In the present study we report two cases of secondary chondrosarcoma arising from osteochondroma. The first case was a 54-year-old male who had a large mass in the right pelvis, which arose from multiple osteochondroma. The second case was a 34-year-old male who had a cartilaginous mass arising from solitary osteochondroma of distal fibula. Radiological examination showed irregular calcification and thick caltilaginous cap in both cases. The secondary chondrosarcoma arising from solitary osteochodroma such as in the second case, is extremely rare. There has been only one previous report of a case in which secondary chondrosarcoma arose at distal fibula. In the present two cases, we resected the two tumors by wide margin. The clinical course of these patients was good and they returned to their jobs.
