Chondrosarcoma. Unlike osteosarcoma, chondrosarcoma is a disease of older bones (patients are nearly always over 40). The typical appearance of chondrosarcoma is a lytic lesion with stippled calcification within it, as shown in the radiograph here. The mass has destroyed the anterior cortex of the distal femur (arrows). MRI (right-hand image) is routinely performed for assessment of primary bone tumours, as it better delineates the local extent of the lesion, and can show skip metastases elsewhere in the same bone (most common in osteosarcoma).