TUMORS. 367 



of the vessels. The cellular bundles may not all lie parallel to 

 each other, but frequently are interwoven, so that a given section 

 will contain longitudinal, cross, and oblique sections of the indi- 

 vidual cells. Such appearances must not be mistaken for the some- 

 what similar aspect of sections of mixed-cell sarcomata. 



The spindle-cell sarcomata are among the most common of tu- 

 mors. They may arise from any of the connective tissues. When 

 they spring from the periosteum they are apt to have an imper- 

 fectly formed bony tissue associated with the structure of the sar- 



FIG. 330. 



Spindle-cell sarcoma. (Riudfleisch.) Where the cells of the tumor lie parallel to the 

 plane of the section their spindle shape is manifest ; where they are perpendicular to 

 the plane of the section their cross-sections appear round. The bloodvessels appear to 

 have no proper walls, but to be bounded by the tissue of the neoplasm. 



coma. They then form osteosarcomata or osteoid sarcomata, accord- 

 ing to the perfection with which the structure of normal bone is 

 reproduced. 



In judging of the probable malignancy of a given specimen of 

 spindle-cell sarcoma, the rapidity of its growth, as evidenced by 

 the number of mitotic figures seen in the cells, and the abundance 

 of fibrous intercellular substance, must be taken into consideration. 

 As a group, the spindle-cell sarcomata are less malignant than 

 the small round-cell sarcomata ; but this is because the majority 

 of spindle-cell sarcomata have a well-marked intercellular sub- 

 stance of fibrous character. Those forms which are almost desti- 

 tute of this are hardly less malignant than the small round-cell 

 variety (Figs. 331 and 332). 



e. GIANT-CELL, SARCOMA. This form of sarcoma is charac- 

 terized by the presence of large, multinucleated cells lying among 

 the other cells of the growth. These giant-cells may be scattered 



