154 PATHOLOGY 



organs or tissues. Rarely the tumor cells pass directly 

 into the circulation. This is more characteristic, how- 

 ever, of sarcoma. After attaining a certain size or stage 

 of development, degeneration of cancer occurs. This 

 may take the form of mucoid, colloid, hyalin, or amyloid 

 degeneration or necrosis, which is probably hastened 

 by infection. The degenerative changes, however, 

 never equal the growth of the tumor. 



Varieties of Cancer. Flat-celled Carcinoma. This 

 develops from all squamous or stratified epithelium. 



Melanocarcinoma. This is a flat-celled carcinoma 

 containing pigment. It develops from squamous or 

 stratified epithelium. 



Columnar-celled Carcinoma. This arises from tissue 

 containing cylindric epithelium. 



Colloid Carcinoma. This is a columnar-celled car- 

 cinoma in which the cancer cells have undergone colloid 

 degeneration, usually occurring in the digestive tract. 



Adenocarcinoma. This tumor develops from glandu- 

 lar tissue and simulates glandular tissue in its structure. 



This is divided into simple, in which the cells and 

 stroma are about equal; medullary, in which the cells 

 predominate; scirrhus, in which the stroma is in excess. 

 The scirrhous variety is found in the breast, stomach, 

 ovaries, and testicle. 



Giant-celled Carcinoma. A rare form in which the 

 cells attain a large size from various causes. 



