A, benign tumors 1, skin papillomas including squamous epithelial hyperplasia, papillary warts and age-related pigmented warts. Squamous epithelial hyperplasia: the formation of papillary protrusions on the skin surface, easy to find. Easy to become skin cancer. Treatment: surgical excision is the mainstay, or freezing or electrodesiccation can be done. Papillary warts: non-genuine tumors, mostly caused by viruses. The surface is papillary and outwardly protruding, see multiple fine columnar protrusions. Sometimes they can fall off on their own. Treatment: CO2 laser. The most important thing is that it is not a good idea to use a CO2 laser. The surface is dry, smooth or rough, but if the lesion is enlarged, elevated, bleeding or broken, there is a possibility of malignant transformation into basal cell carcinoma, but the malignancy rate is not high. Treatment method: It can be observed on follow-up, or surgically removed. 2.Nevus includes intradermal nevus, junctional nevus and mixed nevus. When the nevus pigment deepens and increases, or when there is itching and pain, it may be malignant; if there is rupture and bleeding, you should be alert and seek medical consultation in time. Treatment: Intradermal nevus can be treated without any treatment, while junctional nevus and mixed nevus should be removed surgically. 3.Lipoma originates from adipose tissue and is usually found on the extremities and trunk. They are soft in texture, have clear borders when touched, may have pseudo-envelope, grow slowly, and are mostly painless. Most of them are solitary, but in a few patients with multiple lipomas at the same time, most of them are small in size, usually symmetrical, with family history and painful. Examination: Ultrasound is an option to assist in the diagnosis. Surgery is often required to remove them. 4.Fibroma Fibro-yellow tumor: Mostly found in the trunk near the shoulder. It is often caused by the development of small papules after unaware of trauma or itching, and is dark brown in color. A biopsy of the mass may be performed to determine its nature, and subsequent treatment options will be made based on the pathological findings. Banded fibroma: located in the abdominal wall, it is a traumatic or postpartum repair fibroma of the abdominal muscle, often interspersed with hyperplastic transverse muscle fibers, and is not a true tumor. Diagnosis is difficult and ultrasound, CT or MR may be chosen to determine the depth and extent. Surgical treatment is the mainstay and should be complete excision. Neurofibromas: These include nerve sheath tumors and neurofibromas, which can occur at the nerve endings or anywhere along the nerve trunk. They can be solitary or multiple and can be huge in size. The former can be seen in the distribution locations of the nerve trunks of the extremities and is divided into central and marginal types, while the latter can be mixed with fat and capillaries and is multiple and usually symmetrical. Treatment: Surgical treatment is the only way. Neurofibromatosis, unlike neurofibromatosis, patients often have coffee-like pigmentation of the skin, the lumps may be breast-like, and may be associated with mental retardation, or unexplained headaches and dizziness, and may have a familial tendency. If the tumor is huge and sagging, it can be reduced by surgery. 5. Hemangiomas and vascular malformations Most hemangiomas have four characteristics, namely, rapid proliferation after birth, common in female infants, spontaneous ulceration, and self-resolution. Stages of hemangioma: proliferative, stable and regressive stages. In view of the natural course of hemangioma, it is still a very reasonable principle to actively inhibit its development during the proliferative phase and wait for it to recede on its own later. The common types of hemangiomas are wine stains, venous malformations and arteriovenous malformations. Wine stains, also known as erythema, have an incidence of 0.3% and are common congenital capillary and microvenous malformations. Venous malformations, formerly known as cavernous hemangiomas, are low-flow vascular malformations. Arteriovenous malformation, which used to be called trabecular hemangioma, originates from the abnormal vascular mass formed during embryonic period, and the incidence of extracranial arteriovenous malformation is 1/20 of intracranial incidence. Examination of hemangioma: ultrasound, puncture, MR, and DSA can be chosen for severe arteriovenous traffic. treatment of hemangioma: oral prednisone tablets, laser, injection, surgical excision. 6.Cystic tumors and cysts Cystic cysts, in fact, are a kind of cystic teratoma, which occurs in early childhood or adolescence and grows slowly. Cysts are round and spherical, not easy to push, mostly soft and fluctuating, a few more solid. The superficial ones are usually found at the brow tips and skull sutures. Ultrasound and CT can be used to determine if there is intracranial traffic. Surgery is the mainstay of treatment. Sebaceous cysts, also known as powdery tumors, are not true tumors and are very common. They are retention cysts formed by obstruction of sebaceous gland excretion, mostly on the head, face and back, and are sometimes seen as small black spots formed by obstruction of sebaceous gland openings. The cyst is a greasy, bean-like substance formed by the collection of keratinized material, which is prone to secondary infection and is accompanied by a strange odor. Many patients will use their hands to repeatedly squeeze out the stuff inside the lump a shrink the lump, but this method cannot cure it, or need surgical treatment. If there are already signs of infection such as redness and swelling, local fever, etc., you should take medication to control the infection before surgery. Epidermoid cysts, also known as epithelioid cysts, are caused by trauma that causes the epidermis to enter the subcutaneous tissue and continue to grow under the skin. They occur in areas that are susceptible to trauma or abrasion, such as the buttocks and elbows, or at the site of an injection. It is relatively easy to diagnose and also requires surgical treatment. Tendon sheath or synovial cysts, which are not true tumors, are caused by superficial bursae through chronic strain, mostly found near the wrist, dorsalis pedis tendons or joints, and are hard to the touch. Ultrasound can be used to assist in the diagnosis, and the treatment mostly adopts puncture injection or surgical excision, but it is easy to recur after treatment. Malignant tumor 1.Basal cell carcinoma belongs to low grade malignant tumor. It often occurs in the epidermal base cells or skin adnexa in hairy areas, characterized by slow growth and very little metastasis. The surface of the mass can be accompanied by bleeding, ulceration and odor. Surgery to expand excision is the best treatment method, which can also be supplemented by radiation therapy. 2.Squamous cell carcinoma is a tumor occurring in the epidermis or horn cells of the appendages, which is of low malignancy. It is related to sunlight exposure. However, early ulcers can be formed with irregularly elevated margins, and there can be local infiltration or regional lymph node metastasis. Surgical treatment is the main approach, with an extended excision including at least 2 cm of normal tissue around the tumor with sufficient depth. Radiation therapy can shrink the mass but cannot cure it radically. 3.Melanoma originates from skin melanocytes. Most of them come from malignant transformation of pigmented nevus. It has high malignancy, rapid growth and early metastasis. Once clearly diagnosed, surgical excision is the best treatment method. At the same time, it can be supplemented with immunotherapy. 4.Augmented dermatofibrosarcoma is mostly found in the trunk, with a raised surface resembling a scar. The growth is slow and the malignancy is low. The recurrence rate is very high when the mass is removed alone or small extended resection, and multiple recurrences can increase the malignancy and appear hematogenous metastasis. Therefore, surgical excision must include 4~5cm of normal skin around the tumor and sufficient deep fascial tissue.