ORIGINAL ARTICLE Clinicopathologic analysis of surgically proven intraductal papillary mucinous neoplasms of the pancreas in SNUH: a 15-year experience at a single academic institution Dae Wook Hwang & Jin-Young Jang & Seung Eun Lee & Chang-Sup Lim & Kuhn Uk Lee & Sun-Whe Kim # Springer-Verlag 2010 Abstract Purpose The clinical importance of intraductal papillary mucinous neoplasm of the pancreas (IPMN) has been increasing with a large number of newly diagnosed IPMN. This study was designed to explore the characteristics of resected IPMN and to determine the predictive factors for malignant and invasive IPMN. Methods Retrospective review of a prospectively collected database was performed on 187 consecutive patients following IPMN surgery between 1994 and 2008 at a tertiary institute. The main duct type IPMN was radiolog- ically defined as main pancreatic duct dilation >5 mm rather than previously defined ≥10 mm. Results The morphologic types of IPMN included 28 main duct (IPMN-M, 15.0%), 118 branch duct (IPMN-Br, 63.1%), and 41 mixed (IPMN-Mixed, 21.9%) IPMNs. There were 23 patients with adenoma, 106 borderline atypia, 15 carcinoma in situ, and 43 invasive carcinoma. Sixty-nine extrapancreatic malignancies were diagnosed in 61 (32.6%) patients. Based on multivariate analysis, IPMN- M was statistically significant predictor of malignancy/ invasiveness (p =0.013/p =0.028). In patients with IPMN- Br, the presence of mural nodule was a predictive factor for malignancy/invasiveness (p =0.005/p =0.002). In patients with IPMN-Mixed, mural nodule (p =0.038/p =0.047) and wall thickening (>2 mm, p =0.015/p =0.046) were risk factor for malignancy/invasiveness and elevated CA19-9 (p =0.046) for invasiveness. Conclusions The main pancreatic duct diameter (>5 mm) is a significant predictor for malignancy and invasiveness. There- fore, IPMN patients with main pancreatic duct dilatation (>5 mm) should be considered surgical resection. Mural nodule is the indicator of surgery in IPMN-Br and IPMN-Mixed. In case of IPMN-Mixed with wall thickening or elevated serum CA19-9, surgical resection is recommended. Keywords Malignant IPMN . Invasive IPMN . Predictive factor . Main pancreatic duct dilatation Mural nodule Introduction In 1982, Ohhashi first reported mucinous neoplasm of the pancreas (IPMN) as a distinct diagnostic entity; and which has transformed the management of pancreatic cystic lesions over the last 15 years. However, the natural history of IPMN is still not well understood [1]. Recently published papers and consensus meetings have demonstrated that IPMN is a premalignant lesion that progresses from adenoma to carcinoma. The longitudinal risk of malignancy is time dependent, and IPMNs arising from the main duct are known to be more aggressive than those from the branch duct [2–4]. The distinction between main and branch duct involve- ment has important implications in terms of cancer risk. However, the criteria for such distinction vary according to the methods used such as the size of main pancreatic duct, Dae Wook Hwang and Jin-Young Jang are contributed equally to this study. D. W. Hwang : J.-Y. Jang : S. E. Lee : C.-S. Lim : K. U. Lee : S.-W. Kim (*) Department of Surgery, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul 110-744, South Korea e-mail: sunkim@plaza.snu.ac.kr J.-Y. Jang : S.-W. Kim Cancer Research Institute, Seoul National University College of Medicine, Seoul, South Korea Langenbecks Arch Surg (2012) 397:93–102 DOI 10.1007/s00423-010-0674-6 Received: 8 March 2010 / Accepted: 15 June 2010 / Published online: 18 July 2010