High grade surface osteosarcoma - A clinicopathologic study of 46 cases

BACKGROUND, High grade surface osteosarcoma is a rare subtype of osteosarco ma arising on the surface of bone, accounting far only 8.9% of surface oste osarcomas at the study institution. METHODS. This study reviews 46 cases of high grade surface osteosarcoma, co mprised of 13 cases from the Mayo Clinic files and 33 from the authors' fil es. Histologic features were reviewed in all cases, and radiographs were re viewed in 29 cases. RESULTS. There was a definite male predominance, and 70% of the patients we re in the second and third decades of life. Forty-four of the 46 patients h ad lesions involving the long bones, the mast common site being the midport ion of the femur. Radiographically, the majority of lesions showed dense to moderate mineralization with a fluffy, immature appearance. Radiating spic ules of bone perpendicular to the long axis of the bone, characteristic of periosteal osteosarcoma, were sparse. Histologic findings were identical to those of conventional osteosarcoma. Overall, survival at 5 years was 46.1% . Statistical analysis revealed that marginal excision was associated with an increased risk of local recurrence and that the patients with Broders Gr ade 3 tumors had a better prognosis than those with Grade 4 tumors. A good response to chemotherapy was associated with better clinical outcome. CONCLUSIONS. High grade surface osteosarcoma is a rare subtype of surface o steosarcoma that has a prognosis similar to that of conventional osteosarco ma, in contrast to the more common type of osteosarcoma arising on the surf ace of bone. Wide excision and effective systemic chemotherapy are associat ed with better clinical results. Cancer 1999;85:1044-54, (C) 1999 American Cancer Society.