In 2001 by Feng Xiaogang, director of a New Year’s movie “Do not disturb” after the screening, dermatology outpatient clinics around the country suddenly increased a lot of patients, we are worried, to see whether the pigmented mole into the dreaded “malignant melanoma”, a period of time, almost “talk about moles color change! “In fact, the pigmented nevus is transformed into malignant melanoma. In fact, the number of patients whose pigmented nevi turn into malignant melanoma is extremely small. According to statistics, about 1/3 of melanoma is caused by malignant transformation of junctional nevus, in which the incidence rate of Caucasian people is higher, and there are about 2 cases of melanoma in every 100,000 people every year. As the saying goes, there are signs and symptoms before a nevus becomes malignant, which generally takes a few months to a few years. In our life, we should pay attention to observe the size, softness, color and hair growth of nevus, for example, we found that nevus in the near future 1, suddenly bulge and increase in size, asymmetric shape, irregular shape, uneven color, different shades; 2, the nevus suddenly become blacker, reddened, decoloration, hair loss; 3, bleeding, erosion, ulceration, scab, dander on the surface of the nevus, accompanied with burning, stinging, itchy, and painful to the touch, etc.; 4, The border of the mole is blurred, satellite-like small black spots appear around the mole and the lymph nodes around it are enlarged. As long as you have any of the above, you should be vigilant and go to the dermatology department of the hospital for examination in time.