Soft tissue sarcoma of the limb is a rare clinical disease with an incidence rate of approximately 20 cases/1 million population/year, roughly twice that of osteosarcoma [1]. Soft tissue sarcoma of the thigh is the best site for soft tissue sarcoma. Soft tissue sarcoma of the thigh with huge volume is difficult to ensure a good extensive resection border because it is easy to injure the main vascular nerves and occur intraoperative hemorrhage, which leads to recurrence or metastasis within a short period of time after surgery and eventually has to be amputated. Since March 2000, our hospital has routinely performed MRI and DSA on 8 cases of giant soft tissue sarcoma of the thigh with initial or postoperative recurrence, and used a combined anterior-posterior approach and ligation of the deep femoral artery to perform extensive resection of the tumor. Data and methods Among the 8 cases in this group, 3 were male and 5 were female, age: 28-83 years old, average 45.5 years old. There were 3 cases of liposarcoma, 3 cases of malignant fibrous histiocytoma, 1 case of synovial sarcoma, and 1 case of fibrosarcoma, all of which occurred in the thigh, including 3 cases on the left side and 5 cases on the right side. The duration of the disease was 3-60 months, 3 cases were seen for the first time, 5 cases were recurred 1-60 months after surgery, and the number of recurrences was 1-7. One case of malignant fibrous histiocytoma underwent 7 local resections within 5 years at an outside hospital and recurred 3-12 months after surgery. All recurrence cases had no history of adjuvant therapy such as radiotherapy or chemotherapy between the first surgery and this admission. No distant metastases were found in all cases at the time of admission, and there was no femoral bone destruction. The size of all the cases in this group exceeded 15×10×10 cm by MRI measurement, and the largest one reached 29×16×14 cm. Treatment: After admission, patients underwent routine preoperative examination and X-ray, MRI and DSA examination to understand the tumor size, boundary, invasion range, blood supply and relationship with femoral vessels, and to assess the feasibility of local resection of the tumor for limb-preserving treatment. Routine preoperative preparation, preoperative indwelling catheter. The tumor was treated with continuous epidural anesthesia, and an oblique incision was made in the anterior medial thigh along the femoral artery, the length of which was comparable to the size of the tumor, but the proximal end had to exceed the tumor by 3-5 cm. The femoral artery was free and protected, and a cord was wrapped around the proximal femoral artery segment of the tumor for temporary blockage of the femoral artery to stop bleeding. The deep femoral artery was ligated when the DSA showed that it was the main nutrient vessel of the tumor. After initial confirmation of the extent and boundary of the tumor by palpation, the anteromedial margin of the tumor was separated by electric knife within the normal muscle at the periphery of the tumor, paying attention to preserve the quadriceps muscle as much as possible to maintain the knee extension power. The tumor is then placed in a lateral position with the affected limb on top, and a longitudinal incision is made on the posterior thigh to free and protect the sciatic nerve. If the tumor is adjacent to and compressing the sciatic nerve, the epineural membrane is carefully separated and excised together with the tumor, so as to ensure the extensive or partial border of tumor resection and minimize the chance of residual tumor cells. If there is more bleeding during the operation, the femoral artery can be temporarily blocked with a cord, but the blocking time should not exceed 45 minutes. Intraoperative blood loss was 350-1800 ml, mean 840 ml, transfusion was 0-1400 ml, mean 780 ml. Postoperative management: postoperative anterior and posterior lateral wounds were left with drainage tubes for 2-5 days, routine prophylactic anti-inflammatory, symptomatic and supportive treatment. Two of them had skin necrosis at the edge of the incision after surgery, one case was cured after 1 month of drug exchange, and one case was cured after local flap pushing 3 weeks after surgery. Four patients in this group started external radiation radiotherapy 3-5 weeks after surgery, and three cases had local recurrence within 1-2 years after surgery and again underwent extensive resection post-radiotherapy at a dose of 40-60 Gy. One case had no adjuvant treatment before and after surgery. One patient with postoperative recurrence of mucinous liposarcoma at the age of 69 years did not receive any adjuvant therapy after surgery, and requested for multiple local recurrences after surgery. The patient died 6 years later due to systemic failure, and no distant metastases to the lung or other sites were seen at the time of death. Discussion Malignant soft tissue tumors of the extremities can be commonly referred to as soft tissue sarcomas, and the more common ones in clinical practice are liposarcoma, malignant fibrous histiocytoma, synovial sarcoma, fibrosarcoma, smooth muscle sarcoma rhabdomyosarcoma and so on. Soft tissue sarcoma of the thigh is a common site of soft tissue sarcoma. Because of the abundance of soft tissues such as thigh muscles and fat, soft tissue tumors occurring in the deep part of the thigh are not easily detected in the early stage, and the pain of soft tissue sarcoma of the thigh is not serious in the early stage, so it is easy to be mistaken for muscle strain and delay the diagnosis and treatment. Some soft tissue sarcomas of thighs that were first treated in hospitals without tumor treatment conditions have recurred repeatedly due to incomplete surgery and irregular treatment, resulting in a wider and wider range of lesions and eventually forming huge soft tissue sarcomas. Soft tissue sarcoma often grows infiltratively along the tissue space without obvious envelope or only incomplete pseudo-envelope, and it is easy to invade around large blood vessels and nerves, so surgical excision is not easy to complete, resulting in recurrence or metastasis within a short period of time after surgery, and eventually amputation has to be performed. The resection boundary of soft tissue sarcoma is similar to that of malignant bone tumor, and can be divided into four resection margins: extended wide resection (radical resection), wide resection, marginal resection, and intra-focal resection. It is recognized by domestic and foreign scholars that good resection margins in the first surgery are decisive for controlling local recurrence after surgery [2 】 [3 】 [4 】 . Theoretically, the postoperative recurrence rate of intra-focal resection is 100%, and with the addition of adjuvant treatment such as postoperative radiotherapy and chemotherapy, the postoperative local recurrence rate is similar to that of margin resection. Extended wide resection means that the resection margin is more than 5 cm away from the tumor, or the whole tumor is completely removed beyond the tissue equivalent to this thickness [5]. Since soft tissue sarcoma of the limb mostly involves more than one interstitial compartment, to achieve the standard of extended wide excision, it is necessary to remove a certain muscle group of the limb or even including the main blood vessels and nerves, which will cause serious damage to the function of the limb or even make limb preservation difficult. Therefore, clinically, wide excision is more often used for limb preservation surgery of soft tissue sarcoma, while marginal excision can only be used for the side of the tumor adjacent to major blood vessels and nerves. Because of the deep location, wide range, rich blood supply, unclear boundary, no envelope or incomplete thin reactive pseudo-envelope, and easy to invade around large blood vessels and nerves, extensive resection should avoid damaging important blood vessels and nerves and keep the incision edge as far away from the tumor as possible to avoid tumor cell contamination of the incision due to tumor rupture. It is difficult to deal with the above two problems at the same time when using conventional single surgical incision. Moreover, because a tourniquet cannot be used during the operation, when there is a lot of bleeding and the operation field is unclear, it is easy to have the rupture of the tumor by passing the tumor at the edge of the incision, which eventually turns the wide resection into intra-focal resection and greatly increases the chance of tumor recurrence after the operation. In this group of cases, after careful preoperative study of X-ray, MRI and DSA imaging data to understand the tumor size, boundary, invasion range, blood supply and relationship with femoral vessels, extensive resection of huge tumor in thigh was performed by combined anterior-posterior approach, which better solved the intraoperative difficulties such as protection of vascular nerve, safe resection margin and intraoperative hemorrhage. According to the relationship between each branch of the femoral artery and the tumor shown by DSA, it was found that the nutrient vessels of the giant soft tissue sarcoma of the thigh were almost completely from the deep femoral artery and its branches. After ligating the deep femoral artery intraoperatively, the bleeding was significantly reduced during the separation and resection of the tumor, the operative field was clean and clear, and the operation was smooth. In addition, because the blood supply of the tumor was completely cut off, it was beneficial to reduce the local recurrence of the tumor. Since there are abundant traffic branches between the branch penetrating artery of deep femoral artery and the proximal superior gluteal artery, the distal uppermost knee artery and the muscular branch of N artery, the blood supply of femoral and thigh muscles will not be affected. However, there were two cases in this group with limited necrosis of the skin at the edge of the incision after surgery, which were cured by drug exchange and local nudging flap respectively, probably related to the large area of skin peeling from the incision. Local recurrence is a major complication after limb soft tissue sarcoma resection, and the local recurrence rate after wide excision is about 20% [5]. Tumor cells are left behind. Therefore, surgery alone cannot solve the problem of postoperative recurrence and distant metastasis, and a comprehensive treatment including surgery, radiotherapy and chemotherapy has become a recognized principle in the treatment of soft tissue sarcoma at home and abroad [2] [3] [4]. Clinical practice has demonstrated that the use of extensive resection and adjuvant treatment such as radiotherapy and chemotherapy for soft tissue sarcoma has achieved efficacy similar to that of high level amputation in the past [2]. Three cases in this group did not undergo radiotherapy and had local recurrence within 1-2 years after surgery, and then underwent wide excision and postoperative radiotherapy again, with no recurrence since the follow-up. one case did not undergo any postoperative adjuvant therapy and had multiple recurrences after surgery. This indicates that postoperative radiotherapy can effectively reduce the rate of local recurrence. For huge tumors with short course, rapid development and high malignancy, preoperative and postoperative high-dose chemotherapy should be given to prevent distant metastasis and create conditions for limb-preserving surgery. Typical case 1: male, 43 years old, giant malignant fibrous histiocytoma of the left thigh Preoperative MRI showed a giant soft tissue sarcoma of the left thigh Complete resection of the tumor by combined anterior and posterior approach