Incidentally Discovered Pancreatic Intraepithelial Neoplasia: What Is Its Clinical Significance?

Abstract

Pancreatic intraepithelial neoplasia (PanIN) is a presumed precursor of pancreatic ductal adenocarcinoma (PDAC). We assessed the relationship between incidental PanIN after resection of non-adenocarcinoma lesions and the development of metachronous PDAC in the remnant. We retrospectively reviewed the clinicopathologic data of patients who underwent pancreatectomy for non-PDAC from January 2000 to January 2010. Intraductal papillary mucinous lesions were excluded. All available postoperative imaging and clinical follow-up data were reviewed; the risk of developing PDAC was assessed in patients with a minimum follow-up time of 6months and with imaging studies available for review. A total of 584 patients were analyzed. Median age was 59years (range 10-85years), and 338 (58%) were female. The most common lesions for which resection was performed were serous cystic neoplasms (17%), pancreatic neuroendocrine tumors (38%), metastatic tumors (9%), and mucinous cystic neoplasms (7%). PanIN was identified in 153 (26%) patients. The majority of these patients had PanIN-1 or -2 (50 and 41%, respectively), whereas 13 (8%) had PanIN-3. Of the 506 (87%) patients with adequate follow-up (median 3.7years, range 0.5-12.6years), 1 patient (0.2%) with PanIN identified at the time of initial resection developed cancer in the remnant. This occurred 4.4years after a distal pancreatectomy in the setting of PanIN-1B. No patient with PanIN-3 developed cancer during follow-up. PanIN was identified in 26% of patients who underwent resection for histopathology other than PDAC. The presence of PanIN of any grade did not result in an appreciable cancer risk in the pancreatic remnant after short-term follow-up.