Teenager with back pain AP and lateral radiographs of the lumbar spine taken during a CT myelogram show loss of height of the L3 vertebral body and sclerosis of its posterior elements. Axial CT myelogram through the L3 vertebral body shows lytic lesions in the vertebral body and an expansile sclerotic appearance of the posterior elements with periosteal reaction. The diagnosis was osteosarcoma of the spine.