Pathology of osteosarcoma.

Osteosarcoma of bone is a tumor composed of malignant cells that produce osteoid. Some tumors show predominant chondroid or fibromatoid ground substance. All, however, are highly malignant and about 80 per cent produce death with metastases. The roentgenogram affords important evidence for the correct diagnosis of many of them. Differential diagnosis should include consideration of those sarcomas with many benign giant cells and the group of "telangiectatic" osteosarcomas that may contain only small diagnostic areas. Malignant fibrous histiocytoma is now considered as a possible diagnosis for some malignant bone tumors, but the exact criteria for the diagnosis of this condition are still somewhat obscure. Newer modalities of adjunctive treatment, such as resection of pulmonary metastases, chemotherapy, and immunotherapy, give promise of improving the prognosis for osteosarcoma.