THE DIGESTIVE SYSTEM. 



573 



tumors in the omentum, mesentery, intestinal wall, liver, lungs, and in 

 other viscera. ' 



Endotheliomata similar in structure to those originating in the pleura 

 are of occasional occurrence in the peritoneum. They may form single 

 well-defined tumors or flattened masses in the thickened peritoneum. 

 Cuboidal or polyhedral cell masses often grouped along the side of auas- 



FIG. 348. PAPILLARY FIBROMA- PAPILLOMA- OF PERITONEUM. 



This growth was secondary to a similar tumor originating in the ovary and connected with that or- 

 gan (see Fig. 446). Detached portions of the original tumor were transplanted to various regions of the 

 peritoneum. 



toniosing channels in the new-formed or old connective-tissue stroma 

 sometimes lend a glandular appearance to the type of growth. 



These tumors apparently originate in the true eudotheliuni of the 

 subperitoneal lymph channels and not in the flat cells often called endo- 

 thelial mesothelium lining the peritoneum. 



Carcinoma of the peritoneum is usually secondary to this disease in 

 adjacent regions, stomach, liver, uterus, etc. Its structural characters 

 correspond with those of the primary growth. It is apt to appear in 

 the form of numerous larger and smaller whitish nodules, sometimes 

 local, sometimes widely disseminated over the peritoneal surfaces. Such 

 tumors, when small and numerous, may readily be mistaken for tubercles. 



1 See for bibliography Steele, Am. Jour. Med. Science, vol. cxix., p. 311. 



