Sometimes we see patients with plantar malignant melanoma in outpatient clinics, who underwent amputation in local hospitals with incorrect treatment, but still metastasized to the root of the thigh; there are even patients who had their thighs and half of their buttocks amputated after lymphatic metastasis to the root of the thigh, and still metastasis occurred. Incorrect treatment not only fails to improve the treatment effect, but also causes disability to the patient and decreases the quality of life, which is very unfortunate. The following is the knowledge about malignant melanoma. Malignant melanoma Q&A: 1. Can a small mole become malignant? (Yes, sometimes a small mole can become malignant or even fatal!) 2.What kind of moles can become malignant? (Moles that are subject to friction: waist of pants, neckline, soles of feet, back of feet, toes, under the nail bed, eyelids, trunk, limbs, oral mucosa, etc.) Some moles that were asymptomatic at first but later have itching and stinging sensations; some moles have changed color from light to dark or become miscellaneous; some moles have gradually increased in size and have irregular edges, so we should be alert to the possibility of malignant change) 3. (Anti-friction, anti-exposure to sunlight, timely outpatient consultation for suspicious moles, removal and pathological examination, never throw them away without pathology. (And you should never think it is a corneal and take a knife to handle it by yourself.) 4.How to treat malignant melanoma? (Once the pathology is clear as malignant melanoma, surgery is the first choice and it is recommended to go to a specialist hospital for treatment. (For malignant melanoma originating from the extremities, surgical wide incision and skin implantation are preferred, without amputation.) (1) Surgical treatment. (The abdominal surgery department of Fudan University Cancer Hospital has admitted 750 cases of malignant melanoma patients in the past 40 years, which is the largest number of cases in this country. Our stage I has a 1-year survival rate of 99.3%, a 5-year survival rate of 81.6%, and a 10-year survival rate of 73.5%.) (2) Immunotherapy. This is the consensus of the three major clinical trials conducted worldwide. It improves survival rates. (Interferon a2b or interleukin-2 is recommended and needs to be used according to the patient’s blood routine liver and kidney function and under the guidance of a physician) (3) Radiation therapy. (Effective for some types of malignant melanoma) (4) Chemotherapy. If there is lymphatic metastasis, chemotherapy should be done under the guidance of a specialist (chemotherapy drugs for malignant melanoma are DTIC (azithromycin), DDP (cisplatin), TMZ (temozolomide), etc.). 5. What about lymph node metastasis? (Generally, the larger the lesion, the deeper the ulcer, the deeper the invasion of melanoma, the easier the lymph node metastasis. For patients with lymph node metastasis, inguinal or axillary lymph node dissection can be performed. Through surgery and post-operative chemotherapy and interferon treatment, some patients can survive for a long time. So how to know whether there is lymph node metastasis earlier? At present, Fudan University Cancer Hospital carries out anterior lymph node biopsy, according to the technique of nuclear scan lymph node visualization, the lymph nodes will be removed and biopsied, and then decide whether to perform lymph node dissection according to the intraoperative frozen pathology. (It is conducive to alleviate patient’s pain, reduce patients’ financial burden, reduce unnecessary complications and shorten hospitalization time.)