ANGEIOSARCOMATA. 297 



of sarcoma vary ; they may be such as to suggest the term 

 fibrosarcoma, myxosarcoma, chondrosarcoma, etc. 



Giant-celled or myeloid sarcomata are characterized by the 

 presence of large, flat, irregularly shaped, multinucleated cells, 



FIG. 126. 



Giant-celled sarcoma of the superior maxilla : epulis. a, large giant-cell, with numer- 

 ous nuclei ; b, tangential section of a similar cell. Aside from the giant-cells, 

 the growth is composed of spindle-cells and a moderate amount of a fibrous in- 

 tercellular substance. The tumor was removed from a man forty-one years of 

 age, and was of slow growth, having attained the size of a filbert in two and a 

 half years (Dunham). 



and arise most frequently from the marrow or periosteum 

 of bone (Fig. 126). They are of slow growth and less 

 malignant than the other varieties, though metastasis may 

 occur. 



Alveolar sarcoma is a very malignant variety, which bears a 

 close resemblance to cancer in that the cells are arranged in 

 an alveolar fibrous stroma. The cells, however, are not of an 

 epithelial type, and are separated from each other by fine tra- 

 becula? extending in from the alveolar walls (Fig. 127). They 

 are most frequent in the skin, occurring also in lymphatic 

 glands and serous membranes. 



Angeiosarcomata arise from the adventitia of bloodvessels, 

 which are surrounded by the masses of proliferating round 



