Differentiation of Malignant and Benign Intraductal Papillary Mucinous Neoplasm by Repeated Pancreatic Juice Cytology Combined with Carcinoembryonic Antigen Level in Pancreatic Juice

Objective The sensitivity of pancreatic juice cytology for intraductal papillary mucinous neoplasm is insufficient. We evaluated the usefulness of repeated pancreatic juice cytology via an endoscopic naso-pancreatic drainage tube combined with carcinoembryonic antigen level of pancreatic juice for the diagnosis of malignant intraductal papillary mucinous neoplasm. Methods Between April 2004 and February 2015, conventional pancreatic juice cytology and repeated pancreatic juice cytology were performed in 30 and 45 patients with intraductal papillary mucinous neoplasm, respectively. The carcinoembryonic antigen cutoff level of pancreatic juice for differentiation of malignant intraductal papillary mucinous neoplasm was determined from examination of 46 patients. The relationship between carcinoembryonic antigen level in pancreatic juice and carcinoembryonic antigen immunohistochemical expression of 32 resected tissues was also evaluated. Results The sensitivity, specificity, and accuracy of repeated pancreatic juice cytology were 52%, 83%, and 60%, respectively; the sensitivity was significantly higher than that of the conventional method (p=0.01). When repeated pancreatic juice cytology values and carcinoembryonic antigen level in pancreatic juice >72 ng/mL were combined, the sensitivity, specificity, and accuracy were 67%, 88%, and 72%, respectively and were 83%, 75%, and 80%, respectively, in patients with “worrisome features” and main pancreatic duct diameters from 5 to 9 mm. Post-ERCP pancreatitis was detected frequently by repeated pancreatic juice cytology in branch duct type intraductal papillary mucinous neoplasm. The carcinoembryonic antigen level of pancreatic juice in immunohistochemical analysis was correlated with carcinoembryonic antigen expression in resected specimens. Conclusions The repeated pancreatic juice cytology method was feasible for intraductal papillary mucinous neoplasm patients with main pancreatic duct diameters ≥5 mm. This method combined with the carcinoembryonic antigen level of pancreatic juice may be useful for patients with “worrisome features” and main pancreatic duct diameters of 5–9 mm. Received April 04th, 2017-Accepted April 29th, 2017