Intraductal Papillary Mucinous Neoplasms of the Pancreas: Current Understanding and Future Directions for Stratification of Malignancy Risk

Abstract

The incidence of intraductal papillary mucinous neoplasms (IPMNs) has been increasing over the past decade, mainly owing to increased awareness and the increased use of cross-sectional imaging. The Sendai and Fukuoka consensus guidelines provide us with clinical management guidelines and algorithms; however, the clinical management of IPMNs continues to be challenging. Our incomplete understanding of the natural history of the disease, and the events and pathways that permit progression to adenocarcinoma, result in difficulties predicting which tumors are high risk and will progress to invasive disease. In this review, we summarize the current management guidelines and describe ongoing efforts to more clearly stratify IPMNs by risk of malignancy and identify IPMNs with malignant potential or ongoing malignant transformation.

FIGURE 1

Dysplastic changes seen in uniloculated and multiloculated IPMNs. Note the varying degrees of dysplasia in cysts that appear similar on imaging. Reproduced with permission from Hanania et al.

FIGURE 2

Algorithm for the management of suspected BD-IPMNs based on the 2012 Fukuoka Guidelines. Reproduced with permission from Tanaka et al. ^*Pancreatitis may be an indicationi for surgery for relief of symptoms. ^†Differential diagnosis includes mucin. Mucin can move with change in patient position, may be dislodged on cyst lavage, and does not have Doppler flow. Features of true tumor nodule include lack of mobility, presence of Doppler flow, and FNA of nodule showing tumor tissue. ^‡Presence of any one of thickened walls, intraductal mucin or mural nodules is suggestive of main duct involvement. In their absence main duct involvement in inconclusive. ^§Studies from Japan suggest that on follow-up of subjects with suspected BD-IPMN there is increased incidence of pancreatic ductal adenocarcinoma unrelated to malignant transformation of the BD-IPMN(s) being followed. However, it is unclear if imaging surveillance can detect early adenocarcinoma, and, if so, at what interval surveillance imaging should be performed.