Figure 9e. Conventional intramedullary chondrosarcoma of the humerus in a 21-year-old man with shoulder pain. (a) Anteroposterior shoulder radiograph shows a proximal humeral mixed lytic and sclerotic lesion with expansile remodeling. The sclerotic component represents typical chondroid ring-and-arc calcification (white arrows). Lytic focus seen inferolaterally (black arrow) demonstrates deep endosteal scalloping typical of chondrosarcoma. (b) Anterior bone scan shows that the lesion has radionuclide uptake greater than that in the anterior iliac spines. (c) Axial CT scan shows decreased attenuation of the nonmineralized component of the lesion and chondroid mineralization (arrows). (d, e) Axial T1-weighted fat saturation (repetition time msec/echo time msec = 600/20) MR images obtained before (d) and after (e) intravenous administration of gadolinium show signal intensity similar to that of muscle and mild peripheral and septal enhancement (arrows). (f) Coronal T2-weighted (3,000/57) MR image demonstrates lobular growth (large arrow) and a focus of deep endosteal scalloping with cortical penetration (small arrows) laterally. (g) Photograph of the coronally sectioned gross specimen shows a cartilage lesion with lobular growth (large arrow) and cortical destruction laterally (small arrows), identically correlating to imaging features.