Malignant melanocytoma is a malignant change from the melanocytes in our body’s skin, and can occur on any piece of skin throughout the body, like a mole. Since the airing of “Do Not Disturb”, many people have become concerned about the pigmented moles on their bodies, fearing that they are malignant melanomas. Since melanoma is painless and itchy, most patients are not in the early stages of the disease when it is detected, so self-examination is quite important. Is there any way to determine whether a mole is benign or malignant? Generally speaking, people can do self-checking at home according to the four criteria of “ABCD”. 1.Asymmetry(Asymmetry)，the left and right sides of the mole look different. It is irregular in shape and size. Border: The edge of the mole is irregular, such as protruding or sunken. 3.Color(color)，the color of malignant nevus is not uniform and varied. For example, black, brown and coffee color are interspersed. 4.Diameter(size)，the diameter of nevus is more than 6 millimeters, and the development is also quite fast. Since melanin tumor is found on the soles of the feet and palms of the hands of oriental people, if a person’s soles of the feet or palms of the hands appear uneven or uneven melanin mass, it should be paid special attention to; in addition, if any one of the nevus has itchy, bleeding, ulcers or pain, etc., it should be directly to find a dermatologist for further confirmation, regular observation or arrange for a skin slice examination, so as to avoid delaying the condition and missing the best time for treatment. The following is a list of the most common moles in the world