surgically. Because of this, the malignant tumor tends to recur and tends to metastisize
or spread via the blood and lymph vessels. The common term for malignant tumors is
cancer. The medical profession speaks of carcinoma when the malignant tumor arises
from tissue that covers the surface of the body, lines a hollow structure, or forms glands,
and sarcoma when the malignant tumor arises from any other tissue in the body such
as fatty, muscular, bony, or fibrous tissue.
j. Idiopathic (Unknown) Causes. There are many diseases of unknown
etiology. The affected organ and effective treatment are often known, however, even
though the cause and the mechanism through which the disease disrupts the body's
functions remain unknown.