 direction, then a slower drift back to the original position), incoordination, unsteadiness in walking, and sometimes hearing loss and vertigo. They can block the drainage of cerebrospinal fluid, causing fluid to accumulate in the spaces within the brain (ventricles). As a result, the ventricles enlarge (a condition called hydrocephalus), and pressure within the skull increases. Symptoms include headaches, nausea, vomiting, difficulty turning the eyes upward, problems with vision (such as double vision), and lethargy. In infants, the head enlarges. Greatly increased pressure can cause herniation of the brain, which can result in coma and death.
Diagnosis of gliomas
Doctors diagnose gliomas based primarily on results of magnetic resonance imaging (MRI) and biopsy. MRI provides better results if a contrast agent (gadolinium) is used to make structures easier to see. For the biopsy, doctors may take a sample of tumor tissue before or during surgery. If it is taken before surgery, a small hole is drilled in the skull and a needle is inserted to remove the sample. The sample is analyzed to determine the exact type of tumor. The sample is also tested for genetic mutations that affect the tumor's growth. This information may help guide treatment.
Treatment of gliomas
Treatment of gliomas is similar to treatment of all brain tumors: surgery to remove the tumor, radiation therapy, and, for some types of gliomas, chemotherapy and/or immunotherapy.
Prognosis varies widely depending on the type of glioma, the location of the glioma, the genetic mutations present, and the extent of the tumor's spread.
Medulloblastomas
Medulloblastomas develop mainly in children and young adults (see also Medulloblastomas in children). They develop in the cerebellum (located at the back of the head just above the neck). They may block the drainage of cerebrospinal fluid from the spaces within the brain (ventricles). Thus, fluid may accumulate in the ventricles, causing them to enlarge (called hydrocephalus). As a result, pressure on the brain increases.
Symptoms of medulloblastomas
These tumors cause nystagmus (rapid movement of the eyes in 1 direction, then a slower drift back to the original position), loss of coordination, and unsteadiness in walking.
Medulloblastomas may spread through the cerebrospinal fluid (the fluid that surrounds the brain and spinal cord), above to the cerebrum and below to the spinal cord.
Treatment of medulloblastomas
Treatment of medulloblastomas depends on the type of medulloblastoma, the person's age, and extent of the tumor's spread. Typically in children over 3 years old, doctors remove as much of the tumor as can be done safely. Then, chemotherapy and, if necessary, radiation therapy are used. Very young children are given several chemotherapy medications after surgery to try to delay or avoid radiation therapy. (In children, some tissues are more sensitive to radiation than in adults.) In adults, surgery is followed by radiation therapy. Adding chemotherapy may improve survival.
With treatment, the percentage of people who are alive 5 years later (the survival rate) vary depending on age. Overall, rates are about
75% or more at 5 years
67% at 10 years
Meningiomas
Meningiomas are among the most common brain tumors. They are usually noncancerous but may recur after they are removed.
Meningiomas are the only brain tumor that is more common among women. They usually appear in people in middle age or older, but they can begin growing during childhood or later life. These tumors do not directly invade the brain but may compress the brain or cranial nerves, block the absorption of cerebrospinal fluid, or do both. Meningiomas can also grow into bones in the head, sometimes causing visible changes and affecting vision and hearing.
Symptoms of meningiomas
Symptoms of meningiomas depend on where the tumor develops. They may include weakness or numbness, seizures, an impaired sense of smell, changes in vision, headaches, and impaired mental function. In older adults, a meningioma may cause dementia.
Diagnosis of meningiomas
Diagnosis of meningiomas is usually based on results of magnetic resonance imaging (MRI) using a contrast agent to make structure easier to see.
Treatment of meningiomas
If meningiomas do not cause symptoms and are small, treatment consists of regular imaging to monitor them. If meningiomas cause symptoms, are enlarging, or are located in certain critical areas of the brain, doctors remove them if possible, sometimes using radiosurgery. Radiosurgery does not require an incision. Instead, it uses focused radiation to destroy the tumor.
Pineal Tumors
Tumors can develop near the pineal gland, a small structure deep within the brain. Pineal tumors usually develop during childhood and often cause early puberty, especially in boys. They can block the drainage of cerebrospinal fluid around the brain, leading to hydrocephalus (accumulation of fluid in the brain's ventricles, causing them to enlarge). As a result, pressure on the brain increases.
The most common type of pineal tumor is a germ cell tumor. (Germ cell tumors originate in cells that develop into the reproductive system in males and females. These cells are called germ cells.)
Symptoms of pineal tumors
Symptoms of pineal tumors include the inability to look up and changes in the position of the eyelid. The eyes may be unable to adjust to changes in light.
Diagnosis of pineal tumors
Diagnosis of pineal tumors typically involves magnetic resonance imaging (MRI) followed by biopsy. Blood tests are sometimes also done.
Treatment of pineal tumors
Radiation therapy, chemotherapy, radiosurgery, and surgery are used alone or in combination. Germ cell tumors are very sensitive to radiation therapy and are often cured.
Pituitary Gland Tumors
The pituitary gland, located at the base of the brain, controls much of the body’s endocrine (hormone) system. Most tumors of the pituitary gland are pituitary adenomas, which are usually noncancerous. Pituitary adenomas may secrete abnormally large amounts of pituitary hormones or block production of hormones. When large amounts of hormones are secreted, effects vary depending on which hormone is involved.
For growth hormone, extreme height (gigantism) or disproportionate enlargement of the head, face, hands, feet, and chest (acromegaly)
Cushing syndrome, causing fat and fluid to accumulate in the face and shoulders (buffalo hump), purple stretch marks on the abdomen, high blood pressure, weak bones, easy bruising, and poor wound healing
For prolactin, the cessation of menstrual periods (amenorrhea) in women, production of breast milk in women who are not breastfeeding (galactorrhea), and, in men, loss of libido, erectile dysfunction, and enlargement of the breasts (gynecomastia)
(formerly called diabetes insipidus), which causes excessive thirst and excessive urination
Pituitary gland tumors can block hormone production by destroying the tissues in the pituitary gland that secrete hormones, eventually resulting in insufficient levels of these hormones in the body.
Headaches commonly occur. Vision is affected if the tumor puts pressure on the optic nerve. Rarely, bleeding into the tumor occurs, causing a sudden headache and loss of vision.
Diagnosis of pituitary gland tumors
Magnetic resonance imaging (MRI)
Blood tests
Doctors suspect pituitary tumors in people with unexplained headaches, characteristic visual problems, or problems due to abnormalities in hormone production.
Diagnosis is usually based on MRI and blood tests to measure levels of hormones produced by pituitary tumors.
Treatment of pituitary gland tumors
Surgery or medications
Treatment of pituitary tumors depends on which hormone is being overproduced. For example, pituitary tumors that produce growth hormone are surgically removed. Sometimes, particularly if the tumor cannot be surgically removed or a lot of tissue is affected, radiation therapy is required.
Primary Brain Lymphoma
Primary brain lymphoma originates in nerve tissue in the brain, spinal cord, or meninges (layers of tissue that cover the brain and spinal cord).
Primary brain lymphoma is becoming more common, particularly among older adults and people with a weakened (immunocompromised) immune system (such as people who have end-stage HIV infection or who have had an organ transplant). The Epstein-Barr virus, which causes infectious mononucleosis, may contribute to the development of lymphoma in people with HIV infection or a weakened immune system.
Primary brain lymphoma may form several tumors in the brain or sometimes only 1. Sometimes brain lymphoma affects the retina and optic nerve in the eye because nerves from the brain extend into the eye.
Diagnosis of primary brain lymphoma
Magnetic resonance imaging (MRI)
Sometimes a spinal tap or biopsy
MRI may help doctors diagnose primary brain lymphoma. However, MRI findings may be inconclusive. Then a biopsy or spinal tap (lumbar puncture) is done.
A spinal tap is done to obtain cerebrospinal fluid (CSF) for examination under a microscope. A spinal tap may help when the diagnosis or the type of tumor is unclear. When lymphoma affects the meninges (which cover the brain and spinal cord), lymphoma cells may be detected in the CSF. However, a spinal tap cannot be done if people have a large tumor that is increasing pressure within the skull. In these people, removing CSF during a spinal tap may cause the tumor to move. The brain may be pushed sideways and downward through small openings that are normally present in the relatively rigid sheets of tissue that divide the brain into compartments. The result is herniation of the brain.
If the CSF does not contain lymphoma cells, biopsy of the brain is required.
Doctors do a slit-lamp examination to look for tumors in the retina or optic nerve at the back of eye.
Doctors do the following to make sure that the lymphoma first developed in the brain rather than elsewhere in the body and then spread to the brain:
Biopsy of bone marrow
Imaging tests of the chest, abdomen, and pelvis
These tests also help determine how extensive the lymphoma is.
Treatment of primary brain lymphoma
Corticosteroids
Chemotherapy
Radiation therapy
Corticosteroids can shrink the tumor, decrease the swelling around it, and result in rapid improvement at first. However, the improvement does not last.
Some chemotherapy agents given in high doses can affect stem cells that develop into blood cells. If such medications are used, stem cells can be removed from a person's blood before chemotherapy is started, then added back after chemotherapy. This procedure (called autologous stem cell transplantation) can restore the production of blood cells.
Some people have conditions that prevent them from having autologous stem cell transplantation. They may benefit from radiation therapy. Because primary brain lymphoma tends to spread throughout the brain, whole-brain radiation is used.
Those who are younger have a higher survival rate than older adults.
