There are many different types of brain tumors. They are usually classified by the type of cell the tumor grows from or the part of the brain where they are located.
Brain tumors may be benign (non-cancerous) or malignant (cancerous), depending on:
- How they grow and change
- If they come back after being removed
A benign (non-cancerous) tumor does not contain cancer cells. If it is removed with surgery, it usually does not recur (come back). Most benign brain tumors have clear borders. This means the tumor tissue does not spread to nearby healthy tissue.
Even though they aren't cancerous, benign tumors can cause symptoms by pressing on parts of the brain. Symptoms depend on the tumor's size and where it is located in the brain.
Doctors at the OHSU Brain Institute are experts at treating all types of brain and central nervous system tumors, including benign tumors.
ypes of benign brain tumors include:
Acoustic neuromas are benign tumors of a nerve in your head called the 8th cranial nerve. They are also called vestibular schwannomas.
Acoustic neuromas usually grow slowly over several years. They do not spread into brain tissue, but as they get larger, they press on the brain. Larger acoustic neuromas can press on another nerve in the area called the trigeminal nerve. This nerve controls feeling in the face.
Acoustic neuromas can be small (less than 1.5 centimeters), medium (1.5 cm to 2.5 cm) or large (more than 2.5 cm). They can usually be removed with surgery, but surgery can cause complications, including:
- Weakness in the face
- Hearing loss
- Cerebrospinal fluid (CSF) leak
- Brainstem swelling
- Fluid on the brain
If you have an acoustic neuroma, talk with your OHSU Brain Institute doctor about whether surgery is the right treatment for you.
An angiofibroma is a tumor that grows in the back of the nasal cavity (area inside your head above and behind the nose). It is most common in adolescent (teenage) males.
A cholesteatoma is a skin growth in a place where skin cells do not normally grow, such as inside the ear.
A cholesterol granuloma is a rare type of tumor that can grow on a part of the skull near the ear (inside the head).
Craniopharyngiomas (also called Rathke pouch tumors, hypophyseal duct tumors or adamantinomas)
Craniopharyngiomas are rare tumors at the base of the brain. They are near the optic nerves (nerves that run from the eyes to the brain). They are also near your body's hormone centers. Because of their location, craniopharyngiomas can cause:
- Vision problems
- Hormone problems
- Growth problems in children
- Increased intracranial pressure (pressure inside the skull)
Just 1 percent of all brain tumors diagnosed in the United States are craniopharyngiomas.
Because they grow near sensitive structures, craniopharyngiomas can be difficult to remove with surgery. Talk with your OHSU Brain Institute doctor about your treatment options for craniopharyngioma.
An epidermoid cyst is a tumor that grows from cells on the brain's surface. This type of tumor is most common around the brainstem (part of the brain that connects to the spinal cord), pituitary gland and posterior fossa (space at the back of the skull).
Gangliocytomas, gangliomas and anaplastic gangliogliomas are rare tumors that start in nerve cells. They are most common in young adults.
Glomus jugulare tumors are usually located just under the base of the skull, at the top of the jugular vein. They are the most common form of glomus tumor, a very rare type of head and neck tumor.
A meningiomas is a tumor, usually benign, that comes from the meninges or dura (the tough outer covering of the brain just under the skull). Meningiomas grow slowly, and may exist for years before being found. They are most common in older patients, usually people in their 70s and 80s.
Most meningiomas are separate from healthy brain tissue. They can sometimes be removed entirely during surgery. However, they can recur (come back) after surgery, and certain types can be malignant (cancerous). About one-third of brain tumors in adults are meningiomas.
A medulloblastomas is a tumor that grows near the middle of the cerebellum (bottom part of the brain). This type of tumor grows quickly. It can block the drainage of cerebrospinal fluid (the fluid around the brain and spinal cord). If this fluid does not drain as usual, it can build up and cause increased intracranial pressure (pressure inside the skull). This causes symptoms.
Medulloblastoma cells can spread to other areas of the central nervous system, especially around the spinal cord. A combination of surgery, radiation and chemotherapy is usually necessary to control these tumors.
Pineal region tumors (pineocytomas)
Many different tumors can grow near the pineal gland, a gland that helps control the cycles of sleeping and being awake. Some of these tumors are benign (non-cancerous) and some are malignant. This makes pineal region tumors difficult to diagnose. Doctors often need to biopsy (take a tissue sample) or remove the tumor to be certain what type it is.
If you have a tumor in the pineal region, you may have headaches or symptoms of increased intracranial pressure (pressure inside the skull). The best treatment for a pineal region tumor depends on the tumor type and size.
Pituitary tumors (pituitary adenomas)
The pituitary gland is located at the base of your brain. It makes hormones that control many other glands in the body. These include the thyroid gland, the adrenal glands and the ovaries and testes (testicles). Pituitary gland hormones also control milk production by pregnant women and fluid balance by the kidneys.
Tumors in or around the pituitary gland can affect its function. The gland might make too many hormones or not enough. This can cause:
- Problems with thyroid function
- Erectile dysfunction (difficulty getting or keeping an erection)
- Breast milk (when not pregnant or nursing)
- Irregular menstrual periods
- Problems with the fluid balance in the body
- Vision problems
Most pituitary gland tumors are benign (non-cancerous). Removing a pituitary tumor with surgery makes it less likely to recur (come back). Your doctor can remove a pituitary tumor through the nose or mouth. These types of tumors can also be treated with medication to shrink tumor tissue or keep the tumor from growing.
Primitive neuroectodermal tumors (PNET)
PNET can occur anywhere in the brain. The most common place is in the back of the brain near the cerebellum (bottom part of the brain). When they occur here they are called medulloblastomas. The symptoms depend on where the tumor is located in the brain. PNET usually cause increased intracranial pressure (pressure inside the skull). These tumors are fast growing and often malignant (cancerous). They sometimes spread through the brain or spinal cord.
Schwannomas grow from the supporting cells of the nerves leaving the brain. This type of tumor is most common on the nerves that control hearing and balance. When schwannomas involve these nerves, they are called vestibular schwannomas or acoustic neuromas.
If you have a schwannoma, you might have hearing loss, loss of balance or problems with weakness on one side of the face. Because they grow near sensitive structures, schwannomas can be difficult to remove with surgery. Radiation or a combination of surgery and radiation is used to treat these tumors.