Sarcomas of bone in childhood: pathologic aspects.

Some sarcomas of bone are not characteristically childhood tumors. Within the context of osteosarcomas, telangiectatic and parosteal (juxtacortical) variants deserve recognition. Among chondrosarcomas, which ordinarily are not tumors that occur in children, the mesenchymal variant should be recognized in children especially, this lesion may be extraosseous. Fibrous histiocytoma and its malignant variant have recently emerged as morphologically specific lesions, occasionally osseous, among other spindle cell tumors. Ewing's sarcoma, which is predominantly of osseous origin, consists of undifferentiated fragile cells. The elaborate spectrum of topographic, cytologic, nuclear, and other morphologic features that fall within the designation Ewing's sarcoma are described.