1. May occur at any age, adults common. 2. Main symptoms are pain and mass. Central intense pain, but early in peripheral mass. 3. Where the secondary, longer course, the early onset of symptoms is the main symptom. 4. Pathologic fracture - prone, especially central. 5. X-ray: central marrow cavity was uneven edge of the cystic destruction, cortical bone can be destroyed, but no periosteal reaction. Visibility larger peripheral soft tissue shadow of cortical bone destruction often confined to the side, the pressure was to trace marrow depression. When penetrated to the marrow when there will be the wormhole-like or irregular cystic bone defect.
