1306 Endoscopic Mucosal Resection of Pancreatic Rest Presenting as a Submucosal Nodule in the Gastric Antrum

Abstract

INTRODUCTION: Pancreatic rest (PR) is defined as ectopic pancreatic tissue outside the normal pancreatic parenchyma, with a vascular and nerve supply separate from the pancreas itself and has a prevalence of 0.55-14%. It is believed to arise during rotation of the foregut, when fragments of the pancreas become separated from the main body and are deposited at ectopic sites. CASE DESCRIPTION/METHODS: An 82-year-old male with a history of GERD presented with episodes of epigastric abdominal pain of 2 month duration that did not improve despite PPI therapy. He denied any other symptoms such as bleeding, weight loss or change in bowel habits. Physical examination revealed a non-distended abdomen and mid-epigastric tenderness. An EGD performed for evaluation of GERD 3 years prior found an antral nodule. A repeat EGD was done this time for evaluation of the epigastric pain and showed a mobile submucosal nodule in the antrum measuring 7-8 mm, unchanged from before. EUS was performed for further evaluation and showed a hypoechoic gastric submucosal lesion, arising from the muscularis mucosa, 8 mm in size. No high-risk features were present. The area was resected using EMR and the defect was closed with clips. The EUS also showed a cystic dilation of the pancreatic duct in the pancreatic head measuring 5 mm, suspicious for main duct IPMN. Results from the EMR biopsy demonstrated heterotopic pancreatic tissue with focal low grade pancreatic intraepithelial neoplasia (PanIN), with clear margins and reactive gastropathy with focal intestinal metaplasia. There was resolution of the abdominal pain after the procedure. A repeat EGD/EUS will be done in 1 year. MRI will be performed in 6 months for surveillance of the pancreatic duct dilation. DISCUSSION: PR can be found virtually anywhere along the GI tract, but they are typically found in the stomach along the greater curvature and antrum. Although usually asymptomatic, the most reported symptom is mid abdominal pain. Complications of gastric ectopic pancreas include acute or chronic pancreatitis, necrosis, pseudocyst, gastric outlet obstruction and rarely carcinoma. PanIN is neoplastic epithelial proliferation that occurs in the small caliber pancreatic ducts; it is divided in 3 degrees based on architectural and nuclear atypia and has potential progression to invasive ductal adenocarcinoma. In our case, PanIN 1 was found on histology and the lesion was completely resected. PR should always be considered when evaluating a submucosal lesion of the GI tract.