The incidence of skin tumors has been increasing year by year in recent years, but like other tumors, many tumors of the skin, such as melanoma, basal cell carcinoma, and squamous epithelial cell carcinoma, evolve slowly from precancerous lesions, and one has enough time to recognize it before they eventually become tumors so that they can be nipped in the bud. A symptom common to all skin cancers is change, which is something everyone must be aware of. Here we will introduce several kinds of skin cancer: 1. Basal cell carcinoma and squamous cell carcinoma are usually asymptomatic, and the symptoms of early stage skin cancer are mostly manifested as the original swellings such as discoloration, skin redundancy and age warts gradually increase in size, harden, break down or bleed; some cancer swellings may be very tiny at the beginning, like the size of a needle point, and if left untreated, the cancer cells will spread to the surrounding tissues; once the cancer cells have spread Once the cancer cells have spread, it will be more difficult to treat. Typical symptoms of skin cancer may appear as wart-like elevation, and then break down into ulcer foci with irregular, elevated edges, resembling crater, and uneven bottom. 2.Sunburned skin may occasionally show flat, slightly red patches with scales, called actinic keratosis, which is not cancer, but may become cancer. 3.Malignant melanoma is the most dangerous type of skin cancer. Symptoms are usually the appearance of skin discoloration, color change of moles, appearance of new moles, and lesions involving cells that produce brown pigment and black pigment. Special attention should be paid to changes in dark skin spots, dots or moles, alerting to the formation of new moles, bleeding moles, changes in shape and color of old and new dark spots, and if any of the above symptoms are detected, medical attention should be sought immediately without delay. If treated early, malignant melanoma can often be cured; if ignored, the cancer cells will spread to other parts of the body and may invade various vital organs. Most skin cancers can be completely cured. The key lies in early diagnosis and treatment. Since skin cancer grows on the surface of the body, an experienced dermatologic surgeon can generally know whether a swelling on the skin is benign or not just by looking at it with his eyes. If he suspects skin cancer, he will cut off a small piece of tissue for pathological examination to determine whether the swelling is conscientious or malignant. If it is malignant, the dermatologic surgeon will choose one of many methods to remove the tumor. Even if the tumor is not cancerous, the surgeon may still remove the tumor to prevent it from becoming cancerous. Some precancerous skin lesions can be treated with a skin emulsion combined with an anti-cancer drug. For early-stage basal cell and squamous cell carcinomas, doctors may remove the tumor with a scalpel or with liquid nitrogen freezing. Cryotherapy uses low temperatures to kill the cancer cells and the wound heals in a few weeks. Doctors with experience in cosmetic surgery will treat the disease while considering the cosmetic results, and will use measures to prevent and treat scarring while treating the swelling. Malignant melanoma is potentially more dangerous than basal cell and squamous cell carcinoma, so the cancer is almost always surgically removed along with some of the surrounding tissue. If the cancer has spread to other parts of the body, it may have to be treated with other therapies, such as chemotherapy. Radiation therapy does not seem to be effective for this condition. The sooner you treat this condition, the better.