Endoscopic ultrasonography findings of pancreatic parenchyma for predicting subtypes of intraductal papillary mucinous neoplasms

Background and Aims:
The subtypes of intraductal papillary mucinous neoplasms (IPMNs) are closely associated with the clinicopathological behavior and recurrence after surgical resection. However, there are no established non-invasive methods to confirm the subtypes of IPMNs without surgery. The aim of this study is to predict the subtypes of IPMNs using the findings of endoscopic ultrasonography (EUS).

Methods:
Sixty-two consecutive patients with IPMNs who underwent EUS before surgery were retrospectively reviewed. The following EUS findings were analyzed and their relationship with the subtypes was evaluated: diameter of the main pancreatic duct, cyst size, number of cysts, height of mural nodule, early chronic pancreatitis (CP) finding, fatty parenchyma and atrophic parenchyma.

Results:
The subtypes of IPMNs were as follows: gastric (G)-type 38 (61%), intestinal (I) -type 14 (23%) and pancreatobiliary (PB) -type 10 (16%). Fatty parenchyma was significantly associated with G-type (P < 0.0001). Early CP findings ≥ 2 and atrophic parenchyma were significantly correlated with I-type (P < 0.0001). PB-type was significantly associated with pancreatic parenchyma without early CP findings or fatty degeneration in comparison to the other subtypes (P < 0.0001). Using the above characteristic EUS findings, the sensitivity, specificity, and accuracy were as follows: 63%, 92% and 74%, respectively, in G-type, 57%, 96% and 87% in I-type, and 90%, 94% and 94% in PB-type.

Conclusions:
The evaluation of EUS findings, especially focused on the pancreatic parenchyma, has the potential to predict the subtypes of IPMN.

© 2021 IAP and EPC. Published by Elsevier B.V. This manuscript version is made available under the CC-BY-NC-ND 4.0 License. http://creativecommons.org/licenses/by-nc-nd/4.0/. This is the accepted manuscript version. The formal published version is available at [https://doi.org/10.1016/j.pan.2021.01.026] .