Actinic Keratosis
Also called solar keratosis. A non-malignant skin lesion which is red and scaly. Although an actinic keratosis is occasionally referred to as "premalignant", it rarely ever becomes a true malignant tumor.
Benign Tumor
A noncancerous growth that does not invade nearby tissue or spread to other parts of the body.
The removal and microscopic examination of tissue from the body for purposes of diagnosis.
A general term for many different diseases characterized by abnormal and uncontrolled growth of cells. The resulting mass, or malignant tumor, can invade and destroy surrounding normal tissues. In addition, certain types of cancer can spread (metastasize) through the blood to start new cancers in other parts of the body.
Malignant Tumor
Cancer. A growth of cancer cells (see definition of Cancer).
The spread of cancer through the blood or lymph vessels from one part of the body to another.
© Richard G. Bennett, M.D. 2003