Pigmented nevi are the most common benign skin tumors that occur anywhere in the body and can appear at birth or early in life. Melanoma is caused by abnormal proliferation and malignant transformation of melanocytes, and can occur at any age. Early treatment is very important, otherwise it can be life-threatening. The appearance of the so-called melanoma in the fabricated plot of the movie “Misfits 2” has made many people panic about melanoma, causing many people to seek medical treatment blindly. On the other hand, due to improper handling of pigmented moles or insufficient attention, early melanoma delays diagnosis and loses the best chance of treatment. So how to self-assess whether a pigmented rash on the body is a mole or a melanoma? The first step is to learn how to determine the condition of the rash, and the early detection of melanoma can be based on the medical “ABCDE rule”. solid #000; “EN-US”>C refers to color variation. Normal pigmented nevi are usually a single color, while melanoma can show a variety of different colors such as brown, brown, brown-black, blue, pink, and black mixed together. D refers to Diameter, melanoma is usually larger than normal nevus, so it is important to pay attention to nevus with diameter >6mm; if the nevus is >1 cm, it is better to consult the doctor promptly. E refers to Evolving, which is a manifestation of the above-mentioned lesions developing. It should be noted that the presence of ABCD 4 manifestations at the same time should be taken seriously, or there is already ABCD, plus E. The presence of melanoma is usually highly suspected. Secondly, we should pay attention to the signs of malignant transformation of pigmented nevi, because more than 60% of melanomas are transformed from pigmented nevi. Signs that a pigmented nevus turns into a melanoma include the following: ① A recently appeared pigmented nevus in adulthood (usually over 35 years old); ② An existing nevus increases significantly within a short period of time (within one year), and its color deepens or its pigmentation becomes uneven; ③ The edge of a nevus becomes irregular, or even a small satellite nevus appears, or several nevi merge and the surface is uneven; ④ A pigmented nevus has crusts, ulcers, or bleeds easily when touched; ⑤ Painlessly enlarged lymph nodes are found near the pigmented nevus. If any of the above conditions occur, you should seek medical consultation promptly. Finally, we need to understand what factors affect the malignant transformation of pigmented nevus into melanoma. These factors mainly include irritation, friction, long-term sun exposure, improper medical treatment, etc. When pigmented nevi are subjected to repeated friction, scratching and trauma, benign pigmented nevi are easily transformed into malignant melanoma. Therefore, pigmented nevi that grow on the feet, hands (including palms and under the nails), genitals and other parts that are susceptible to friction and trauma should be given enough attention, especially those who are engaged in physical labor and even often barefoot are more likely to have pigmented nevi on the soles of their feet turned into melanoma. Therefore, it is recommended that moles growing on the palms of hands, soles of feet and external genitalia should be removed as early as possible and pathological examination should be done routinely. Pigmented nevi in exposed areas can also be affected by ultraviolet rays and undergo malignant transformation. Some beauty lovers choose laser, freezing and chemical erosion methods to spot moles, which can easily stimulate melanocytes and cause malignant changes due to incomplete removal, and this is a very dangerous treatment method. Some moles advertised on the telephone poles or chemically “spotted moles” on the street may not only induce malignant changes, but also leave scarring if not well mastered. With the above knowledge, it is easier to self-evaluate whether the pigmented mole is benign or malignant, and whether it needs preventive removal or can be kept for life.