Overview

A benign brain tumor is a growth of cells in or near the brain that is not cancerous. Benign brain tumors may start in the brain. Or they may start in nearby structures, such as the membranes that cover the brain, the pituitary gland, or the nerves involved in hearing and balance.

Benign brain tumors generally do not spread to distant parts of the body the way cancerous tumors can. Many benign tumors grow slowly. But a benign brain tumor still can be serious. It can cause symptoms if it presses on brain tissue, nerves, blood vessels or pathways for cerebrospinal fluid. Cerebrospinal fluid is the fluid that surrounds the brain and spinal cord.

Benign brain tumors often can be monitored or treated with surgery, radiation therapy or radiosurgery. Medicines may be used for some types, such as certain pituitary tumors. Symptoms and treatment for a benign brain tumor depend on the tumor's type, size, location, growth rate and molecular features and a person's overall health.

Types

There are many types of benign brain tumors. The type is based on where the tumor starts and what kinds of cells make up the tumor. Common types include:

  • Meningioma. A meningioma starts in the membranes that cover the brain and spinal cord, called the meninges. Meningioma is the most common type of benign brain tumor in adults.
  • Pituitary adenoma. This type starts in the pituitary gland, a small gland at the base of the brain. Pituitary adenomas may affect hormone levels. They also may affect vision if they press on the optic nerves or optic chiasm. The optic chiasm is the place at the base of the brain where the two optic nerves cross.
  • Vestibular schwannoma, historically referred to as acoustic neuroma. This tumor starts on a nerve involved in hearing and balance. Vestibular schwannomas may cause hearing loss, ringing in the ear, balance problems or dizziness.
  • Craniopharyngioma. This type starts near the pituitary gland and the optic nerves. It may affect hormone levels, growth, vision and other functions.
  • Hemangioblastoma. This rare, benign tumor often forms in the brain or spinal cord. Hemangioblastoma may happen on its own or as part of a genetic condition called von Hippel-Lindau disease.
  • Glioma. Glioma is a growth of cells that starts in the brain or spinal cord. Some gliomas grow slowly and are considered low grade. These may include pilocytic astrocytoma or ganglioglioma. Even when a glioma grows slowly, it may need long-term follow-up because it can grow, come back after treatment or change over time.

Symptoms

Some benign brain tumors don't cause symptoms right away. These tumors may be found during an imaging test done for another reason. When symptoms happen, they depend on the tumor's size, location and growth rate. Even a benign tumor can cause serious symptoms because of where it is and how it affects nearby brain structures.

Symptoms of a benign brain tumor may include:

  • Headache or pressure in the head.
  • Nausea or vomiting.
  • Seizures.
  • Vision changes.
  • Hearing changes.
  • Balance problems or dizziness.
  • Weakness or numbness in part of the body.
  • Trouble speaking or understanding language.
  • Changes in memory, thinking, mood or personality.
  • Fatigue.
  • Menstrual changes, changes in sexual function, excessive thirst or urination, or unexplained weight changes caused by hormone changes, depending on tumor type.

Certain tumors may cause specific symptoms. A pituitary tumor may affect hormone levels or vision. A vestibular schwannoma, also called an acoustic neuroma, may affect hearing and balance. A tumor in or near the cerebellum may affect coordination and walking.

Symptoms in children

Children may not always be able to describe symptoms clearly. A child with a benign brain tumor may seem unusually tired, have trouble with school, act differently or lose skills they had already learned. Infants may have an increasing head size. Symptoms also may include nausea and vomiting, vision changes, balance problems or a seizure.

When to see a doctor

Make an appointment with a healthcare professional for symptoms that are new, don't go away or get worse over time. Seek emergency care for a first seizure, sudden weakness or numbness, sudden trouble speaking, sudden vision loss, confusion, repeated vomiting, or a severe headache that comes on suddenly or keeps getting worse.

Causes

The cause of most benign brain tumors isn't known. Most primary brain and other central nervous system tumors happen sporadically. This means they happen without a known inherited cause. Some tumor types have been linked to changes in genes or chromosomes. These changes can affect how cells grow and behave.

Some benign brain tumors are linked to genetic conditions that can run in families.

Examples include:

Risk factors

Factors that may increase the risk of a benign brain tumor depend on the tumor type. For many people, there is no clear risk factor.

Risk factors may include:

  • Age. Some benign brain tumors become more common with age. Meningiomas, for example, increase in incidence with age, especially after age 65.
  • Sex. Meningiomas are more common in women than in men.
  • Family history or inherited risk. Some inherited conditions can increase the risk of certain benign brain tumors.
  • Radiation exposure. Exposure to ionizing radiation has been linked to some brain tumors, including meningiomas, gliomas and nerve sheath tumors.

Research has not shown a convincing link between brain tumors and head injury, occupation, cell phone use, diet or electromagnetic fields.

Complications

A benign brain tumor is not cancer. But it still can cause serious health issues. Complications depend on the tumor type, size, location and growth rate. Prompt evaluation and ongoing follow-up can help reduce the risk of serious complications.

Possible complications include:

  • Seizures. A brain tumor can irritate nearby brain tissue and lead to seizures.
  • Pressure in the brain. A tumor may block the flow of cerebrospinal fluid and cause fluid to build up in the brain. Cerebrospinal fluid is the fluid that surrounds the brain and spinal cord. Buildup of this fluid can cause nausea, headaches and, sometimes, vomiting.
  • Vision problems. Tumors near the optic nerves, the optic chiasm where the optic nerves cross, or pituitary gland may cause vision changes or vision loss.
  • Hearing and balance problems. Vestibular schwannomas, also called acoustic neuromas, can affect hearing and balance. Larger tumors may increase the risk of hearing loss.
  • Hormone problems. Pituitary tumors can cause the pituitary gland to make too much or too little of certain hormones. This may affect growth, sex hormones, thyroid function, stress hormone levels, menstrual periods, fertility, energy level or body changes.
  • Changes in movement, speech, thinking or memory. Tumors can affect nearby brain areas that control movement, language, thinking, memory or personality.
  • Tumor growth or recurrence. Some benign brain tumors grow over time or come back after treatment. Long-term follow-up imaging may be needed. 

Prevention

There is no known way to prevent most benign brain tumors. Many happen sporadically, which means they happen without a known inherited cause. Most people with a benign brain tumor do not have a clear risk factor.

Some benign brain tumors are linked to inherited conditions, such as neurofibromatosis, von Hippel-Lindau disease, tuberous sclerosis or multiple endocrine neoplasia, type 1. If a condition like this runs in your family, genetic counseling may help you understand your risk and whether screening is recommended.

By Mayo Clinic Staff