Duodenum diverticulum

Due to the above mentioned rotations of the stomach, the presumptive duodenum will bend into a C shape and will be displaced to the right until it lies against the dorsal body wall and becomes secondarily retroperitoneal. A system of digestive glands develops from endodermal buds of the duodenum, including the liver parenchyma, the gall bladder and their ducts (derived from the hepatic diverticulum), as well as the pancreatic parenchyma and its ducts (derived from the fusion of the dorsal and ventral pancreatic ducts) (Fig. 3.1). 

Ectopic pancreas is described as the presence of pancreatic tissue without an anatomic or vascular connection with the pancreatic body. This ectopic tissue maybe localized anywhere in or outside of the gastrointestinal tract. Common sites in the gastrointestinal tract are the stomach, duodenum, and the proximal jejunum, and less commonly in the appendix, the diverticulum of Meckel in 5% of cases, or the ileum in just 1% of cases. Extraintestinal localization, such as in the wall of the gallbladder, the bile ducts in the liver, the hilum of the spleen, the omentum, the perigastric or periduodenal area, may be seen in only 4% of cases (Gazelle et al. 1998). 

Enteroliths are concretions of precipitated bile acids which form in the intestinal tract and thus differ from gallstones, which consist mainly of cholesterol, bilirubin, or both. All but two enteroliths of which the composition has been determined have been found to be composed of choleic acid, a molecular coordinate complex of deoxycholic acid, and usually a fatty acid in a proportion of about 8 1. Of the remaining two, one enterolith was found in an afferent gastroenterostomy loop (84) and the other in a diverticulum of the second portion of the duodenum (85). Both of these enteroliths consisted of a mixture of unconjugated primary bile acids, cholic and chenodeoxycho-lic acids. 

Fig. 2.38a,b. Duodenum Diverticulum. Double Contrast barium study (a) and endoscopy (b) clearly show the diverticulum. Note the common peri-ampullary location... 

Duodenal diverticulum is a frequent incidental finding, found in up to 10% of upper GIT barium studies. The most common site is at the mesenteric border of the descending and horizontal parts of the duodenum, particularly near the ampulla of Vater. Indeed the ampulla may be situated within a diverticulum so that the common bile duct drains into such a periampullary diverticulum. On CT, the diverticulum is seen as an air-filled pocket, or it may demonstrate an air-fluid level with contrast medium and food debris in the dependent part (Fig. 9.3) (Stone et al. 1989 Jayaraman et al. 2001 ZissiN et al. 2002). 

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