Mr. Li has a black mole that has been growing on the soles of his feet for many years. Someday, it suddenly changes, causing the mole to grow larger and protrude on the surface, which affects walking. Doctors found that it was malignant Melanoma through surgical biopsy, and secondary metastasis was also found in the lungs through systemic examination. Although Curative care, including surgical resection, Genetic testing, radiotherapy and chemotherapy, Mr. Li died six months later. This inconspicuous "mole" is not an ordinary mole, but a Melanoma. Melanoma is a malignant tumor originating from Chromatophore, which can be evolved from congenital or acquired benign Chromatophore nevus, or from malignant transformation of dysplastic nevus. It is most common in middle-aged and elderly people (the age with the largest number tends to be 50~69 years old). Although the incidence rate of Melanoma is not high, the malignancy is very high and the mortality rate is very high, because 59% of patients are in the middle and late stages of treatment, and the 5-year survival rate of patients with advanced Melanoma is only 5%~10%. According to the epidemiological survey, the incidence rate and predisposition of Melanoma in different countries and regions are different. In China, the common sites of Melanoma are extremities (including toes, fingers and fingernails, toenails or under nails) and mucous membranes (including rectum, anus, vulva, eyes, mouth, nose, throat, etc.). We should pay more attention to the changes in the "black mole" that occurs in these areas. When skin moles show the following changes, one should be vigilant: ① Half of the moles appear asymmetrical with the other half; ② Irregular edges, serrated or unclear boundaries; ③ The normal pigmented nevus is usually monochromatic, and Melanoma is mainly characterized by uneven and dirty black; ④ Black nevus diameter>5 millimeters; ⑤ The shape, size, and color of a mole change. Once the above five situations occur, we should seek medical attention in a timely manner, listen to the professional opinions of doctors, and achieve early detection and treatment. Zheng Rui (attending physician in dermatology department of the Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine) (Outlook New Times)