Intraductal papillary mucinous neoplasms (IPMN) of the pancreas include a spectrum of dysplasia ranging from minimal mucinous hyperplasia to invasive carcinoma and are extensive tumors that often spread along the ductal tree. Several studies have demonstrated that preoperative imaging is not accurate enough to adapt the extent of pancreatectomy and have suggested routinely using frozen sectioning (FS) to evaluate the completeness of resection and also to check if ductal dilatation is active or passive, in order to avoid an excessive pancreatic resection. Separate main duct and branch duct analysis is needed due to the difference in the natural history of the disease. FS accuracy averages 95%. Eroded epithelium on the main duct, severe ductal inflammation mimicking dysplasia and reactive epithelial changes secondary to obstruction can lead to inappropriate FS results. FS results change the planned extent of resection in up to 30% of cases. The optimal cut-off leading to extend pancreatectomy is not consensual and our standard option is to extend pancreatectomy if FS reveals: (1) at least IPMN adenoma on the main duct; or (2) at least borderline IPMN on branch ducts; or (3) invasive carcinoma. However, the decision to extend resection must be taken after a multidisciplinary discussion since it does not exclusively depend on the FS result but also on age, general condition and expected prognosis after resection. The main limitation of using FS is the existence of discontinuous ("skip") lesions which account for approximately 10% of IPMN in surgical series and can lead to reoperation in up to 8% of cases.
Keywords: Branch duct; Dysplasia; Frozen section; Intraductal papillary and mucinous tumor; Main duct; Pancreas.