A mole growing up is not necessarily cancerous, some moles themselves may simply become larger with time, and if there are undesirable symptoms and changes, there is also the possibility of malignancy, and the specific reasons are analyzed as follows: 1. Pigmented moles are generally benign, and it is also called melanocytic nevus or nevus cell nevus, of which the common types are intradermal nevus, compound nevus and junctional nevus. Usually malignant nevus is developed from pigmented nevus, but pigmented nevus and malignant melanoma are different in general and microscopic performance, first of all, malignant melanoma grows faster, the boundary is not clear, the pigment on the surface is uneven, the color is blackened and deepened, and there can be ulcers, necrosis, bleeding and other changes or some small tumors grow around the mass, like satellites, in this In this case, it cannot be treated by general surgery and may be malignant melanoma, especially moles in special areas, which need patients’ high attention and should be removed, such as moles on hands, feet and genital area, which can easily become malignant if they are subjected to frequent friction; 2. Especially if the size of pigmented mole diameter exceeds 0.6cm, it must be removed as early as possible to prevent malignant transformation. Malignant melanoma has a very high degree of malignancy and must be closely monitored.