It is often said that a tree lives on a piece of bark and a person lives on a breath. It is clear that the bark of a tree plays an extremely important role in maintaining the survival of the tree. For humans, the skin also has the same important role. The skin is the largest organ of the human body, accounting for 16% of the individual’s body weight, and the total area of the skin of an adult is about 1.5m2. It covers the surface of the body and plays an important function as the boundary between the internal and external environment of the body. The skin originates from the ectoderm and mesoderm, and its tissue structure is exceptionally complex. Under the action of various pathogenic factors, all kinds of skin tissues can proliferate abnormally and form tumors, so the types of skin tumors far exceed those of other organs. Skin tumors can be divided into two categories, benign and malignant: [common benign skin tumors] epidermal nevus; sebaceous nevus; congenital hemangioma; keloid; seborrheic keratosis. Common malignant skin tumors: Bowen’s disease, also known as in situ squamous cell carcinoma; Paget’s disease, also known as eczema-like carcinoma; basal cell carcinoma (BCC); squamous cell carcinoma (SCC); malignant melanoma (MM). Some benign skin tumors also have a tendency to become malignant, especially those located in exposed areas of the head and face, and in areas that are easily irritated by friction. When the following signs appear on the surface of the body, it is recommended to seek medical consultation and surgical excision if necessary: 1. sudden increase in the size of the swelling; 2. local itching and discomfort; 3. darkening of the swelling with uneven pigmentation; 4. surface erosion, bleeding, ulceration, repeated crusting, not easy to heal; 5. satellite lesions appearing in the surrounding area, etc.