Histologic characteristics of pancreatic intraepithelial neoplasia associated with different pancreatic lesions.

Pancreatic intraepithelial neoplasia (PanIN) has been found in association with pancreatic ductal adenocarcinoma, intraductal papillary-mucinous neoplasm (IPMN), mucinous cystic neoplasm, and other pancreatic lesions, but the characteristics of PanINs associated with these lesions are not well characterized. In this study, 185 partial or total pancreatectomy specimens were collected, and 173 had complete slides for reviewed, which included 74 pancreatic ductal adenocarcinomas, 28 IPMNs, 7 mucinous cystic neoplasms, 44 other nonductal tumors, and 20 nontumorous lesions. Differences in grade, extent, and duct involvement among PanINs associated with different lesions were analyzed. Patients with PanINs were older than those without, regardless of associated tumor or lesions. No sex predilection was noted. PanINs were found in 89%, 96%, 86%, 64%, and 55% pancreata with ductal adenocarcinomas, IPMNs, mucinous cystic neoplasm, other nonductal tumors, and nontumorous lesions, respectively. PanIN 1 and 2 were commonly associated with all types of lesions, but high-grade PanIN 3 was more frequently associated with ductal adenocarcinomas. Ductal involvement of PanINs was more extensive in association with ductal adenocarcinomas than in any other types of pancreatic tumors or lesions. PanINs associated with pancreatic ductal adenocarcinomas affected both the main and branched ducts, whereas PanINs associated with other types of pancreatic tumors or lesions were mainly present in the branch ducts. No statistical differences were observed in distribution, extent, and grade of PanINs among IPMNs, mucinous cystic neoplasms, other nonductal tumors, and nontumorous lesions. Our study demonstrated a high concurrence between PanINs and other precancerous lesions and histologic features of PanINs associated with different pancreatic diseases.