Intraductal oncocytic papillary neoplasms of the pancreas and bile ducts: a description of five new cases and review based on a systematic survey of the literature

Abstract

Background Intraductal oncocytic papillary neoplasms (IOPN) are rare tumors of the pancreatic and biliary ductal system. It is not absolutely clear if the molecular and clinicopathologic characteristics of IOPN differ significantly from other related lesions, namely intraductal papillary mucinous neoplasms (IPMN). Therefore it is not clear if it is reasonable to consider IOPN as a separate diagnostic and clinical entity. Methods In order to describe the clinicopathologic characteristics of IOPN and to compare them with the IPMN profile, we performed a systematic review of the literature and additionally studied five previously unreported IOPN cases. Results IOPN differ from IPMN by lack of K-ras gene mutations in all studied cases. Several differences in the clinical and biological profile between IOPN and IPMN exist, but they are of quantitative rather than of qualitative nature. Additionally, pancreaticobiliary or gastric-foveolar IPMN components may coexist with IOPN component within a single lesion, which suggests at least a partial relation of the pathogenetic pathways of IPMN and IOPN. Importantly, the pathogenesis of accumulation of mitochondria and oxyphilic appearance of IOPN remains unknown. Conclusions At present, there are no reliable criteria other than histopathological picture and K-ras gene status to differentiate IOPN from IPMN. In particular, no clear differences in optimal treatment options and prognosis between these tumors are known. Further studies are needed to clarify the biology of IOPN and to establish their position in clinicopathologic classifications of pancreatic tumors.

Intraductal Oncocytic Papillary Neoplasms of the Pancreas

“…1 In a study of 283 IPMNs, Furukawa et al 6 reported a mean age of 60.3 years for 24 patients with IOPN, compared to 65.6, 64.5, and 69.2 years for gastric, intestinal, and pancreatobiliary types, respectively, and suggested an increased likelihood of earlier onset of IOPNs compared with that of the other histologic subtypes. However, other studies 9,10 have not reported a significant age difference. For example, a review by Liszka et al 10 of 24 pancreatic IOPN cases reported a mean age of 63.9 years with no significant age or sex differences between IOPN and IPMN overall.…”

“…However, other studies 9,10 have not reported a significant age difference. For example, a review by Liszka et al 10 of 24 pancreatic IOPN cases reported a mean age of 63.9 years with no significant age or sex differences between IOPN and IPMN overall.…”

“…10 The original report by Adsay 11 of IPMNs of all subtypes found 65% (range, 39%-89%) in the pancreatic head, 24% (range, 13%-31%) in the body, and 11% (range, 5%-21%) in the tail, making the distribution of IOPNs similar to that of IPMNs overall. The AFIP (Armed Forces Institute of Pathology) Atlas of Tumor Pathology notes that most IOPNs do not involve the main pancreatic duct.…”

“…In the abovementioned review by Liszka et al, 10 the most frequent presentation of IOPN was abdominal pain, seen in 13 of 24 patients (54%), followed by pancreatitis in 4 of 24 patients (17%). Their review also found 1 of 24 patients (4%) with weight loss and 1 of 24 patients (4%) with jaundice, and they noted a lower prevalence of these symptoms than that reported in the review by Belyaev et al 11 of 3725 patients with pancreatic IPMN of all subtypes, which found weight loss in 27% and jaundice in 16% of cases.…”

“…Approximately 20% of patients are asymptomatic, similar to IPMNs in general. 10 While diabetes mellitus has been associated with IPMNs including IOPN, there are currently no well-established risk factors for IPMN.…”