Objective To study the clinical characteristics,pathological type,diagnosis,treatment and follow-up result of the primary tumors of the sacrum.Methods The cases of 18 patients with primary tumors of the sacrum were treated by operation(12 cases with chordoma,1 case with osteosarcoma,5 cases with giant cell tumor of bone),patients with chordoma performed by radiotherapy after operation,and all patients had been followed up for 4~8 years.Results 15 patients were cured and 3 patients were recurred after operat...