Definitions of osteosarcoma, chondrosarcoma, and fibrosarcoma of bone.

The current definition of osteosarcoma, based on the prescence of tumor osteoid, is unsatisfactory because it fails to identify some examples of chondroblastic, fibroblastic, and anaplastic osteosarcoma having no demonstrable tumor osteoid. The tumor cells in osteosarcoma, whether osteoblastic, chondroblastic, fibroblastic, or anaplastic, contain abundant alkaline phsophatase, whereas this enzyme is scanty or absent in condrosarcoma and fibrosarcoma. It is therefore proposed that these bone sarcomas are best defined according to the origin of the constituent tumor cells and their alkaline phosphatase content: osteosarcoma--a malignant tumor of osteoblasts (alkaline phosphatase positive); chondrosarcoma--a malignant tumor of chondroblasts (alkaline phosphatase negative); and fibrosarcoma--a malignant tumor of fibroblasts (alkaline phosphatase negative).