Disease Spectrum of Intraductal Papillary Mucinous Neoplasm With an Associated Invasive Carcinoma Invasive IPMN Versus Pancreatic Ductal Adenocarcinoma-Associated IPMN

Objectives: Current version of World Health Organization classification introduced the concept of "intraductal papillary mucinous neoplasm (IPMN) with an associated invasive carcinoma." The authors investigated the clinicopathologic characteristics and prognosis of this disease category according to tumor morphology and percentage of invasive component. Methods: Fifty-nine patients who underwent surgical resection of IPMN with an associated invasive carcinoma at Seoul National University Hospital were subgrouped according to the invasive component of less than 5% (minimally invasive [MI] intraductal papillary mucinous carcinoma [IPMC] [MI-IPMC]), 5%-50% (invasive IPMC and 50% or greater (pancreatic ductal adenocarcinoma [PDAC]associated IPMN [PDAC-IPMN]). Prognosis was compared with 219 curatively resected conventional PDAC. Results: Eleven MI-IPMCs (18.6%), 24 IPMC-Is (40.7%), and 24 PDAC-IPMNs (40.7%) were identified. With the transition from MIIPMC to IPMC-I and PDAC-IPMN, percentage of advanced T (P < 0.001) or N stage (P = 0.001), expression of 5100A4 (P = 0.004), p53 (P = 0.028), and CD24 (P = 0.009) increased; and SMAD4 expression decreased (P < 0.001). The overall 5-year survival rates for MIIPMC, IPMC-I, and PDAC-IPMN were 80.8%, 59.0%, and 29.3%, respectively (P < 0.001). Pancreatic ductal adenocarcinoma-associated IPMN had poor prognosis compared with MI-IPMC (P = 0.011) or IPMC-I (P = 0.026) but had comparable prognosis with conventional P DAC (P = 0.138). Conclusions: Pancreatic ductal adenocarcinoma-associated IPMN has different clinicopathological characteristics compared with the IPMC-I. Intraductal papillary mucinous neoplasm with an associated invasive carcinoma is composed of a wide spectrum of disease.