Synovial sarcoma is a malignant tumor of soft tissue originating from the synovial membrane of joints, synovial membranes and tendon sheaths. The etiology and tissue origin are not clear. The large joints of the extremities are the preferred sites, but may also occur in the muscular membranes and fascia of the forearms, thighs, and low back. The main clinical symptoms are mainly local painless masses, and surgical resection is the most important treatment. I. What are the clinical manifestations of synovial sarcoma? Synovial sarcoma occurs in young adults aged 15-40 years, and often presents as a painless mass near the large joints of the extremities. Patients may develop periarticular swelling, and the mass may extend along the soft tissue to the entire limb. The duration of the disease varies, mostly 2-4 years, and is generally slow-growing. In the later stages, there may be venous anger and varying degrees of pain on the skin surface of the mass, and a few patients have limited local limb movement. Synovial sarcoma is a highly malignant tumor that can metastasize to regional lymph nodes as well as to distant lungs. What are the examination items of synovial sarcoma? 1.X-ray examination About 30% of the lesions can be seen as faint scattered calcifications, and sometimes periosteal reaction can be seen, or even erosion of bone or invasion of bone, which only appear as soft tissue masses at first, and later calcifications can appear in the masses. 2.Bone scan In the late stage of the scan, a limited increase in uptake around the mineralized active area of the lesion is seen. Due to the abundance of neovascularization in the lesion, the uptake in the lesion area is higher than that of the adjacent soft tissue in the early stage of the scan. 3.CT CT scan shows a soft tissue mass with uniform texture and density similar to skeletal muscle, and the calcification within the lesion is highly suggestive of synovial sarcoma. The edge of the mass is enhanced after contrast injection. 4, MRI The lesion is often adjacent to important neurovascular bundles and is high signal on MRI images. Larger lesions have heterogeneous signal intensity, suggesting areas of hemorrhage and necrosis, so these structures may be displaced or encapsulated in the lesion. 5. Angiography In the early arterial phase, significant neovascularization is seen in the reaction zone around the lesion, and in the late venous phase, significant staining is seen. How to differentiate and diagnose synovial sarcoma? Synovial sarcoma is usually found near the large joints of the extremities and is a malignant tumor. If the mass occurs around the joints, synovial sarcoma should be considered as a possibility, and local MRI and chest X-ray should be performed to clarify the local scope and general condition.