TUMORS. 



377 



The adenomata of the breast deserve a rather close study. A 

 perfectly simple adenoma of this gland appears to be a very rare 

 growth. There is nearly always an association with diffuse fibroma, 

 forming an adenofibroma. These are often cystic, an accumulation 

 of a serous fluid in the acini causing their dilatation (cystic adeno- 

 fibroma) (Fig. 341). In other cases the fibromatous tissue grows 



FIG. 340. 



Adenoma of the pancreas. (Cesaris-Demel.) The atypical nature of the growth is revealed 

 by the character of the epithelial cells, their arrangement within the alveoli, and the 

 disposition of the latter with respect to each other and the interstitial tissue. 



into the acini, which are enlarged to receive these ingrowths from 

 their walls. The ingrowing masses of fibrous tissue are covered 

 with epithelium like that lining the rest of the acinus, a fact which 

 would be expected when we reflect that the ingrowth is a sort of 

 intrusion of the wall of the acinus itself. Sometimes these in- 

 growths have a papillomatous character, but more frequently they 

 have a globular form and give off globular branches within the 

 acinus. Sections of such growths often have a complicated appear- 

 ance. Irregular and branching bands of epithelium are seen cours- 

 ing through a mass of fibrous tissue. They are the epithelial 

 linings of the acini which have baen brought into contact by the 

 ingrowths of fibrous tissue, obliterating the lumina of the acini. 



