The osteogenic portions of the bone do not give rise to sarcoma of the true fibrospindle cell type, the connective tissue tumors arising in this structure being either fibroblasts of the fibro-osseous series with a tendency to true bone formation (fig. 1) or precartilaginous connective tissue destined to form bone via the intracartilaginous route (fig. 2) (Geschickter1). Fibrospindle cell sarcoma arising in either the outer layers of the periosteum or in the adjacent soft parts may, however, invade the osseous substance and give rise to a tumor in which the predominant manifestations on physical or roentgenologic examination are related to the bone. Such bone involvement, by direct extension from the soft parts, is clinically very confusing, particularly when the bone changes are extensive, and even at operation or after pathologic examination of the tissue, is usually misinterpreted as a primarily osseous lesion.
While from a pathologic standpoint this group