School ager with knee pain

Radiograph of telangiectatic osteosarcoma of femur
AP (left) and lateral (right) radiographs of the knee show a metaphyseal lesion that is lytic in appearance with an osseous matrix and a wide zone of transition and a Codman’s triangle of periosteal reaction with associated cortical destruction. On the lateral image there is a suggestion of an associated soft tissue mass posteriorly.

The diagnosis was telangiectatic osteosarcoma.