Tumor (definition of)

The word tumor is usually associated with cancer, however the term refers to any abnormal growth, whether malignant or benign. The main difference is that while a malignant tumor, like mesothelioma, can grow and metastasize (spread) and even return once it is removed, the benign tumor does not. The latter however can become malignant if not removed, or may be an indication of a malignancy elsewhere.