EUS of an atypical ectopic pancreas.

A 43-year-old woman presented with abdominal pain, nausea, and vomiting. She underwent computed tomography of the abdomen and pelvis that showed a gastric subepithelial mass. Esophagogastroduodenoscopy (EGD) revealed a smooth subepithelial mass in the fundus of the stomach, 5 cm distal to the gastroesophageal junction [Figure 1]. EUS demonstrated a homogeneous, hypoechoic 14 mm × 9.7 mm lesion, originating in the gastric submucosa [Figure 2]. The pancreas had an unremarkable endosonographic appearance. EUS-FNA was performed with a 22-gauge needle. While endosonographic appearance and location were most suspicious for gastrointestinal stromal tumors (GISTs), cytology was surprisingly consistent with an ectopic pancreas (EP).

Figure 1

Smooth mass in gastric fundus

Figure 2

EUS appearance of a hypoechoic, homogeneous mass in submucosa

Also known as pancreatic rest, an EP refers to pancreatic tissue in the gastrointestinal tract without any anatomical or vascular continuity with the normal pancreas. The most common site of EP is the stomach (25%–38%), followed by duodenum (17%–36%) and jejunum (15%–22%).[1] The most common gastric location in over 95% of the cases is the antrum, primarily near the greater curvature.[2] Similar lesions that may confound the diagnosis are GISTs, leiomyomas, lipomas, glomus tumors, and schwannomas among others.[3] Gastric EP has been described as an elevated subepithelial nodule overlaid by a normal mucosa, with central umbilication representing the orifice of a duct, a common feature in 35%–90% of EP cases.[456] Definitive diagnosis of EP is made on histopathology. Being a subepithelial lesion, conventional biopsies during EGD are only diagnostic in about 10% of cases.[4] Hence, EUS-FNA provides an excellent means of obtaining adequate tissue for definitive diagnosis. EP is usually found in the submucosa, but it may also involve the deep mucosa, muscularis propria, or serosa. It is typically hypoechoic with heterogeneous echotexture. An anechoic structure consistent with a duct may be seen.[256]

The location of the EP in the gastric fundus in our case was very atypical. The lesion lacked central umbilication and was more suspicious for GIST or leiomyoma based on endoscopic and EUS appearance and location, with EUS-FNA surprisingly showing a classic EP.

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Conflicts of interest

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