Objectives: Prognostic value of histological subtypes of pancreatic intraductal papillary mucinous neoplasm (IPMN) has been reported to have conflicting results. The authors investigated the clinicopathological characteristics and prognostic significance of the histological subtypes of IPMNs with various degrees of dysplasia.
Methods: Two hundred thirteen patients with surgically treated pancreatic IPMN at a single tertiary care referral center were included. Pathological slides were thoroughly reviewed by a specialized pathologist.
Results: Of the 213 patients, 38 low-grade, 97 intermediate-grade, and 18 high-grade dysplasia and 59 IPMNs with an associated invasive carcinoma (invasive IPMN) were identified. Histological subtypes consisted of 135 gastric (63.4%), 38 intestinal (17.8%), 38 pancreatobiliary (17.8%), and 2 oncocytic types (0.9%). Histological subtypes were associated with radiological type (P < 0.001), degree of dysplasia (P < 0.001), and T stage (P < 0.001). The proportions of invasive IPMN were 14.1%, 42.1%, 57.9%, and 100% of gastric, intestinal, pancreatobiliary, and oncocytic types, respectively. Disease-specific survival was not affected by histological subtype in overall patients (P = 0.881). For invasive IPMNs, histological subtypes had a marginal significance on survival (P = 0.050), which lost statistical significance after multivariate analysis (P = 0.341).
Conclusions: Although histological subtypes are associated with the degree of dysplasia, histological subtypes have limited prognostic value for pancreatic IPMNs.