Intraductal papillary mucinous neoplasm originating from a jejunal heterotopic pancreas: report of a case.

We report a rare case of an intraductal papillary mucinous neoplasm (IPMN) originating from a jejunal heterotopic pancreas, found incidentally during surgery. A 75-year-old woman was referred to our department for surgical treatment of an abdominal aortic aneurysm (AAA) and a concurrent oropharyngeal tumor. During surgery to correct the AAA, we found a jejunal tumor incidentally and performed partial resection of the jejunum. Microscopically, the jejunal tumor showed dilated ducts containing intraluminal papillae lined with mucinous epithelium with low-grade cytological and architectural atypia within the pancreatic tissue. Immunohistochemical staining revealed MUC1 (-), MUC2 (-), MUC5AC (+), and MUC6 (-) proteins. To the best of our knowledge, only six cases of IPMN originating from a heterotopic pancreas have been reported in English, and this is the first report of an IPMN originating from a jejunal heterotopic pancreas.