288 THE MICROSCOPIST. 



(page 239) belong to the adenomata. They proceed from 

 the rounded or elongated saccular epithelial masses which 

 form the processes of the Graafian follicles. 



Adenomata are usually benign formations, but have a 

 tendency to pass into cancer. 



3. Carcinoma, or Cancer. The term cancer is applied 

 to an epithelial new formation which may occur as a 

 tumor or infiltration in any tissue or organ, which is quite 



Adenoma mammae. Genuine epithelial carcinoma (Billroth). 1-300. After EINDFLEISCH. 



malignant, but which is generally (not always) chronic in 

 its course. Its cells are not peculiar, being similar to 

 other physiological cells, but by their rapid multiplication 

 and metamorphoses are followed by destruction of the 

 affected parts of the organ, and finally of the organ itself. 

 It usually returns after extirpation, or it may secondarily 

 affect internal organs. We have seen, page 264, that ma- 

 lignancy is by no means an exclusive property of cancers, 

 since other new formations may be equally malignant. 



Cancer occurs in various forms, as scirrhus, encephaloid, 

 and colloid. Some consider epithelioma also to be a form 

 of cancer, but as it is not as malignant as other forms, 

 and is characterized by its local growth, it may be best 

 considered separately as cancroid rather than true cancer. 



