There are more or less some moles in human body, and many people are used to them in daily life, and even call the moles that grow between the beauty bows as “beauty moles”; some people often use laser surgery to remove moles because too many moles on their bodies affect their beauty; some people worry that the hard nodes formed after trauma to hands and feet will become cancerous. Some of these people often use scissors and blades to flatten them, etc. A small percentage of these people will suffer from malignant tumor – melanoma, which is what we call malignant melanoma. The incidence of this disease is relatively high in Europe and the United States, while the incidence in China is relatively low, only 0.8/100,000, but in recent years, due to air pollution and other factors, resulting in its incidence is on the rise, but due to the lack of awareness of its seriousness among doctors and patients, it is usually too late when it is diagnosed, coupled with the treatment is not standardized, the effect of melanoma treatment is extremely unsatisfactory. Therefore, it should be given enough attention. What is malignant melanoma? Melanoma, is a malignant tumor originating from melanocytes, which are differentiated from melanocytes of neural tube pluripotent stem cells. In humans, melanocytes are located at the junction of the epidermis and dermis of the skin. Unlike other epidermal cells, melanocytes rarely proliferate under physiological conditions, and their survival, migration, and differentiation are regulated by specific genes and a series of molecules expressed on their own and neighboring cell surfaces and in the extracellular matrix. Most believe that when environmental factors cause an imbalance in these genes and molecular regulation, melanocytes become malignant and become malignant melanoma, or malignant black. The malignancy of these tumors is high, with cutaneous malignant melanoma accounting for only 4% of all malignancies originating in the skin, but its lethality rate is 79%. It is prone to distant metastasis and has a poor prognosis. Why do people get malignant melanoma? Most of the malignant melanoma occurs due to the malignant transformation of benign nevi into malignant melanoma caused by repeated rubbing and scratching, inappropriate excavation and drug erosion, etc. It is reported that 84% of malignant melanoma comes from benign nevi, because the nevi are relatively small at the beginning of the disease, many patients do not notice some subtle changes in the nevi at the beginning of the disease. People who work outdoors and receive more ultraviolet rays are prone to malignant melanoma of the skin. In addition, the incidence of melanoma is higher in people who live in places with serious environmental pollution. In terms of age, melanoma mostly occurs in middle-aged and elderly people, and very rarely occurs before puberty. In addition, women during pregnancy or childbearing age can cause malignant melanoma to develop rapidly suggesting that the disease is endocrine related. What should be done to prevent malignant melanoma? Perform regular self-examinations of the skin. Avoiding sun exposure as much as possible and using a sunshade are important primary prevention measures. Increase education for the general public and professionals, especially for those at high risk. It is more important to improve the “three early stages”: early detection, early diagnosis and early treatment. For pigmented nevi that occur in areas prone to friction, biopsies should be taken for pathological examination. For example, children with large hairy nevi in the waist, which are often rubbed and squeezed by the belt, should be removed as early as possible. If it is difficult to remove all of them at once, the main part of the nevus can be removed in the middle of the nevus before it becomes malignant, and then both sides can be sutured. After the skin around the service is pulled loose, the rest of the mole can be removed until all of it is removed. In order to prevent malignant change, each excised specimen must be sent to pathological examination, and if there is malignant change, all of them should be excised, and then implantation should be performed. It is not advisable to stimulate the nevus with needle picking, corrosive drugs or thorough freezing and laser, which are dangerous methods. This is because nevi often become malignant due to traumatic stimulation. It has been reported that malignant changes occurred due to incomplete freezing at one time. In addition, malignant melanoma is also associated with external stimulation. If the mole is removed for cosmetic reasons, it should be removed in one go. Freezing combined with excision is aimed to be done at one time. Split excision is not recommended, and the excised specimen should be sent for pathological examination.