Vascular endothelial cell tumors are malignant tumors that originate from vascular endothelial cells. They are generally classified into two grades according to their tumor histomorphology cell differentiation: one is intermediate type (low malignancy) with better cell differentiation and mostly no metastasis; the other is angiosarcoma with poor differentiation, high malignancy, high metastasis rate and high mortality. WHO statistics: intermediate type of hemangioendothelial cell tumor accounts for 0.28% of primary bone tumors and hemangiosarcoma accounts for 0.23%. Clinical manifestations The incidence has been reported in all age groups, but is mainly seen in middle-aged and young adults. The tumor can occur in all bones of the body, with long tubular bones being the most common. It is more common in the long bones of the lower extremities in multiple cases, especially in the right side. Clinically, patients often complain of swelling and pain in the affected limbs, and even limitation of joint movement. Tumors of the spine can also cause neurological symptoms. Once angiosarcoma develops, the disease develops rapidly, with local spread and blood metastasis in the late stage. On X-ray, intermediate hemangioendothelioma shows lamellar or irregular osteolytic swelling bone destruction in the long bone epiphysis with clear borders, involving cancellous bone and cortical bone. Residual bone trabeculae can be seen in the bone destruction area, and periosteal reaction is uncommon. In angiosarcoma, the bone destruction is patchy, foamy or large, with unclear borders, partial or complete loss of bone cortex, radiating bone pins in the adjacent area, and periosteal reaction, and sometimes soft tissue masses. Angiography can clearly show the intraosseous boundary and soft tissue boundary of the tumor. There are a large number of tortuous irregular tumor vessels arteriovenous fistulae within the tumor. The neoplastic disorganized vascular plexus is more common in angiosarcoma. Pathologic changes The tumor is soft with no envelope and filled with blood clots or spongy gelatinous blood clots. Microscopically, the tumor is seen to consist of proliferating capillaries. The vascular lumen is mostly immature, with anastomosis between vessels. The intermediate type of tumor vascular endothelial cells are still differentiated, round or oval, with deep stained nuclear Ontario, no or mild heterogeneity, and few splitting images. In angiosarcoma, a large number of new capillaries were seen microscopically. Endothelial cells were arranged in multiple layers and piles, with poorly differentiated cells, large dark-stained nuclei, and clear cytoplasm or fine granular material. The cells infiltrate into the mesenchyme, and bone trabeculae are difficult to see. Differential diagnosis It should be distinguished from osteolytic osteosarcoma, giant cell tumor of bone, chondrosarcoma, reticulocytic sarcoma and metastatic tumor. Treatment and prognosis The main treatment is surgery. Intermediate hemangioendothelial cell tumors occurring in the limb may be treated with extensive borderline resection of the tumor, autologous or allogeneic bone grafting, and appropriate internal fixation. In general, it seems that the five-year survival rate is 95-100% for grade I tumors and 60-70% for grade II tumors after complete surgical excision of the tumor. Multiple tumors can be treated according to the situation, and if necessary, amputation can be used. In case of recurrence, re-operation can be performed, and metastasis does not usually occur. Hemangiosarcoma, with high malignancy, rapid growth and involvement of soft tissues, is found to have metastases in many patients. Early stage cases can be treated with various effective limb preservation procedures, while late stage cases are treated with amputation or joint dissection, but the prognosis is generally very poor. The five-year survival rate is less than 20%. This type of tumor is more sensitive to radiotherapy and can be used as an adjuvant treatment before and after surgery. Radiotherapy in the vertebral body or pelvis is of greater significance, and there are reports of increased cure rates and improved quality of survival with radiotherapy-operation-radiotherapy.