Brain Tumor Health Article
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Definition
A brain tumor is an abnormal growth of tissue, either malignant (cancerous) or benign (noncancerous), in the brain. Each year, more than 17,000 brain tumors are diagnosed in the United States.
Benign brain tumors
A benign brain tumor is composed of slow-growing noncancerous cells that never spread (by local extension or any other means) beyond the site where they originate. Common benign tumors are meningiomas, acoustic neuromas, pituitary gland tumors, craniopharyngiomas, germinomas, pinealomas, and hemangioblastomas. Even though a tumor is benign it may still be dangerous because, depending on its location, it may be inoperable and/or affect one or more brain functions.
Benign brain tumors have clearly defined borders, can often be removed completely, especially if they are on the brain's surface, and are unlikely to recur. Benign brain tumors do not infiltrate nearby tissues but as they continue to grow can cause severe pain, permanent brain damage, and death. Benign brain tumors sometimes become malignant.
Malignant brain tumors
A brain tumor is considered malignant if it contains cancer cells. Unlike other tumors, these spread by local extension and rarely metastasize beyond the brain. About half of all brain tumors are malignant.
Malignant brain tumors do not have distinct borders. They tend to grow rapidly, increase intracranial pressure, and metastasize to other parts of the brain or spinal cord. It is highly unusual for malignant brain tumors to spread beyond the central nervous system (CNS).
Primary brain tumors
Primary brain tumors originate in the brain. They represent about 1% of all cancers and 2.5% of all cancer deaths.
Metastatic or secondary brain tumors
Most brain tumors do not originate in the brain; they are metastases from other primary cancer sites. Approximately 25% of all cancer patients develop secondary or metastatic brain tumors when cancer cells spread from another part of the body. Secondary brain tumors are most apt to occur in patients who have melanoma, breast, colon, kidney, or lung cancer. Brain metastases can develop on any part of the brain or spinal cord.
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Author Info: Barbara Wexler, The Gale Group Inc., Gale, Detroit, Gale Encyclopedia of Nursing and Allied Health, 2002 |
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