What we usually call “nevus” is in fact not equal to benign melanocytic tumor, because many black lesions on the skin may be mistakenly called “nevus”, such as naevus, seborrheic keratosis, senile naevus, solar keratosis, basal cell carcinoma, fatal melanoma and so on. Some are very difficult to distinguish from “nevi”. Some are so difficult to distinguish from moles that even the most experienced dermatologists can still make mistakes. Moles have a very low rate of malignancy and are generally not a cause for concern. If treatment is needed, it should be surgically removed and pathologically examined, but not frozen, laser, drug corrosion and other treatments. The reasons are: 1, surgical excision recovery, no scar, good cosmetic effect; and laser, freezing and other damage to the surrounding normal skin, slow recovery, often leave scars. 2, freezing, laser, drug corrosion and other treatments are often incomplete, not removed from the mole cells can be due to stimulation of malignant changes. 3.After surgical excision, pathological examination can be done to make clear diagnosis, if found problems can be remedied in time, while freezing, laser, drug corrosion and so on can not achieve this purpose. 4.Early malignant melanoma looks like “black mole” to the naked eye, and pathological examination after surgical excision can make clear diagnosis and take remedial measures. Some moles such as nevus of Ota (greenish-brown spot around the eyes), nevus of Ito, etc. almost do not undergo malignant change, modern Q-switch laser can make it completely cured without damaging the normal skin, which is one of the most important progresses of modern laser medicine. In addition, some 2~3 millimeters big black spots are common in the face and various parts of the body surface, which are generally called “nevus”, and the correct name is “nevus”, and this kind of black spots can be completely removed by laser and drug corrosion without any concern. How to prevent melanoma? 1. Pay attention to moles on your body, especially congenital moles. If the nevus increases significantly after puberty, or there is a raised papule on a flat black spot, or the nevus is painful and uncomfortable, or the pigment deepens obviously, or there is a red halo around the nevus, it may be a sign of malignant change of the nevus. 2, pay attention to the nail black line. Some of them are nail moles. If a naevus appears after the age of 30, and the pathology report shows “melanocytic hyperplasia”, you must pay attention to it: the possibility of melanoma is very high! 3. Pay attention to the new black spots, especially the black spots on the soles of the feet. Black spots on the soles of the feet are painless and harmless, but in fact, they are often the most dangerous “terrorists”. In addition, after the age of 30, new moles rarely appear (many “moles” are actually seborrheic keratosis, commonly known as senile warts). If a new mole occurs and its size exceeds 0.5 centimeters, special attention should be paid to it, and it is important to go to a major hospital to find an experienced dermatologist to diagnose it, so as to exclude melanoma. In short, as long as we are vigilant, malignant melanoma of the skin can be nipped in the bud and not lead to serious consequences.