Intraductal Papillary Mucinous Neoplasm Complicated by a Fistulous Communication Between Common Bile Duct and Pancreatic Duct

Abstract

Purpose: Introduction: Intraductal papillary mucinous neoplasms (IPMN) are increasingly recognized pancreatic neoplasms. Case Description: A 66 yo white male with a history of alcohol abuse and recurrent pancreatitis initially presented with acute pancreatitis. Lipase was markedly elevated but liver function tests (LFT) were within normal range. A CT scan of the abdomen showed a dilated pancreatic duct (PD). The patient was lost to follow up. He presented two years later with pancreatitis, abnormal LFT's, and new common bile duct (CBD) dilation on CT. Laboratory values were significant for alkaline phosphatase 1150, aspartate aminotransferase 212, alanine aminotransferase 320, total bilirubin 7.1, direct bilirubin 5.7, INR 1.6, WBC 29 with 89% segmented neutrophils, and lipase 459. He had an endoscopic ultrasound (EUS) performed which suggested chronic pancreatitis, persistent dilation of the PD at 8 mm, CBD 10 mm, and suggestion of a fistulous communication between the PD and CBD. He underwent endoscopic retrograde cholangiopancreato-graphy (ERCP) which revealed the classic “fish mouth” ampulla. During cannulation of the CBD, the wire was seen exiting the PD consistent with the fistulous communication demonstrated on EUS. Cholangiocospy during ERCP clearly demonstrated papillary projections in the proximal CBD confirming the diagnosis of IPMN. Patient underwent a successful Whipple procedure. Surgical pathology reported IPMN with high grade dysplasia involving the main PD with foci of invasive carcinoma. Discussion: IPMNs are pancreatic neoplasms that grow within the ductal system. They are characterized by production of thick mucinous fluid tumor cells. They are typically located in the head of the pancreas and can cause dilation of the pancreatic ducts. They are classified as adenoma, borderline, or carcinoma and some IPMNs can progress to invasive carcinoma if left untreated. A rare complication of IPMNs is fistula formation. Fistulas have most commonly been recognized in association with IPMNs post-operatively. Fistulas have also been documented when an IPMN is present between the pancreas and stomach as well as the pancreas and biliary tree. While our patient's PD dilation may have initially been explained by chronic pancreatitis it is important for clinicians to consider IPMN in this setting, especially in conjunction with CBD dilation and abnormal LFT's.