Gastric Outlet Obstruction Due to Secreting Heterotopic Pancreas

Abstract

Purpose: Introduction: Heterotopic pancreas (also termed as pancreatic rests) is a rare congenital anomaly of the gastrointestinal tract. Presence of heterotopic pancreatic tissue within the stomach is a rare cause of gastric outlet obstruction. We report an interesting case of gastric outlet obstruction as a complication of heterotopic pancreas presenting as a submucosal cyst in the gastric antrum diagnosed with endoscopic ultrasound (EUS). Case report: A 22 year old female with history of gastroesophageal reflux disease presented with 6 week history of progressively worsening nausea, emesis, heartburn and early satiety with weight loss. Esophagogastroduodenoscopy to the descending duodenum revealed a large, submucosal antral gastric lesion with partial gastric outlet obstruction. Abdominal computer tomography showed a 4 cm×2.7 cm low-density mass in the distal stomach. Subsequent EUS demonstrated a large 5 cm submucosal cystic lesion in the gastric antrum in layer three. EUS guided fine needle aspiration of the cyst revealed amorphous material. Biochemical studies of the fluid showed elevated amylase level with a value of 4,878 U/L and a CEA level of 96.6 ng/ml. Due to persistent symptoms, patient subsequently underwent distal gastrectomy with Roux-En-Y anastomosis. Final histological diagnosis showed gastric heterotopic pancreas. Discussion: Heterotopic pancreas is defined as the presence of pancreatic tissue outside normal pancreas that lacks anatomic or vascular continuity with main pancreas itself. Most common sites for heterotopic pancreas are stomach (25-38%), duodenum and jejunum. Complications include mechanical obstruction like gastric outlet obstruction in our patient, cyst formation, acute or chronic pancreatitis, bleeding due to ulceration and malignant transformation. Differential diagnosis of gastric submucosal lesions includes gastrointestinal stromal tumors, duplication cyst, lymphoma and gastric carcinoma. On endoscopy, heterotopic pancreas appears as a broad based submucosal lesion that may have umblication on the mucosal surface indicating the site of draining duct. EUS has proven to be very useful in diagnostic evaluation. Fine needle aspiration via EUS allows cytological evaluation of submucosal lesions which can usually confirm the diagnosis. Definite diagnosis of pancreatic heterotopia is by histology of the lesion. Symptomatic lesions are treated surgically. Submucosal lesions of gastrointestinal tract present a diagnostic challenge for gastroenterologists. Heterotopic pancreas, albeit a rare entity, should be considered in cystic lesions of gastric wall causing gastric outlet obstruction.