Figure 4b. (a) Radiograph of the left hip demonstrates a periacetabular lytic lesion with a suggestion of punctate chondroid calcifications (arrow). (b) CT scan of the pelvis shows an expansile soft-tissue mass in the left ilium (arrowheads) and helps confirm the presence of chondroid matrix in the bone and mass (arrows). The cortical destruction and the size of the mass are indicative of a high-grade chondrosarcoma.