SPONTAXEOUS NEOPLASMS IX MICE 



207 



Osteogenic sarcoma. — This is a malignant tumor of bone origin (Fig. 

 115). Primary tumors in the bone would include those originating from 

 osteogenic tissue and those arising from the bone marrow cells. In this 

 section we will consider only those which develop from osteogenic tissue and 

 which retain, more or less, the ability to form bone. The myelocytomas or 

 bone marrow tumors are considered in the section on the tumors of the blood 

 forming and blood destroying tissues. 



We have not found a large number of osteogenic sarcomas in our labora- 

 tory. However, they have occurred in scattered body regions including the 

 skull, jaw, humerus, ribs, pelvis, femur and tail vertebrae. The stocks 



■Osteogenic spindle- 

 shaped cells 



\ H 



fc ^^ >: I '^Tt^r^^'lrr il4 U.^g;*ajMrr-^Newly formed bone 



Fig. 115. — Osteogenic sarcoma from a rib (X200). 



showing most of these osteogenic sarcomas have been the yellow, the C57 

 black, dba, X, Danforth's posterior duplication and Zavadskaia's brachyury. 

 Hybrids of some of these stocks with other lines have also developed 

 osteogenic sarcoma. 



Pybus and Miller (45), on the other hand, were able to derive sublines of 

 the Simpson strain of mice that develop a high incidence of spontaneous bone 

 tumors. These developed at about sixteen months of age and originated in 

 the skull, jaw, fore and hind limbs, ribs, sternum, pelvis and spine, most 

 often in the last named site. Among the early reports on bone tumors were 

 those by Ehrlich (10), Haaland (22), and J. A. Murray (43). 



These tumors may develop as compact, rapidly growing, spindle-shaped 

 cells resembling tibrosarcoma. However, most of these tumors retain their 

 bone forming potentiality and show varying amounts of cartilage and bone 

 in all stages of development. Cartilage may or may not be found, and 

 frequently the tumors show foci of branching and anastomosing bony 

 trabeculae. Surrounding the bone and cartilage are interlacing strands of 



