Teenager with knee pain Pediatric Imaging Musculoskeletal August 28, 2026April 28, 2026 AP and lateral radiographs of the knee show in the posterior distal femur a lobulated, exophytic mass which appears attached to the underlying cortex with minimal periosteal reaction. The diagnosis was parosteal osteosarcoma. Related Published August 28, 2026April 28, 2026