All physical things have a size. Sometimes we are feeling a lump or nodule with our hands, sometimes we are looking at something with a type of X-Ray. In oncologic discussion, either may be referred as a mass. Usually we are concerned about the presence of, it s size, or demonstation of local invasion. M elanocyte cells derived from the neural crest that are in the skin and produce the protein pigment, melanin.
Melanin is responsible for skin color.
Metastasis Malignant cells that have invaded normal tissue away from the start of origin. The cells travel via the lymph system or the vascular system and invade other organ systems. Another way of looking at the phenomena is indirect invasion or extension of the malignancy. Therefore, we have new growth. Anything neoplastic refers to new growth.