Radiology of medullary chondrosarcoma: preoperative treatment planning.

We evaluated the radiologic studies of 30 medullary chondrosarcomas with respect to their accuracy in diagnosis and surgical staging. There were 30 sets of plain radiographs, 14 conventional tomograms, 26 radionuclide bone scans, 19 arteriograms, and 15 computed tomograms (CT). Plain radiographs provided most of the diagnostic information although many tumours looked benign. CT provided the most complete anatomic staging, including intra- and extraosseous tumor, and neurovascular involvement. However, it was difficult to be sure about subtle soft tissue invasion. Arteriography remained useful for evaluating major vessel involvement or cortical penetration when CT and conventional tomography were equivocal. Scintigrams disclosed increased uptake, usually corresponding to the true tumor extent; "extended uptake" beyond the tumor was uncommon. Conventional tomography has been largely replaced by CT, but was occasionally useful when the tumor was near the end of a bone.