Positive surgical margins in surgically treated unifocal and multifocal IPMN

• The nature of surgical positive margins of resected IPMN is not fully clarified.
• Positive surgical margins are frequently found in multifocal IPMN.
• The recurrence of cysts is associated with positive margins only in unifocal IPMN.
• Most of positive margins found in multifocal IPMN could be false positive.

IntroductionAlthough treatment methods for the positive margins of surgically treated intraductal papillary mucinous neoplasms (IPMNs) are established, the significance of the positive surgical margins remains unclear. We aimed to clarify the risk factors of the positive margins and their impact on the recurrence of cystic lesions.MethodsFifty-five surgically treated IPMN cases occurring at the Ogaki Municipal Hospital from 2004 to 2013 were analyzed retrospectively.ResultsOut of the 55 IPMN patients who underwent pancreatectomy, positive surgical margins were found in 16 cases. Most of the positive surgical margin cases were found to be a multifocal IPMN; specifically, 9 out of 19 were a multifocal IPMN case, and 7 out of 36 were a unifocal IPMN case (47.4% and 19.4%, respectively, p = 0.030). Recurrences of cystic lesions in the remnant pancreases were found in 7 cases; 4 out of 16 cases were in the positive margin group, and 3 out of 39 were in the negative margin group (25.0% and 7.7%, respectively, p = 0.080). While a positive margin was a significant risk factor in unifocal IPMN (p = 0.031), it was not in multifocal IPMN (p = 0.90).ConclusionPositive surgical margins are frequently found in multifocal IPMNs and might include false positive margins.