Extraskeletal masses are chondrosarcomas. Central chondrosarcoma is a chondrosarcoma that originates from within the bone. The main symptom is deep pain that is not intense and non-persistent. In the progressive stage of the tumor, large spherical extraosseous masses may form. There are distinct sites of predilection, in order of predilection, for the femur (especially proximal), pelvis, proximal humerus, scapula, and proximal tibia. The other bones of the trunk, the radius, the ulna, the foot, and the hand are the less frequent sites of softness (chondromas are common in the hand and less common in the trunk bones). Precautions to prevent extraosseous masses: 1. Patients with chondrosarcoma may feel discomfort in the affected area in the early stage, and swelling and masses may appear after a few days or weeks. In general, patients with chondrosarcoma will feel pain around the joints, initially intermittent pain, which gradually worsens after a period of time and turns into persistent pain, more obvious at night, and ineffective in taking painkillers. 3. Patients with chondrosarcoma have limited joint movement, and some patients may experience joint effusion or even pathological fracture.