A primary brain tumor is a group (mass) of abnormal cells that start in the brain. This article focuses on primary brain tumors in adults.

See also:

• Brain tumor - metastatic (cancer that has spread to the brain)
• Brain tumor - children

Primary brain tumors include any tumor that starts in the brain. Tumors may be confined to a small area, invasive (spread to nearby areas), benign (not cancerous), or malignant (cancerous).

Tumors can directly destroy brain cells. They can also indirectly damage cells by producing inflammation, compressing other parts of the brain as the tumor grows, causing swelling in the brain, and increasing pressure within the skull.

Brain tumors are classified depending on the exact site of the tumor, the type of tissue involved, benign or malignant tendencies of the tumor, and other factors. Primary brain tumors can arise from the brain cells, the meninges (membranes around the brain), nerves, or glands.

The cause of primary brain tumors is unknown. This is because they are rare, there are many types, and there are many possible risk factors that could play a role. Exposure to some types of radiation, head injuries, and hormone replacement therapy may be risk factors, as well as many others. The risk of using cell phones is hotly debated.

Some inherited conditions increase the risk of brain tumors, including neurofibromatosis, Von Hippel-Lindau syndrome, Li-Fraumeni syndrome, and Turcot syndrome.

Tumors may occur at any age, but many specific tumors have a particular age group in which they are most common. In adults, gliomas and meningiomas are most common.

SPECIFIC TUMOR TYPES

• Astrocytic tumors include astrocytomas (less malignant), anaplastic astrocytomas, and glioblastomas (most malignant). Astrocytomas can progress over time more malignant forms, including glioblastoma.
• Oligodendroglial tumors also can vary from low grade to very malignant. Some primary brain tumors are composed of both astrocytic and oligodendrocytic tumors. These are called mixed gliomas.
• Glioblastomas are the most aggressive type of primary brain tumor. These may or may not arise from a prior lower grade primary brain tumor.

Meningiomas are another type of brain tumor. These tumors:

• Occur most commonly between the ages of 40 - 70
• Much more common in women.
• While 90% are benign, they still may cause devastating complications and death due to their size or location. Some are cancerous and aggressive.

Other primary brain tumors in adults are rare and include ependymomas, craniopharyngiomas, pituitary tumors, primary lymphoma of the brain, pineal gland tumors, and primary germ cell tumors of the brain.

The specific symptoms depend on the tumor's size, location, degree of invasion, and related swelling. Headaches, seizures, weakness in one part of the body, and changes in the person's mental functions are most common.

Symptoms may include:

• Decerebrate posture
• Decorticate posture
• Decreased coordination, clumsiness, falls
• Decreased sensation of a body area
• Double vision, decreased vision
• Emotional instability, rapid emotional changes
• Fever (sometimes)
• General ill feeling
• Headache -- a persistent headache that is new for the person, worse on awakening
• Hearing loss
• Loss of memory, impaired judgment
• Personality and behavior changes
• Positive Babinski's reflex
• Reduced alertness
• Seizures that are new for the person
• Speech difficulties
• Vomiting -- possibly accompanied by nausea; more severe in the morning
• Weakness, lethargy
• Weakness of a body area

• Absent menstruation
• Breathing, absent temporarily
• Confusion
• Dysfunctional movement
• Eye abnormalities
  • Eyelid drooping
  • Pupils different sizes
  • Uncontrollable movements
• Facial paralysis
• Hand tremor
• Hiccups
• Impaired sense of smell
• Obesity
• Swallowing difficulty
• Tongue problems
• Uncontrollable movement
• Unusual or strange behavior

A doctor can often identify signs and symptoms that are specific to the location of the tumor. Some tumors may not show symptoms until they are very large and cause a rapid decline in the person's mental functions. Other tumors have symptoms that develop slowly.

Most brain tumors increase pressure within the skull and compress brain tissue because of their size and weight.

The following tests may confirm the presence of a brain tumor and identify its location:

• CT scan of the head
• EEG
• Examination of tissue removed from the tumor during surgery or CT-guided biopsy (may confirm the exact type of tumor)
• Examination of the cerebral spinal fluid (CSF) may reveal cancerous cells
• MRI of the head

Treatment can involve surgery, radiation therapy, and chemotherapy. Brain tumors are best treated by a team involving a neurosurgeon, radiation oncologist, oncologist, or neuro-oncologist, and other health care providers, such as neurologists and social workers.

Early treatment often improves the chance of a good outcome. Treatment, however, depends on the size and type of tumor and the general health of the patient. The goals of treatment may be to cure the tumor, relieve symptoms, and improve brain function or the person's comfort.

Surgery is often necessary for most primary brain tumors. Some tumors may be completely removed. Those that are deep inside the brain or that enter brain tissue may be debulked instead of entirely removed. Debulking is a procedure to reduce the tumor's size.

Tumors can be difficult to remove completely by surgery alone, because the tumor invades surrounding brain tissue much like roots from a plant spread through soil. When the tumor cannot be removed, surgery may still help reduce pressure and relieve symptoms.

Radiation therapy is used for certain tumors.

Chemotherapy may be used along with surgery or radiation treatment.

Other medications used to treat primary brain tumors in children may include:

• Corticosteroids, such as dexamethasone to reduce brain swelling
• Osmotic diuretics, such as urea or mannitol to reduce brain swelling and pressure
• Anticonvulsants, such as phenytoin to reduce seizures
• Pain medications
• Antacids or histamine blockers to control stress ulcers

Comfort measures, safety measures, physical therapy, occupational therapy, and other such steps may be required to improve quality of life. Counseling, support groups, and similar measures may be needed to help in coping with the disorder.

Patients may also consider enrolling in a clinical trial after talking with their treatment team.

Legal advice may be helpful in creating advanced directives such as a power of attorney.

For additional information, see cancer resources.

• Brain herniation (often fatal)
  • Uncal herniation
  • Foramen magnum herniation
• Loss of ability to interact or function
• Permanent, progressive, profound neurologic losses
• Return of tumor growth
• Side effects of medications, including chemotherapy
• Side effects of radiation treatments

Call your health care provider if you develop any new, persistent headaches or other symptoms suggestive of a brain tumor.

Call your provider or go to the emergency room if you have seizures that are new, or suddenly develop stupor (reduced alertness), vision changes, or speech changes.

Buckner JC, Brown PD, O'Neill BP, Meyer FB, Wetmore CJ, Uhm JH. Central nervous system tumors. Mayo Clin Proc. 2007;82(10):1271-1286.