An 83-year old Japanese man was transferred to our hospital due to a 1-week history of melena and signs of disordered awareness. Esophagogastroduodenoscopy showed a villous tumor associated with massive white mucous discharge in the posterior wall of the gastric corpus, where pathologically identified mucin-producing epithelium with nuclear atypia had developed into a papillary form. An abdominal enhanced computed tomography scan demonstrated communication between the dilated main pancreatic duct and the gastric lumen. Based on these findings, we reached a diagnosis of gastric penetration by an intraductal papillary mucinous neoplasm (IPMN) of the main pancreatic duct. IPMN is partly characterized by expansive mucinous growth that may result in penetration into adjacent organs.
