Pathohistological subtype predicts survival in patients with intraductal papillary mucinous neoplasm (IPMN) of the pancreas.

OBJECTIVE: To investigate different subtypes of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas and their prognostic value.

BACKGROUND: IPMNs of the pancreas are estimated to have a better prognosis than pancreatic ductal adenocarcinomas (PDACs). In addition to the different growth types (ie, main duct vs. branch duct types), the histological subtypes of IPMNs (ie, intestinal, pancreatobiliary, gastric, and oncocytic type) are prognostically relevant. These subtypes can be characterized by different mucin (MUC) expression patterns. In this study, we analyzed the IPMNs from 2 pancreatic cancer referral centers by correlating the MUC expression, histological subtype, and clinical outcome.

METHODS: We re-evaluated all resections due to a pancreatic tumor over a period of 15 years. Cases with IPMNs were identified, and the subtypes were distinguished using histopathological analysis, including the immunohistochemical analysis of MUC (ie, MUC1, MUC2, and MUC5AC) expression. Furthermore, we determined clinical characteristics and patient outcome.

RESULTS: A total of 103 IPMNs were identified. On the basis of the MUC profile, histopathological subtypes were classified into the following categories: intestinal type [n = 45 (44%)], pancreatobiliary type [n = 41 (40%)], gastric type [n = 13 (12%)], and oncocytic type [n = 4 (4%)]. The following types of resections were performed: pancreatic head resections [n = 77 (75%)], tail resections [n = 16 (15%)], total pancreatectomies [n = 5 (5%)], and segment resections [n = 5 (5%)]. The 5-year survival of patients with intestinal IPMNs was significantly better than pancreatobiliary IPMNs (86.6% vs. 35.6%; P < 0.001). The pancreatobiliary subtype was strongly associated with malignancy [odds ratio (OR): 6.76], recurrence (P < 0.001), and long-term survival comparable with that of PDAC patients.

CONCLUSIONS: Evaluation of IPMN subtypes supports postoperative patient prognosis prediction. Therefore, subtype differentiation could lead to improvements in clinical management. Potentially identifying subgroups with the need for adjuvant therapy may be possible.