326 TUMORS. 



CHONDROMA. 



These tumors, composed of either of the forms of cartilage, are usually 

 hard, but sometimes quite soft. The cells do not present the same uni- 

 formity in size, shape, number, and relative position that they do in nor- 

 mal cartilage (Fig. 170). Sometimes they are very large, spheroidal, and 

 grouped in masses, and again small and far apart. They are frequently 

 fusiform or branching. Fibrillar connective tissue in varying quantity 



FIG. 170. CHOXDROMA OF FEMUR. 



is usually present in the chondroniata, either as a capsule or running in 

 bands between the nodules of cartilage, or passing in fascicles into them. 

 The cartilage may change to mucous tissue, forming myxochondroma, 

 the cells may undergo fatty degeneration or they may calcify or ossify. 

 Chondroniata frequently form a part of mixed and complex tumors. 

 Metaplasia plays an important part in the development of cartilage 

 tumors of mixed type. 



They may form in connection with bone or cartilage, and are often 

 traceable to irregularities in foetal development. Or they may occur in 

 soft parts where cartilage is not normally present, as in the parotid, tes- 

 ticle, mamma, and ovaries, where they are apt to be mixed with other 

 tissue ; or in subcutaneous connective tissue and fasciae. 



They are in general benign tumors, but metastases sometimes occur, ' 

 most frequently in the lungs, sometimes in the heart. 



Small hyperplastic growths on the surfaces of cartilages are called 

 ecchondroses. 



OSTEOMA. 



The formation of .bone in the body in abnormal places occurs quite 

 frequently and under a great variety of conditions. It is on this account 

 not easy to define the term osteoma, and it is frequently difficult to de- 

 cide whether or not a given mass of new-formed bone should be thus 



1 For a study of metastases in chondroma see Ernst, Ziegler's Beitr., Bd. xxviii., p 

 255, 1900, bibl. 



