Hepatobiliary and Pancreatic: Ectopic pancreas presented as a large paragastric mass.

Abstract

A 28-year-old African-American man with no previous medical history presented to the emergency department with epigastric pain and hematemesis. Physical examination revealed a soft abdomen without any tenderness, distension, or rigidity. Laboratory studies were significant for a hemoglobin of 12.9 g/dL, with normal liver enzymes and lipase. A computerized tomography (CT) scan of the abdomen with oral and intravenous contrast identified a soft tissue mass measuring 3 ×5 cm between the pylorus and gallbladder, seen in axial and coronal views (Fig. 1a & b). An upper endoscopy found erosive esophagitis but no gastric or duodenal lesions. Our differential diagnosis for the paragastric mass identified on CT imaging included gastrointestinal stromal tumor (GIST), lymphoma, leiomyoma, neuroendocrine tumor, ectopic pancreas, and chronic vascular malformation. Endoscopic ultrasound (EUS) was performed that visualized the mass situated between the stomach and gallbladder. Fine needle aspiration (FNA) of the mass demonstrated fragments of pancreatic acini (Fig. 1c), which established the diagnosis of ectopic pancreas. He was asymptomatic on 3-month follow-up and surveillance CT imaging revealed unchanged size. Ectopic pancreas is a rare anatomic entity where pancreatic tissue resides outside its typical location without anatomical or vascular connection to the true pancreas. Its pathogenesis and occurrence are implicated during embryogenesis and development of the normal pancreas. It is most commonly reported as a submucosal lesion in the gastric antrum or duodenum visualized on upper endoscopy. Contrast CT imaging may demonstrate ectopic pancreas, which enhances similarly to normal pancreatic tissue. It is difficult to identify because patients are usually asymptomatic. Some cases can have clinical manifestations depending on its size, location, and pathological changes with abdominal pain, hemorrhage, and gastrointestinal obstruction. Our case was atypical due to the lack of visualized submucosal lesion on upper endoscopy and location between the stomach and gallbladder. Contrast imaging with CT or magnetic resonance imaging (MRI), along with EUS for FNA for tissue sampling will help differentiate from other masses including malignant tumors. Surgical excision is used in symptomatic patients and is recommended if there is diagnostic uncertainty. Though a rare entity, gastroenterologists and radiologists should consider and recognize ectopic pancreas in the evaluation of extra-luminal upper gastrointestinal lesions.