Figure 1. Proximal humeral anteroposterior (AP) pseudocyst in a 22-year-old man. This AP radiograph of the shoulder shows the typical trabecular rarefaction of a humeral pseudocyst in the region of the greater tuberosity (arrows).
Figure 2. Anterior calcaneal pseudocyst in a 25-year-old man. The typical trabecular rarefaction of a pseudocyst can be seen in the anterior calcaneus (white arrows) on this lateral radiograph. Incidental bone islands are present in the talus (black arrows).
Figure 3. Vertebral body hemangioma in a 48-year-old woman. (A) The vertically oriented, thickened trabeculae (corduroy sign) of a vertebral body hemangioma can be seen on this lateral view, which is coned down to the L2 vertebral body. (B) T1- weighted and (C) T2-weighted MR images show the typical increased signal intensity of a vertebral body hemangioma (arrows). (D) This axial CT image of the L2 vertebral body illustrates the classic dot appearance to the trabecular bone found in vertebral body hemangiomas.
Figure 4. Simple bone cyst in an 8-year-old child. This anteroposterior radiograph of the proximal humerus shows the fallen fragment sign (arrow) of a simple bone cyst.
Figure 5. Intraosseous ganglion cyst in a 16-year-old. This axial CT image shows intralesional gas (arrow), which confirms the diagnosis of an intraosseous ganglion cyst in this otherwise healthy patient.
Figure 6. Paget's disease involving the calcaneus in a 50-year-old man. (A) This lateral radiograph of the ankle readily shows the classic Paget's disease findings of an enlarged bone, coarsened trabeculae (arrows), and thickened cortex (arrowheads). (B) This coronal T1-weighted MR image of the calcaneus also shows the coarsened trabeculae (arrow) and thickened cortex (arrowheads) of Paget's disease. In the peripheral skeleton, bone involved with Paget's disease should have normal marrow signal interspersed between the coarsened trabeculae.
Figure 7. Enchondroma of the proximal phalanx in a 57-yearold woman. The pathognomonic findings of a lytic geographic lesion with expansion and chondroid matrix (arrows) are seen on this radiograph of the proximal phalanx of the index finger.
Figure 8. Langerhan's cell histiocytosis involving the spine in an 8-year-old boy. In this otherwise healthy child, vertebra plana can be seen (arrow) in the thoracic spine, which is consistent with Langerhan's cell histiocytosis.
Figure 9. Intraosseous lipoma of the calcaneus in a 35-year-old man. (A) This lateral radiograph of the ankle shows a geographic lytic lesion in the calcaneus. Dystrophic calcifications, known as the cockade sign, can be seen within the lesion (arrow). This is a classic pathognomonic appearance and location of an intraosseous lipoma. Parasagittal (B) T1- weighted and (C) Short tau inversion recovery (STIR) MR images, respectively, show signal characteristics (hyperintense on T1 and hypointense on STIR) that are consistent with a fatcontaining lesion (intraosseous lipoma). Signal arising from the dystrophic calcifications can also be seen within the lesion (arrows).
Figure 10. Enchondroma of the distal femur in a 45-year-old woman. This anteroposterior radiograph of the distal femur readily shows the coarse dot-like, popcorn-like mineralization of chondroid matrix.
Figure 11. Osteosarcoma of the proximal tibia in a 14-year-old girl. The wispy, cloudlike mineralization (arrows) of osteoid matrix can be seen on this anteroposterior radiograph of the proximal tibia.
Figure 12. Nonossifying fibroma of the distal tibia in a 9-year-old girl. The classic circumscribed edge of a geographic lesion is seen on this anteroposterior radiograph of the distal tibia. The lesion has sclerotic margins with minimal cortical expansion, making this a grade IA lesion.
Figure 13. Typical appearance of a grade III lesion. (A) Metastasis in a 35-year-old woman. This anteroposterior (AP) radiograph of the ilium shows the typical diffuse, ill-defined appearance of permeative destruction. (B) Multiple myeloma in a 57-year-old woman. This AP radiograph of the ilium reveals the classic moth-hole appearance (arrows) of moth-eaten destruction.
Figure 14. Typical appearance of a grade II lesion. This anteroposterior radiograph of the tibia shows the combined geographic (arrows) and moth-eaten destruction (arrowheads) of a grade II lesion. Grade II lesions can also have a combination of geographic and permeative destruction.
Figure 15. Example of a grade IC lytic lesion: an aneurysmal bone cyst in a 10- year-old boy. This anteroposterior radiograph of the humerus shows a lesion that is primarily geographic; however, there is a region where the cortex becomes ill-defined, making this a grade IC lesion (arrow).
Figure 16. Example of a grade IB lesion: an aneurysmal bone cyst in a 14-year-old girl. This anteroposterior radiograph of the proximal fibula shows a geographic lesion with >1 cm expansion of the cortical shell (arrowheads). This degree of expansion makes this a grade IB lesion.
Figure 17. Osteosarcoma in a 13-year-old girl. (A) This anteroposterior radiograph of the right shoulder shows a pathologic fracture through an osteosarcoma of the proximal humerus. Osteoid matrix can be faintly seen in the soft tissues (arrows). (B) Parasagittal T1-weighted and (C) postgadolinium T1-weighted images show the primary lesion in the proximal humerus as well as a skip lesion in the distal humerus (arrows). Normal intervening marrow can be seen (arrowheads).
Figure 18. Chrondroblastoma in a 16-year-old girl. (A) An anteroposterior radiograph of the distal femur showing a grade IA lytic lesion containing possible chondroid matrix. (B) An axial CT image of the same lesion readily shows the coarse dot-like, popcorn-like mineralization of chondroid matrix.