Formation of Pancreatoduodenal Fistula in Intraductal Papillary Mucinous Neoplasm of the Pancreas Decreased the Frequency of Recurrent Pancreatitis.

Intraductal papillary mucinous neoplasms (IPMN) of the pancreas are characterized by proliferation of mucin-secreting cells in the main pancreatic duct (PD) or its branches. The secreted thick mucin usually leads to PD obstruction and dilation. A common complication of IPMN is recurrent acute pancreatitis secondary to poor pancreatic fluid drainage, and rarely, pancreatobiliary and pancreatointestinal fistulae. We describe a unique case of IPMN in a 57-year-old male who was referred to our institution for evaluation of recurrent acute pancreatitis. After extensive evaluation, he was diagnosed with main duct IPMN. Intraductal PD biopsy revealed intestinal type IPMN with intermediate grade dysplasia. Patient was managed clinically by large caliber (10 French) PD stenting which eliminated his recurrent acute pancreatitis. The patient was initially referred for pancreatic resection; however, surgery was aborted and evaluated to be high risk with high morbidity secondary to the extensive adhesions between the pancreas and surrounding structures. Patient remained clinically stable for a few years except for an episode of acute pancreatitis that happened after a trial of stent removal. Subsequently, the patient did well after the PD stent was replaced. Recently, repeat abdominal imaging revealed a large pancreatoduodenal fistula which was confirmed on repeat endoscopic retrograde cholangiopancreatography. We were able to perform pancreatoscopy by advancing a regular upper scope through the fistula and into the PD. Interestingly, the fistula relieved the symptoms of obstruction and subsequently decreased the frequency of recurrent pancreatitis episodes with no further episodes at 6 months follow-up. This case highlights the importance of providing adequate PD drainage to reduce the frequency of recurrent acute pancreatitis in the setting of main duct IPMN, especially if the patient is not a surgical candidate. Also, physicians need to monitor for complications such as fistula formation between the pancreas and surrounding structures in the setting of chronic inflammation due to recurrent episodes of pancreatitis. Early identification of a fistula is important for surgical planning. Furthermore, since recent studies suggested a higher incidence of additional primary malignancies in patients with IPMN of the pancreas compared to the general population, patients may be considered for screening for other primary malignancies.