Figure 41-2 ▪ This anteroposterior (AP) radiograph of the distal forearm and wrist show a radiolucent lesion which enlarges the bone and destroys the cortex laterally but is still contained by a periosteal shell of bone. It is epiphyseal in a skeletally mature individual and has the typical appearance of a giant cell tumor of bone since the growth plates are closed. It also shows a lesion that is intermediate in the Mankin score: it is somewhat large and the cortex is destroyed, but there is no soft tissue mass and it has some margination. If this were a purely epiphyseal lesion in a patient with open growth plates, chondroblastoma would be more likely. Note that a chondroblastoma usually starts in the epiphysis but may enlarge into the metaphysis, but a giant cell tumor if it presents in a younger patient begins in the metaphysis and extends to involve the epiphysis. (Courtesy of Children’s Orthopaedic Surgery Foundation.)

Figure 41-3 ▪ The anteroposterior (AP) radiograph shows the typical findings of a malignant bone tumor, in this case an osteosarcoma of the distal femur. The radiograph shows a poorly marginated, radiodense lesion of the distal femoral metaphysis in a skeletally immature female patient. It is large, destroys the lateral cortex, and has an associated soft tissue mass laterally (all 4 Mankin characteristics of a malignant bone tumor). (Courtesy of Children’s Orthopaedic Surgery Foundation.)

Figure 41-4 ▪ This radiograph shows an aggressive, “permeative” lesion of the diaphysis and proximal metaphysis of the left humerus. It is large and poorly marginated and displays “onion skin” periosteal elevation characteristic of a malignant bone tumor. It “percolates” between existing vascular channels of the cortex and the trabecular bone (better seen on histology) giving it the permeative appearance. Although the bone appears somewhat denser than normal, that is likely reactive bone and this proved to be an Ewing sarcoma, not a bone-producing sarcoma. (Courtesy of Children’s Orthopaedic Surgery Foundation.)

Figure 41-5 ▪ (A) Radiograph of the proximal femur in a patient with pain relieved with aspirin/nonsteroidal anti-inflammatory drugs (NSAIDs) and no history of trauma or fever. The thick, mature reactive host bone which has a smooth lobular outer contour is seen, but no lesion is appreciated. The maturity of the periosteal reaction suggests a long-standing, nonaggressive tumor. The appearance and history are suggestive of osteoid osteoma. (B) Axial computed tomographic (CT) image revealing the osteoid osteoma “nidus.” The actual tumor is this small rounded area with central immature matrix which on histology would show woven bone. The surrounding, more mature, and homogeneous periosteal bone is the host response to the osteoid osteoma and is part of the host reaction, not the tumor. Treatment of the central “nidus” with a radiofrequency ablation usually leads to pain relief and treatment for the tumor. (Courtesy of Children’s Orthopaedic Surgery Foundation.)