Most of the malignant melanomas occur due to the malignant transformation of benign pigmented nevi into malignant melanomas caused by repeated rubbing, scratching and damage. In particular, many people do not pay enough attention to the nevi that grow on the feet, palms, genitalia and other friction-prone areas, so that they are squeezed for a long time and eventually undergo malignant transformation. People who are exposed to the sun for a long time should also pay attention. Early symptoms of melanoma 1. melanin deposition. Black deepening, followed by lesion damage expanding, increasing hardness, accompanied by itching and painful feeling. 2.Nodules. Some of the lesions of melanoma are raised, plaque and nodular, and some are myxoid or cauliflower-shaped. If the lesions grow into the subcutaneous tissues, they appear as subcutaneous nodules or masses, and if they spread in all directions, they appear as stellate black spots or small nodules. 3.Pigmented nevus. Most malignant melanomas originate from melanocytes in normal skin. Malignant melanomas are rare in children, but can originate from very large pigmented nevi that are present at birth. 4. Halo nevus. Usually disappear on their own but in rare cases they become melanomas. Although pregnancy predisposes to melanoma, pregnancy does not increase the likelihood of malignant transformation of a nevus into a melanoma. It is during pregnancy that the shape and size of the mole changes. The following red flags indicate malignant pigmented nevi: changes in size and color, reddening, blueness, especially the spread of hyperpigmented areas to the surrounding normal skin; inflammatory reactions in the skin surrounding the nevus, which may manifest as bleeding, ulcers, itching or pain; changes in surface features, changes in texture and shape.