I. Overview Dermal aplastic fibrosarcoma was first described by Taylor in 1890. The histogenesis of this tumor has not been fully established, but it was previously considered to be a fibrous histiocytic tumor, and in 1995 Hugo concluded that cutaneous aplastic fibrosarcoma was derived from fibroblasts and myofibroblasts based on electron microscopic and immunohistochemical studies. It is now believed that the tumor is derived from primitive mesenchymal cells with multipotential differentiation and a genetic aspect of chromosome 22 in a circular pattern. The tumor occurs in the dermis, which is different from the general sarcoma, so it has the characteristics of skin tumor, showing subcutaneous nodular growth with slow and progressive growth, and the duration of the disease varies from a few months to 30 years, and the reason for the slow growth is still unknown. The tumor occurs mostly in the trunk and is prone to recurrence after surgery, and the recurrence is caused by incomplete excision for the first time. The size of tumor varies from 0.5cm to 12cm in diameter, with an average of 5cm, and the largest recurrence is 36cm. The number of recurrences can be as many as 10 times. However, metastasis is rare, so the survival rate is high, and there are even long-term survivors with tumors. Clinical treatment still advocates extensive resection and surgical repair such as skin graft and transfer flap. Radiotherapy can be considered as appropriate, chemotherapy is not effective. 2.Imaging Diagnostic imaging can also be applied. Since the lesions are often superficial, the appearance is easier to identify for easy diagnosis, but needs to be differentiated from keloid. 3.Pathological evaluation The tumor is solitary, nodular or lobulated, and elevated from the skin. The skin on the surface of the tumor is tense and small vascular bulges can be seen, sometimes forming ulcers. The tumor profile is grayish white and can invade the subcutaneous tissue, rarely invading the muscle. Some areas of the tumor may be mucous-like, but necrosis and hemorrhagic foci are rare. Histomorphologically, a large number of uniform and consistent fibroblasts were seen in the center of the tumor, surrounding the blood vessels and forming an obvious matted arrangement, with inconspicuous nuclear pleomorphism and visible nuclear division. Giant cells and yellow cells with a few inflammatory cells can be seen. Mucus-like sites were occasionally seen. In the superficial area around the tumor, small, spindle-shaped fibroblasts can be seen, much like the manifestation of fibrous histiocytoma. The main treatment for this tumor is surgery. Since the tumor is superficial and located in the skin layer, it is easy to be found, and the main emphasis is on the thoroughness of the first surgical treatment, and adjuvant radiotherapy and chemotherapy are not advocated. Reasonable radical surgery can achieve the purpose of radical treatment. Since this tumor is often classified as low grade malignant and prone to recurrence after local surgery, surgery should be performed with the goal of reducing recurrence rate. This tumor originates from the dermis of the skin and rarely invades deep muscles, so strictly speaking it should be classified as a skin tumor, therefore, the treatment is different from that of general soft tissue sarcoma. Therefore, the treatment is different from that of general soft tissue sarcoma. Surgical procedures should emphasize the removal of normal skin tissues including 3cm outside the skin margin, and subcutaneous and soft tissues as appropriate. Removal of normal skin 3cm away from the tumor can reduce the possibility of future recurrence. In recent years, there is a debate on the distance of tumor margin, but Parker et al. still emphasized that for tumors <2 cm, a margin of at least 2.5 cm is considered reliable. Therefore tumors over 3 cm in diameter still require a minimum margin of 3 cm. Since a circular or oval area of skin defect is often present in the surgical area after wide excision, skin grafting should be used. Reasonable extensive surgical excision and skin grafting is the right choice for the treatment of this tumor. If the area of defect is too large, repair with a vascular tipped insular muscle flap or fascial flap may also be considered. Random fasciocutaneous flaps are more convenient to apply and are more compatible with the surrounding normal tissues, so they can be used as much as possible. It is common to mistake benign tumor and perform minor surgery for local excision in outpatient clinic. The local excision of benign tumor is often left behind to cause future recurrence. In fact, this is not a real tumor recurrence, but a residual tumor caused by the surgeon's insufficient resection margin. The time to supplement extensive resection after local excision should be within 1 month after surgery, and no later than 3 months. The tumor grows slowly and is not easily metastasized. Even if the local tumor remains and then supplemented with extensive resection, the tumor still has no recurrence and metastasis and survives for a long time. If the tumor is locally resected for more than 3 months, close follow-up observation will be considered and radical resection will be performed when there are signs of recurrence. There has been a debate on whether radiotherapy should be applied to cutaneous augmentation fibrosarcoma. suit 1996 reported 15 cases of combined surgical and radiotherapy with a 10-year control rate of 84%, and the 3 cases that failed were within the group of 12 cases with positive cut margins. Therefore, it is still necessary to ensure negative surgical margins. In case of positive margins and those who are not suitable for further surgery because they are located in the trunk, etc., postoperative supplemental radiotherapy can be considered. It is generally believed that a radiation dose of 50-60Gy can prevent recurrence. Recurrent tumors should be treated actively and can still be cured after extensive resection and repair at the original recurrence site again. It means that even if the tumor recurs, it can still survive for a long time after reasonable treatment.