MRI-Based Pancreatic Atrophy Is Associated With Malignancy or Invasive Carcinoma in Intraductal Papillary Mucinous Neoplasm

Abstract

Background: Abrupt change in the caliber of the main pancreatic duct (MPD) with distal pancreatic atrophy (PA) was considered as one of worrisome features in the International Association of Pancreatology guideline and American College of Gastroenterology guideline for the management of intraductal papillary mucinous neoplasms (IPMNs). However, this feature was not included in other guidelines. Moreover, the association between PA alone and malignancy in IPMNs has not been fully evaluated. In the present study, we investigated the role of image-based PA in identifying malignant IPMNs or invasive carcinoma.

Methods: A total of 186 patients with IPMNs were included for analysis. The tumor size, location, MPD diameter, presence of a mural nodule (MN), and PA were evaluated using magnetic resonance imaging. Demographic information and serum carbohydrate antigen 19-9 and carcinoembryonic antigen (CEA) levels were also collected. IPMNs with high-grade dysplasia and associated invasive carcinoma were regarded as malignant IPMNs.

Results: PA was observed in 34 cases (18.3%). The occurrence of malignant IPMNs or invasive carcinoma in patients with PA were significantly higher than in those without PA (52.9% vs. 22.3%; 44.1% vs. 8.9%, all P < 0.01). Multivariate logistic regression analysis showed that PA was an independently associated factor for malignant IPMNs [odds ratio (OR) = 2.69, 95% confidence interval (CI): 1.07-6.78] or invasive carcinoma (OR = 7.78, 95%CI: 2.62-23.10) after modified with confounders. Subgroup analysis in MPD-involved IPMNs also indicated that PA was an independently associated factor for invasive carcinoma (OR = 9.72, 95%CI: 2.43-38.88). PA had a similar performance with MPD plus MN [the area under the curve (AUC) was both 0.71] in identifying malignancy. PA had a higher performance in identifying invasive carcinoma in MPD-involved IPMNs than MN (AUC = 0.71 vs. 0.65, P = 0.02).

Conclusion: Our data showed that imaging-based PA was associated with malignancy or invasive carcinoma regardless of abrupt change in the caliber of MPD in IPMNs. PA had an acceptable performance in identifying malignant IPMNs.

Keywords: intraductal papillary mucinous neoplasms; invasive carcinoma; malignancy; pancreas; pancreatic atrophy.

Figure 1

The prevalence of pancreatic atrophy in all intraductal papillary mucinous neoplasms (IPMNs), MD-involved IPMN, and BD-IPMNs. The p-values for trends were less than 0.01 and was 0.21. “Low” means low and intermediate grade.

Figure 2

Three cases of IPMNs with (A, B) or without (C) pancreatic atrophy. A: A 67-year-old woman with IPMN-derived invasive carcinoma in pancreatic head (white arrow). Atrophy occurred in the pancreatic body and tail. Pancreatic duct dilatation occurred (below). B: A 61-year old man with low-grade IPMN in the pancreatic head. Pancreatic duct dilatation occurred (white arrow), but pancreatic atrophy was not observed. C: A 57-year old woman with low–moderate grade of IPMN in pancreatic head. An abrupt change in the caliber of the main pancreatic duct (bottom white arrow) with body pancreatic atrophy was observed (the ratio between the main pancreatic duct diameter and the width of the total gland was 0.54, white arrow).

Figure 3

Receiver operating characteristic (ROC) curves for identifying invasive carcinoma in all IPMNs (A) [area under the curve (AUC) = 0.78 vs. 0.71, 0.71] and MD-involved IPMNs (B) (AUC = 0.76 vs. 0.65, 0.71). MPD, main pancreatic duct; MN, mural nodule; PA, pancreatic atrophy.