306 \I'.TF,RtNARV PATHOLOGY. 



group into large and small-celled varieties. The cells are usu- 

 ally held together by reticular connective tissue. This ma}- be 

 demonstrated in sections in which the sarcoma cells have been 

 dissohed out 1)v acetic acid. The density of the tumor depends 

 upon the relative quantity of protoplasm the cells contain and 

 the amount of intercellular material. A tumor composed of 

 short, thick spindles is less dense than one composed of fibi-e- 

 like cells. Blood vessels usually have normal vessel walls and 

 are not as numerous as the\' arc in round-cell sarcomata. 





a 









>^.^j^a f ©ir^-- ^ ^- s">j ®>;^A - %'^ 



evMj 



Fi-4 1^1 — ,M>eliitl or (Jiant cell Sarcoma <»f the Ulinieru*. 



;i <;i;int r lis Ij, saminia cells. 



These tumnrs are usuall\- enca])sulated, rarel}^ form metas- 

 tases and are, in general, not as malignant as the round-cell 

 variety. They may l)e mistaken for fibromata, l)ut a careful 

 study of a microsci qjic sectiim is usually sufficient for difTeren- 

 tiatiou. Fi]:>riimata cmitain Ud elements that appear like trans- 

 \-erse sections (if spindle cells. Leinmyoma may be differen- 

 tiated by the sliapc nf the nucleus and the selectixx- action of 

 stain as picn ifuclisin. 



Myeloid-Cell Sarcoma (Giant-Cell Sarcoma). — This is a 

 variety nf sarcoma characterized by the presence of myeloid or 

 large multinucleated giant cells f myehiplaxes). Surgeons and 

 ]iathologists frequently find myeloid sarcomata in man, but they 

 are rare in domestic animals. They are invariably found in 

 relation to, or in connection with, bone-marrow, or more rarelv 



