Revised points of the international consensus guidelines 2012 for the management of IPMN

Abstract

The 2012 consensus guidelines lowered the threshold of the main duct caliber to 6mm without jeopardizing specificity while increasing sensitivity of diagnosis of main duct(MD-) IPMN. To stratify the malignant risk of branch duct(BD-) IPMNs more effectively "high-risk stigmata" and "worrisome features" have been defined. Indication for resection of BD-IPMN has become more conservative, excluding the size criterion. Since Japanese investigators recommend twice-a-year imaging studies of all BD-IPMNs to detect concomitant pancreatic carcinoma, lengthening of the surveillance interval after two years of no change remains controversial. IPMNs with strong suspicion of invasive or noninvasive carcinoma are an indication for standard pancreatectomy with lymph node dissection, while nonanatomical, limited pancreatectomy may be considered in those without malignant stigmata. Histological types of invasive IPMNs (colloid or tubular) and subtypes of IPMNs (gastric, intestinal, pancreatobiliary, or oncocytic) predict prognosis of the patients. Frozen section histology of the pancreatic margin is mandatory during resection of IPMN and high-grade dysplasia or invasive carcinoma requires additional resection. After resection, even patients with low-grade dysplasia need twice-a-year surveillance in view of the relatively high incidence of concomitant carcinoma, while those with invasive IPMN and high-grade dysplasia need surveillance with shorter intervals.