Plain radiograph (lateral view) of the knee joint in a 17 y/o female who presented with history of pain in her right knee (same case as the previous image). The findings are typical for an osteosarcoma. There is a destructive lesion with an admixture of lytic and sclerotic areas, elevation of periosteum by the proliferating tumor (Codman triangle), calcification of the tumor matrix, and a soft tissue mass. Case produced with permission, courtesy of Dr. Frank Gaillard. Radiopaedia. Complete case is here.