Melanoma, also known as malignant melanoma, is a type of malignant tumor that originates from melanocytes and is commonly found in the skin, as well as in the mucous membranes and the choroid of the eye. Melanoma is the most malignant type of skin tumor and is prone to distant metastasis. The clinical manifestations of melanoma include: morphological or color changes of existing skin pigmented nevi, bulges on the skin surface, itching of pigmented nevi, local bleeding and cracking of finger (toe) nails, etc. The early manifestation of pigmented nevus malignant change has the following five points: 1. Asymmetry: one half of the pigmented spot looks asymmetrical with the other half. 2. Irregular edges: the edges are irregular or have cut marks or jagged teeth, unlike normal pigmented nevi which have smooth round or oval outlines. 3. Color change: Normal pigmented nevus is usually monochromatic, while melanoma mainly shows dirty black, but it can also have many different colors such as brown, brown, brown-black, blue, pink, black or even white. 4.Diameter: Pay attention to pigmented spots with diameter >5~6mm or when the pigmented spots grow significantly, melanoma is usually larger than normal moles, so keep an eye on pigmented spots with diameter >5mm. It is better to do biopsy evaluation for pigmented nevi >1cm in diameter. 5. Bulging: In some early melanomas, there is a slight bulging of the entire tumor. The only shortcoming of the above five points is that it does not take into account the rate of melanoma progression, such as the tendency for significant changes to occur within a few weeks or months. Further progression of early cutaneous melanoma may present with satellite foci, ulcers, recurrent failure to heal, regional lymph node metastases, and metastatic metastases. Symptoms of advanced melanoma vary depending on the site of metastasis, with sites prone to metastasis being the lung, liver, bone, and brain. Melanoma of ocular and rectal origin is prone to liver metastases. Patients with metastatic melanoma may experience a range of nonspecific symptoms, including loss of appetite, nausea, vomiting, and malaise. In addition, melanoma metastases to different parts of the body may present with different symptoms, such as bone pain for bone metastases and cough and hemoptysis for lung metastases.