THE DIGESTIVE SYSTEM. 



567 



to be more frequent in the small intestine and in the rectum than in the 

 large intestine. While various structural types are recorded, the so- 

 called lympho -sarcomata are most common. 1 



FIG. 344. ADENOMA OF THE RECTUM. 



Shows a portion of normal mucous membrane with extension of the adenomatous growth into the 

 submucosa. 



Adenomata are found in the duodenum, colon, and rectum. They 

 form flat infiltrations of the wall of the intestine (Fig. 344), or project 

 inward as polypoid tumors. They 

 are composed of tubular follicles, 

 like those of the intestinal mucous 

 membrane, and of a connective- 

 tissue stroma. In some of these 

 tumors the tubules have a regular 

 shape and arrangement; there is 

 no infiltration of surrounding tis- 

 sue ; the tumor is of benign nature. 

 In other tumors the tubules are ir- 

 regular in shape and arrangement, 

 and the growth infiltrates the sur- 

 rounding parts (Fig. 345). There 

 is no sharp dividing line between 

 these tumors and the carcinoniata. 



1 For resume and bibliography of sar- 

 coma of small intestine see Libman, Am. 

 Jour. Med. Sciences, vol. cxx., p. 309, 

 1900. For bibliography of sarcoma of 

 large intestine seeJopson and White, ibid., 

 vol. cxxii., p. 807. For a resume with bibli 

 see Wiener, Ziegler's Beitrage, Bd. xxv., p. 3 



FIG. 345. ADENOMA OF THE RECTUM. 



The growth has extended through the muscularis 



mucosae into the submucosa. 



?raphy of melano-sarcoma of the rectum 

 !, 1899. 



