CYSTS. 



Teratoma. 



307 



Teratomata are tumors of complex structure, sometimes 

 consisting of a mingling of several types of tissue as gland, 

 nervous, muscle, and connective tissue ; sometimes being com- 

 posed of more or less complete organs, as breasts, nerves, 



FIG. 136. 



Dermoid cyst of the ovary, showing all the structures of true skin except sweat- 

 glands viz., epithelium, rudimentary papillae, fibrous tissue or cutis vera, hair- 

 follicles, large sebaceous glands. X 18 (Boyd;. 



muscles, portions of intestine constituting so-called dermoid 

 tumors, which, however, usually present themselves as cysts 

 filled with hair, teeth, and occasionally bone, muscle- and 

 nerve-tissue. Teratomata also include certain malformations 

 and monstrosities (Fig. 136). 



CYSTS. 



A cyst is a cavity, usually with a distinct membranous wall, 

 which contains a fluid or semifluid material. They are not 

 really tumors, though usually considered in connection with 

 the latter. They are generally classified according to the 

 method of their formation. 



