Usually melanomas are larger than 5 millimeters. Melanoma is generally referred to as malignant melanoma, which is a highly malignant cancer that occurs mainly in the skin. Most melanomas are transformed from normal pigmented nevi, but there is a clear difference between melanoma and pigmented nevi in terms of clinical manifestations. Melanoma tumor lesions are extremely irregular and asymmetric, the edges of the lesions are rough, easily adhered to the surrounding normal skin tissues, and the boundaries are not clear, and the color of melanoma is mostly a mixture of black and brown, and the tumor is prone to grow rapidly in a short period of time, making its diameter more than 5 mm. Patients with symptoms of melanoma are recommended to go to regular hospitals and be treated under the guidance of doctors to avoid delay.