Skin malignant tumors, like other tumors, also have primary and secondary, clinically, primary is more common, secondary is rare, and the more common ones in primary are basal cell carcinoma, squamous cell carcinoma, carcinoma in situ, eczema-like carcinoma and so on. The incidence rate of domestic skin malignant tumors (except malignant melanoma) is about 1-2/10000, but there seems to be an increasing trend in recent years. Wang Shaohua, Department of Aesthetic Plastic Surgery, Weifang People’s Hospital Skin cancer generally has the characteristics of low malignancy, slow development, not easy to occur distant metastasis, easy to find and convenient biopsy, easy to make early diagnosis and early treatment, so the prognosis is good. Common types of skin cancer: Basal cell carcinoma: also known as basal cell epithelioma and erosive ulcer. Metastasis is rare. It is generally divided into four types, and the most common one is nodular ulcer type. (1) Nodular ulcer type: at the beginning, there is a small nodule on the skin, or it only seems to be erythema without significant elevation, or it is slightly nodular, and the skin on the surface is mildly sunken downward. The nodule may gradually expand or the center of the crust, followed by the occurrence of ulcers under the crust. (2) Pigmented type: the damage is the same as nodular ulcer type. It contains more pigment and is similar to malignant melanoma, which is easily misdiagnosed. (3)Sclerotic or fibrotic type: common in the head and neck, it is hard yellowish or yellowish white plaque, slightly elevated, with unclear boundary, like scleroderma, which can remain intact for a long time, and finally ulceration occurs. (4) superficial type: superficial lesions, mostly occurring on the trunk, presenting a piece or several pieces of infiltrative erythema, the surface of the flaking or crust, the edge or the whole lesion is slightly elevated. It is similar to eczema or seborrheic dermatitis. Squamous cell carcinoma: It is also called echinococcal carcinoma and epidermoid carcinoma. There is no obvious difference in clinical manifestations between early stage and basal cell carcinoma. However, squamous cell carcinoma mostly occurs in the skin with long-term abnormal state, which is often transformed from keratosis pilaris, mucous membrane leukoplakia or other precancerous diseases. The initial skin damage tends to be a dry, such as small papules or nodules, with a dull red surface, rough and uneven, and a tightly adherent keratinous material in the center, which is not easy to be peeled off, and after peeling off, it will grow keratinous material again. Later, ulcers may occur in the center, and the ulcerated surface is increasing, and its development is faster than that of basal cell carcinoma. Some of them resemble volcanic vents, with abnormal odor and conscious pain, and some squamous cell carcinomas develop outwardly, with the appearance of cauliflower pattern. The disease develops faster and is destructive, and can reach into connective tissues, cartilage, periosteum and bones, and regional lymph node metastasis can often occur, and visceral metastasis can occur in the late stage. Especially squamous cell carcinoma of mucous membrane is often easy to metastasize. Carcinoma in situ: also known as Bowen’s disease, is a kind of intraepidermal squamous cell carcinoma, which is considered to be a precancerous lesion of poor keratinization. Carcinoma in situ generally refers to atypical hyperplasia (severe) within the epithelium of mucosa or epidermis of the skin involving the entire epithelium, but has not yet invaded the basement membrane and infiltrated downward. Examples include carcinoma in situ of the cervix, esophagus, and skin. Even less infiltration and distant metastasis have occurred. However, it may further develop into early invasive carcinoma, and occasionally carcinoma in situ may regress. Although the extent of carcinoma in situ is limited, it may be multifocal or involve a large area without penetrating the basement membrane. Because carcinoma in situ does not form infiltration and metastasis, it does not conform to the characteristics of cancer, so it is not a real “cancer”. If it can be detected in time, resected as early as possible or given other appropriate treatments, it can be completely cured. Eczema-like epithelial carcinoma: also known as Paget’s disease (Paget’s disease), which often invades unilateral nipple and areola of women over 40 years old. The damage often starts from the nipple, mostly unilateral, and is limited crimson infiltration, the surface is easy to be eroded, and eczema-like changes are presented after scratching. It is usually slow, gradually expanding, and may invade all breasts to the chest wall. The nipple is enlarged and protruding, and there are hard nodules of chicken egg size in the breast. The lesions may also invade the skin outside the breast, such as the vulva, perianal area, armpits, face, lips, nose and other places. It may metastasize to nearby lymph nodes and internal organs. The epidermal changes of extra-breast paget disease are the same as that of the breast, but the ducts of sweat glands or sebaceous glands of hair follicles are often invaded by paget cells, and most of them have adenocarcinoma of sweat glands or are accompanied by adenocarcinoma of mucous membranes, squamous carcinoma, or carcinomas of internal organs. Confirmation of Skin Cancer Skin cancer in early stages or in some patients behaves similarly to many benign lesions, and the best way to confirm the diagnosis is surgery + pathologic diagnosis, i.e. skin biopsy. Skin cancer should be identified with what diseases? Clinical manifestations are similar to 1. Seborrheic keratosis, also known as senile warts, which occurs in men over 50 years old, mostly on face, neck, chest, back and back of hands, and the damages are round or ovoid flat wart-like rashes slightly higher than the skin, which are yellowish, yellowish-brown to coal-black in color, and the surface is slightly rough, and covered with greasy scales and crusts. 2, discoid lupus erythematosus: mostly seen in middle-aged men and women, the damage at the beginning of small papules, gradually expanding plaques, dry nature, surface keratin proliferation, follicular expansion, containing keratin embolism, with atrophic spots, do not form ulcers, the edge of the more congested. Keratoacanthoma: it is more common in middle-aged men, mostly occurring in the face, especially in the cheek and nose, and it is extremely rare in the limbs and trunk. The damage is a solid hemispherical tumor towering on the skin, which seems like light red acne or small knots similar to the skin color, and the central depression is crater-shaped, containing a horny scab. 4. Metastatic skin cancer: metastasized from primary cancer of other organs to the skin, generally multiple, with symptoms and signs of primary cancer of other organs at the same time. Pigmented basal cell carcinoma should be differentiated from melanoma. Surgery is the first choice of treatment for skin cancer, and the cure rate of appropriate surgical excision can reach 90%~100%. When excision is performed, basal cell carcinoma should be about 0.5cm away from the tumor, and squamous cell carcinoma should be about 0.5-1cm away from the tumor for skin incision, and sufficient depth is needed to perform extensive excision as far as possible. For confirmed regional lymph node metastasis, lymph node dissection should be performed, but prophylactic dissection is not necessary. Amputation is required when bone or major blood vessels and nerves are involved. After resection, direct suture or flap repair or implementation of skin grafting can be performed. Second, radiation therapy General squamous cell carcinoma is moderately sensitive to radiation, basal cell carcinoma is particularly sensitive to radiation and has higher skin tolerance. Radiotherapy can be mainly applied to skin cancer in special parts which are not suitable for surgery, old age and frailty, and those who have contraindications to surgery (diabetes, kidney, heart disease, etc.). Chemotherapy For patients who have undergone surgery to enlarge resection or radiotherapy, most of them do not need systemic chemotherapy. Systemic chemotherapy for skin cancer patients is mainly applicable to advanced cases which are not suitable for surgical resection or radiotherapy; patients who are still suspected to have residual lesions and metastasis after surgery and/or radiotherapy. Prognosis of skin cancer patients As skin cancer is mostly limited and located on the body surface, it is easy to be detected, with no or few metastases, if treatment is timely, most of them do not affect life; even if a few patients have local recurrence or multiple recurrences, they can still be surgically resected again, and most of them will still have good results; as simple surgical resection can achieve a cure rate of more than 90%, postoperative radiotherapy or chemotherapy is not usually carried out; radiotherapy or chemotherapy is only used for those who have not been cleanly resected or have metastases. Radiotherapy or chemotherapy is only used for those with unclean or metastatic local excision. Preventive measures of skin cancer 1. Avoid excessive sunlight or exposure in daily life, and avoid excessive exposure to ultraviolet rays and x-rays, etc. 2. Avoid prolonged contact with coal tar, arsenic and chemical carcinogens, and those who have occupational contact should strengthen protection and take regular checkups. 3.We should be alert to the long-term recurrence of ulcers, inflammation and mucous membrane white spots, long time not cured wounds, etc., and have regular checkups, and biopsy or surgical resection if necessary to avoid delaying the treatment. 4, suspected of malignant changes, skin biopsy should be performed as early as possible, so as to achieve early detection and early treatment.