DUODENAL CAECINOMA. 365 



considerable area. The bearing of the peritoneal and colic 

 relations 011 the possibility of perforation into the greater sac 

 and into the transverse colon is obvious. 



As the result of duodenal ulceration cicatricial stenosis may 

 occur, or the presence of dense external adhesions may cause 

 considerable obstruction. 



Pressure on the duodenum sometimes leads to obstruction. 

 The pressure may be due to a movable right kidney, and is then 

 intermittent. A stomach much distended with fluid may exercise 

 pressure on the terminal portion of the duodenum which lies 

 behind it. Collapse of the small intestine may cause the superior 

 mesenteric vessels to become tightly drawn across the transverse 

 portion of the duodenum, and may thus obstruct it. 



Malignant disease of the duodenum is very uncommon. A 

 carcinoma of the first part appears as a movable tumour, with 

 symptoms very like those of pyloric cancer. If the obstruction 

 is considerable no regurgitation of bile is possible. Carcinoma 

 is more likely, however, to arise in the neighbourhood of the 

 papilla of Vater. The tumour is then fixed, even in its early 

 stages, for this part of the duodenum is not movable, being 

 retroperitoneal. Obstruction of the biliary and pancreatic ducts 

 will complicate the intestinal obstruction which results. Eetro- 

 peritoneal growths arising in the lymphatic glands sometimes 

 encircle and infiltrate the retroperitoneal portion of the duodenum, 

 and may compress the bile duct and pancreatic duct at the same 

 time. 



Malformations of the duodenum are rare. When the duodenum 

 is prolapsed, traction by the bile duct may draw out a small 

 diverticulum. Diverticula may also arise from ulceration and 

 yielding of the wall. A diverticulum sometimes projects above 

 the biliary papilla and passes towards the head of the pancreas ; 

 this has been attributed to the influence of one of the outgrowths 

 from which the pancreas is developed. External adhesions at 

 the base of an ulcer may also drag out the duodenal wall in the 

 form of a pouch. 



Rupture of the duodenum usually results from the passage 



