A Case of Adenocarcinoma of an Ectopic Pancreas in the Stomach

Abstract

Adenocarcinoma arising from an ectopic pancreas of the stomach is rare. The case of a 77-year-old woman with adenocarcinoma arising from an ectopic pancreas of the stomach after endoscopic submucosal dissection (ESD) for early-stage gastric cancer is reported. Seven years after ESD, her tumor marker (CA19-9) level was elevated. Contrast-enhanced computed tomography (CT) showed a 25-mm mass near the pylorus. Positron emission tomography-CT showed abnormal uptake of 18F-fluorodeoxyglucose. Endoscopic ultrasonography (EUS) showed the mass located out of the stomach, and EUS-guided fine-needle aspiration was performed. Histological examination demonstrated adenocarcinoma, but the degree of differentiation was different from that of the previous gastric cancer. Distal gastrectomy with D2 lymph node dissection was performed, suspecting a lymph node recurrence of the previous gastric cancer. Pathological examination showed a moderately differentiated adenocarcinoma surrounded by ectopic pancreas of Heimlich type I, located in the submucosal and subserosal layers near the pyloric ring. The lesion was not exposed to the mucosal surface. Pancreatic ductal tissue was found at the border of the tumor, and carcinoma in situ was found inside the duct. Based on these findings, the tumor was diagnosed as adenocarcinoma arising from an ectopic pancreas of the stomach.