Ectopic pancreas

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). 

Better delineation ofectopic pancreas maybe seen on CT as a round mass with a variation of borders in the antral wall of the stomach a localization in the fundus is very unusual. After contrast injection the ectopic pancreatic tissue will enhance with a similar pattern to the normal pancreas. Cystic dilation of an ectopic pancreatic duct, ectopic pancreatic tissue in the perigastric fat, or malignant transformation of ectopic pancreas have been described but are rarely seen (Cho et al. 2000). 

An ectopic pancreas is characterized as a hypoechoic tumor located mainly in the submucosal layer with thickening of the adjacent proper muscle layer (Fig. 19.6). A tiny cystic area representing the ductal structure may be demonstrated. 

Fig. 2.22a,b. Ectopic Pancreas in the stomach. Double Contrast barium study (a) shows a small nodule in the antrum of the stomach (bottom left of image). Endoscopy (b) demonstrates the characteristic round umhilicated lesion situated a few centimeters proximal to the pylorus. Biopsy confirmed ectopic pancreas (pancreatic rest)... 

Ectopic ACTH syndrome refers to excessive ACTH production resulting from an endocrine or nonendocrine tumor, usually of the pancreas, thyroid, or lung (e.g., small-cell lung cancer). 

Figure 6.2 Ectopic lipid accumulation and insulin resistance. As obesity progresses, lipid accumulation occurs in other organs ( ectopic sites). The lipid accumulation in these ectopic sites leads to insulin resistance (impaired glucose uptake in muscle, and increased glucose output in liver), and to impaired insulin seoretion from the p-cells of the pancreas.

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