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Craniopharyngiomas.
These are benign tumors that occur in the area of the pituitary but they do not have the ability to secrete hormones. These tumors, which account for about 5 percent of primary brain tumors, commonly appear during childhood and are thought to be remnants of structures that inappropriately remained in place after embryonic development. It causes symptoms by putting pressure on the pituitary gland and by extending into adjacent areas.
Most craniopharyngiomas can be cured by neurosurgery. Blockage of flow of the cerebrospinal fluid may require shunting.
Tumors of the pineal gland.
Four different kinds of benign tumors are known to develop in the pineal gland, a tiny structure that is located near the center of the brain, but they are quite rare, accounting for less than one percent of all brain tumors. These rare growths develop in children and young adults causing movement disorders and mental deterioration. Because the pineal gland is very near the nerve center that controls upward movement of the eyes, patients with this disease often are unable to look up. Surgery, although technically difficult because of the tumor's relatively inaccessible location, is now more frequently successful in achieving cure. Although the pineal gland is thought to act as a biological clock and may exert some influence over other glands, its removal has no identifiable effect. Radiation is effective in shrinking these tumors and retarding their growth. Shunting may be necessary.
Tumors of the spinal cord.
The spinal cord, which is encased in the vertebral column, may be afflicted by benign, cancerous or metastatic tumors. All create symptoms by compressing the spinal cord or by pressing on nerve roots as they leave the spinal cord.
Pain, loss of sensation, paralysis, and incontinence are characteristic symptoms, which are related to the position of the tumor along the length of the cord. Most spinal cord tumors grow slowly, but rapid progression of symptoms possibly because of interference in the local blood supply is a neurosurgical emergency that, unless treated, can lead to permanent loss of function below the tumor within twelve to twenty-four hours.
The diagnostic investigation of cord tumors is straightforward. It includes a history and physical examination, X rays of the spine, and CT scans. Lumbar puncture is useful but should be performed at the time of a myelogram, a contrast study in which an opaque iodine compound is injected into the spinal fluid to outline the tumor on X-ray films.
Surgery and radiation are the only treatment options. About 25 percent of cord tumors are metastatic in origin and both radiation therapy and surgery are very useful in preventing paralysis and incontinence. Advances in surgery, including microsurgery and the use of lasers and electric coagulation, have increased the percentage of patients who achieve satisfactory results, a (act of special importance since about 35 percent of spinal cord tumors are benign and potentially curable.
Radiation therapy is appropriate if time is not of immediate concern and the diagnosis is known. Steroids are administered to reduce the edema and swelling that normally occur around central nervous system tumors.
About 15 percent of spinal cord tumors are meningiomas, affecting the protective covering of the cord. Surgery can achieve excellent results if the more important nerve tracks that are closely amassed within the cord can be preserved. Patients with spinal cord gliomas do poorly while those with metastases from myeloma or lymphoma tend to follow a clinical course that reflects the overall status of their disease. Intense radiation therapy can cause problems eighteen to twenty-four months after its administration, a consideration of importance if long-term survival is expected.
SUMMING UP
Brain tumors carry a number of problems that are not found in most other cancers. Since they affect our center of intelligence and emotions, most patients and their families are understandably reluctant to accept a diagnosis of brain tumors. In many instances a benign tumor can be just as serious as a cancerous one something that is not true with other types of cancer. Primary brain tumors are relatively rare, but the brain is a common site of metastases of cancers arising elsewhere in the body. Many of the symptoms of early brain tumors are subtle and may go unnoticed until there is a buildup of intracranial fluid and serious encroachment on vital brain structures. While most primary brain cancers are not curable, surgery usually can relieve symptoms and prolong life. Many benign tumors, if detected in an early stage, can be cured by surgical removal without causing major residual damage.
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