Acute on chronic pancreatitis affecting the ectopic pancreas located in the jejunal mesentery: A case report.

Ectopic pancreas within the mesentery is rare. In this case report, a 61-year-old man with an ectopic pancreas within the jejunal mesentery for over 20 years developed chronic pancreatitis that progressed to acute exacerbation. Our computed tomography (CT) performed for acute abdomen assessment suggested acute appendicitis or Meckel's diverticulitis. However, a CT scan taken 20 years ago revealed a structure indicative of an ectopic pancreas in the mesentery, and further imaging findings taken 10 and 4 years ago confirmed progression to chronic pancreatitis. Furthermore, we found a pancreatic stone confined in the luminal structure that corresponded to the main pancreatic duct; this stone eventually caused acute exacerbation. In summary, we report a case of mesenteric ectopic pancreas that showed typical findings of progression and acute exacerbation of chronic pancreatitis on CT.