It is cancer of cartilage cells. More than 40% of adult bone cancer is chondrosarcoma, making it the most prevalent bone cancer in adults. The average age of diagnosis is 51, and 70% of cases are in patients over 40. Chondrosarcoma tends to be diagnosed at an early stage and often is low grade. Many chondrosarcoma tumors are benign (not cancer). Tumors can develop anywhere in the body where there is cartilage, especially the pelvis, leg or arm.