A
tumor is a mass of new tissue
that grows within the body and has no physiological use. As
the tumor grows, it may press upon or even dislodge nearby
organs, and may "steal" oxygen and other nutrients needed
by those organs. "Benign" tumors are those tumors that are
not likely to recur after removal; "malignant" tumors are
those that are likely to recur and progress, often posing
a threat to life. Even benign tumors can be serious, since
if they cannot be removed by surgery, they will continue to
grow.
The brain is the second most common site
of tumors (the uterus is first). Brain tumors are especially
serious in a number of ways. First, the brain is enclosed
within the confines of the skull. As a tumor grows and presses
on surrounding tissues, the brain tissue will become compressed,
leading to dysfunction. Second, as a tumor grows, it may destroy
normal brain cells and take their place, interfering with
the brain processes normally served by those neurons.
Finally, brain tumors are often very difficult to remove,
since they may be buried under brain tissue; this may make
the tumors inaccessible to a surgeon without risk of severe
brain damage to the patient.
by Catherine E. Myers. Copyright © 2006 Memory Loss and the Brain |
