Figure 10e. Conventional intramedullary chondrosarcoma of the tibia in a 60-year-old man. (a) Anteroposterior and lateral radiographs show an extensive diaphyseal tibial lesion that is predominantly lytic. Areas of chondroid matrix mineralization are seen superiorly (large arrow) and a focus of deep scalloping (small arrows), cortical remodeling, and periosteal reaction (arrowheads) anterolaterally. (b) Anterior bone scan reveals marked radionuclide uptake in the lesion greater than that in the anterior iliac spines. (c) Axial CT scan shows the deep endosteal scalloping, cortical breakthrough, soft-tissue extension (M), and central flocculent calcification (C). The nonmineralized component has low attenuation. (d) Axial gadolinium-enhanced T1-weighted (688/14) MR image with fat saturation reveals mild peripheral enhancement (arrows) with deep endosteal scalloping extending through the cortex with soft-tissue extension (M). (e) Coronal T2-weighted (3,426/60) fat saturation MR image shows lobular growth (arrows), cortical penetration with soft-tissue extension (M), and high signal intensity throughout the lesion. (f) Photograph of the coronally sectioned gross specimen reveals the deep endosteal scalloping (arrows) and soft-tissue extension (M), identically correlating to imaging features.