The changes seen in neoplasm are heritable in that these characteristics are passed on from each cell to ots offspring, or daughter cells. Neoplasm occurs only in muticellular organisms. The main classification of the neoplasms as either benign or malignant relates to their behavior. Several relative differences classify these two classes. A benign neoplasm, for instance, is harmless, but malignant is not.
Malignancies grow more rapidly than do benign forms and invade adjacent normal tissues.
Tissue of a benign tumor is structured in a manner similar to that of the tissue from which it is derived, malignant tissue, however, has an abnormal and unstructured appearance. Most malignant tumors, in fact, exhibit abnormalities in chromosome structure, that is, the structure of the DNA molecules that constitute the genetic materials duplicated and passed on to later generations of cells. Most important, however, benign neoplasms do not begin to grow at sites other than the point of origin, whereas malignant tumors do. Thus a scar, an abcess , and a healing bone callus are all designated as tumors, but they are not neoplasms. Besides being classified according to their behavior, neoplasms can also be classified according to the tissue from which they arose, and they are usually designated by a tissue-type prefix.