Endocrine tumor and intraductal papillary mucinous neoplasm of the pancreas: A fortuitous association?

Objectives: Pancreatic endocrine tumors (PETs) and intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are rare diseases of the pancreas. Cases of association of endocrine and exocrine neoplasms of the pancreas have been reported, corresponding to mixed or amphicrine tumors. The aim of this report is to describe a series of 6 patients with an original association of IPMN and PET of the pancreas. Methods: Among 108 and 103 patients operated on in our center between January 1997 and December 2003 for PETs and IPMNs, respectively, we identified 6 patients with both PET and IPMN, diagnosed on pathologic examination with an immunohistochemical study. Results: Preoperative diagnosis was unspecified pancreatic tumor (n = 1), IPMN (n = 2), and association of PET and IPMN (n = 3). IPMN involved the main pancreatic duct in 4 patients and was classified as benign (n = 4), borderline (n = 1), or malignant noninvasive (n = 1). PETs measured 1.1 to 3 cm and were malignant in 1 patient (lymph node invasion). When analyzed by immunohistochemistry, 2 cases expressed glucagon, 1 expressed somatostatin, and 1 expressed insulin. Conclusion: This study describes a new aspect of endocrine-exocrine pancreatic neoplasm association. The frequency of the association of PET and IPMN is too large to be fortuitous. Further studies are needed to understand its mechanism.