332 



\•l•:■|■|-:RI^^\R^• PATHurjitn*. 



toplasinic mass occur nlan^• small \'ari(iiish- sha])ed cells. lUood 

 cavities and canals are abundant and henn irrhai^ic areas are not 

 uncommon. 



TERATOMA. 



These tumors are composed of the different kinds of tissues that 

 approximate the structure and arrangement of normal tissue so 

 closeK that it is difficult to dift'erentiate them macrosopically or 

 microscopically from normal tissues and (jrgans. Teratomata 

 are so closely related pathcilogically to malformation, that in 

 some cases it is impossible to determine which condition exists. 

 Structurally they are found to be composed of either embryonic 

 or adult tissues. C'utaneous structures are the most fref|uent tis- 

 sues ofjseryed in this class of tumors, alth(iugh tissues of bone, 

 muscle, intestine, rudimentary- e}-es, brain, etc., haye been found 

 in them as well as sarcomatrius and carcinomatous tissue. 



Fig. ISl 



-l>erii»oi(l (>st 



ini lh(- witliers of a hors 



These tumurs are (piite \-ariabk" in size, sha]"!e and color. In 

 consistenc}-, they \-ar3' from a yiscid mass to dentine and enamel. 

 Tliey are usually single, grow slowly and rarely form metasta- 

 ses, although a few ha\e been nbseryed that grew rapidly, metas- 

 tasized and recurred when remo^•ed. They frecpiently undergo 

 degeneration tending tn cystic formation. Clinically, teratomata 

 are Ijenign, only rarely terminating fatal'-V. 



Eti(jlogically, they are as mysterious as the other tvpes of 

 tumors. They ma^' haye their origin from tissue inclusions. 

 Some teratomata may succeed imperfect tissue union. The the- 



