What is a benign brain tumor?
Benign brain tumors are usually defined as a group of similar cells that do not follow normal cell division and growth patterns and develop into a mass of cells that microscopically do not have the characteristic appearance of a cancer. Most benign brain tumors are found by CT or MRI brain scans. These tumors usually grow slowly, do not invade surrounding tissues or spread to other organs, and often have a border or edge that can be seen on CT scans. These tumors rarely develop into metastatic (cancerous or spreading) tumors. Most benign brain tumors can be removed; the benign tumors usually do not reoccur after removal. The exact causes of benign brain tumors are not known, but investigators have suggested that family history, radiation exposure, or exposure to chemicals (for example, vinyl chloride, formaldehyde) may be risk factors.
Benign brain tumors, however, can be life-threatening because they can compress brain tissue and other structures inside the skull, so the term "benign" can be misleading. Terminology is further complicated by some investigators who classify low-grade cancerous tumors as either "benign" or "relatively benign." Regardless, compression of brain tissue or its additional structures (for example, nerves, ventricles) by a tumor mass is a major cause of the symptoms seen with benign (and malignant) tumors.
What are symptoms of benign brain tumor?
Symptoms (signs) of benign brain tumors often are not specific. The following is a list of symptoms that, alone or combined, can be caused by benign brain tumors; unfortunately, these symptoms can occur in many other diseases:
- vision problems
- hearing problems
- balance problems
- changes in mental ability (for example, concentration, memory, speech)
- seizures, muscle jerking
- change in sense of smell
- facial paralysis
- numbness in extremities
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Most common types of benign brain tumors
The majority of benign brain tumors arise from brain or brain-associated tissue (for example, nerve tissue, blood vessels). The following is a list of the most frequently diagnosed benign brain tumors:
- meningioma - tumor arising from the membranes covering the brain and spinal cord; this accounts for about 20% of brain tumors
- schwannoma (also termed acoustic neuroma) - tumor in the 8th cranial nerve arising from Schwann cells (insulating cells of the nervous system); this accounts for about 9% of all brain tumors
- pituitary adenomas - pituitary gland tumor; this accounts for about 8% of brain tumors
- hemangioblastomasa - vascular tissue mass, sometimes cystic; this accounts for about 2% of brain tumors
- craniopharyngioma - a cystic tumor from cell remnants of Rathke's pouch (nasopharynx), usually occurring in children; this accounts for about 1%-3% of brain tumors
- choroid plexus papilloma—choroid plexus tissue (the tissue responsible for the production of cerebrospinal fluid or CSF) mass that blocks cerebrospinal fluid flow, usually in children; this accounts for less than 1% of brain tumors
Other structures such as epidermoid and dermoid cysts (cysts that arise from epithelial cells, or lining cells of body organs and cavities) are considered to be benign tumors by many physicians because they can exert a mass effect (pressure) on brain tissue similar to actual brain tumors. These are rare "tumors."
What are treatment of benign brain tumors?
Treatment of benign brain tumors is similar to other brain tumor treatments except that chemotherapy is seldom done. Treatment protocols are based on the patient's age, the location and size of the tumor, and the patient's overall condition. Brain surgery (craniotomy) with surgical removal of tumor and/or radiation therapy (for example, conventional radiation, gamma knife, proton beam) are the main treatments. Often other drugs such as corticosteroids that reduce edema (swelling) and help the brain heal are part of the treatment plan. Rarely are benign tumors untreatable.
Survival in children for all brain tumors is about 70%; long-term side effects (for example, vision problems, speech problems, decreased strength) are common. For adults, five-year survival is related to age group, with younger ages (20-44) surviving at about a 50% rate. Survival rate continues to decrease with age so that older (>65) patients have a much lower survival rate of about 5%. Survival for patients with benign tumors is usually much better for all age groups, but reliable data is sparse.
The best source of information about your benign tumor is your treatment team of doctors which is usually composed of a primary-care doctor, neurosurgeon, neurologist, radiologist and infrequently, an oncologist (a specialist in the treatment of cancer, if the tumor is considered "relatively" benign).
Medically reviewed by Joseph Carcione, DO; American Board of Psychiatry and Neurology
MedscapeReference. Brain Neoplasms.