One hundred thirty patients with histologically verified primary fibrosarcoma of bone, unassociated with any pre-existent benign bone condition, were treated at Memorial Sloan-Kettering Cancer Center between 1918 and 1973. This series of cases represents approximately 5% of primary malignant bone tumors treated in our institution. Eighty-nine of the lesions were medullary or central in location, and 41 were periosteal or peripheral. There was a nearly equal sex distribution, and a mean age of 38 years ranging from 4 to 83 years. This lesion exhibited a strong predilection for long bones, with the most common location being the femur (43 cases), humerus (16 cases), and tibia (12 cases). In 19 instances, bones of the head and neck area were the primary sites. The roentgenographic differential diagnoses included os- teolytic osteogenic sarcoma, malignant giant cell tumor, metastatic carcinoma, or solitary plasma cell myeloma. Major ablative surgery was the primary method of therapy. Amputation was performed, yielding the best curative results in high-grade tumors, while radical local excision sufficed for most low-grade periosteal fibrosarcomas. Thirty-four percent of the patients survived 5 years (27% medullary and 52% periosteal), while 28% were alive after 10 years (20% medullary and 48% periosteal). These survival rates provide further evidence that fibrosarcoma of bone is a distinct clinicopathologic entity and not a variant of osteosarcoma, which carries a much poorer 5-year survival rate of approximately 17%. & M a 35:837-847, 1975.
IBROSARCOMA OF BONE IS A MALIGNANT
F fibroblastic tumor, characterized by interlacing bundles of collagen fibers lacking any tendency to form tumor bone, osteoid, or cartilage, either in its primary site or in its metastases. It is one of the least common of the primary malignant tumors of bone, and only represents approximately 5% of such neoplasms treated at this institution.
In the past, some authors denied the existence of a fibrosarcoma arising in bane and contended that such lesions were undifferentiated osteogenic or chondrosarcoma. Others questioned the actual occurrence of primary medullary fibrosarcomas, since it was believed that these were secondary to the