348 



TUMOBS. 



stomach, liver, thyroid, salivary, and prostate glands, in the pancreas, 

 kidney, testicle, and ovary, and may occur elsewhere. 



Gelatinous Carcinoma. The cells of certain carcinomata, especially of 

 the gastro-intestinal canal, may develop a translucent gelatinous material 

 whose nature is not well understood, which accumulates within the cells. ' 

 In some cases this accumulation is moderate when the protoplasm of the 

 cells may be more or less encroached upon by the translucent droplets of 

 the gelatinous material ; but in other cases, over large areas the cells are 

 partially or entirely destroyed, and replaced by the new material so that 



FIG. 200. CARCINOMA GKLATINOSUM "COLLOID CAXCKR." 

 From a tumor of the stomach. 



the alveoli of the tumor are distended by it, and their walls appear very 

 distinct in the midst of the gelatinous substance (Fig. 200). In such 

 cases the alveolar structure of the tumor is sometimes very evident to the 

 naked eye, and these tumors are therefore often called alveolar carcinoma. 

 Sometimes only a part of the tumor is affected in this way. 



Carcinoma Myxomatodes. The cellular elements of carciuomata may 

 suffer mucous softening, and thus larger and smaller cysts containing a 

 mucous fluid are sometimes formed. To this type of metamorphosed 

 tumor the above name is sometimes applied, but it more properly belongs 

 to carcinomata in which the stroma is composed of mucous tissue (Fig. 

 201). Such tumors are most fre- 

 quently found in the gastro-iutesti- 

 ual canal and nianima. 



Melano-Carcinoma. Tumors of 

 this class are rare, and are character- 

 ized by the presence of a variable 

 quantity of black or brown pigment 

 particles either in the stroma or in 

 the cells. They are usually soft and 

 malignant, and most frequently oc- 



J FIG. SOL-CARCINOMA MYXOMATODES. 



cur in the skin. 



From a tumor of the mamma. 

 MOLLUSCUM CONTAGIOSCM is the desig- 

 nation of small soft multiple growths of the skin, most frequent on the face, arms, and 



1 These tumors are often called "colloid cancers," but the material which character- 

 izes them is not true colloid. 



