Pancreatic suppurative process: a rare case of pancreato-duodenal fistula with an intraductal papillary mucinous neoplasm

Introduction

Intraductal papillary mucinous neoplasms (IPMNs) of pancreas are lesions originating in the main or accessory pancreatic ducts due to intraductal proliferation of mucin-secreting papillary cells (1,2). These lesions are characterized by cellular proliferation, associated ductal dilation, and cyst formation (3-5). They represent approximately 20% of all pancreatic neoplasms (6,7) and 5% of all pancreatic cystic lesions (3). IPMNs usually present after sixth decade of life (1). Incidental diagnosis of these lesions has increased due to higher frequency of imaging studies conducted for other reasons (3-5). IPMNs can be asymptomatic in 21–33% of cases (8). However, symptomatic cases usually result from pancreatic duct obstruction, manifesting as pancreatitis, chronic abdominal pain, or jaundice (1,9). A rare complication of IPMN is development of fistulas to adjacent organs, with duodenum being the most commonly affected organ in such cases (5,10-12).

The aim of this report is to present a rare case of pancreatoduodenal fistula secondary to an obstructive pancreatic stone in a patient with IPMN, highlighting diagnostic challenges, clinical presentation, and successful endoscopic management. This report aims to enhance awareness among clinicians about possibility of such rare complications, underscore the value of comprehensive diagnostic evaluations, and suggest effective management strategies for similar cases, particularly in elderly patients. Additionally, this publication seeks to contribute to existing literature by documenting a unique mechanism of fistula formation due to increased intraductal pressure caused by an obstructive pancreatic stone.

This report presents a case of an elderly patient with a pancreatoduodenal fistula secondary to an IPMN associated with an obstructive pancreatic stone at minor papilla, presenting with atypical symptoms. We present this case in accordance with the CARE reporting checklist (available at https://ales.amegroups.com/article/view/10.21037/ales-24-46/rc).

Case presentation

We present the case of an 82-year-old male patient with a medical history of hypertension, pulmonary fibrosis, and pancreas divisum. Five years ago, he was diagnosed a main duct IPMN (MD-IPMN) without signs of complications. On this opportunity, he presented lower extremity weakness without any other significant associated symptoms at Emergency Department. An initial neurological evaluation was performed, which yielded normal results. Laboratory tests revealed leukocytosis of 16,300/µL and elevated C-reactive protein (CRP) levels of 271 mg/dL. Liver function tests and other laboratory results were within normal ranges. Given the history of IPMN and elevated inflammatory markers, an abdominal magnetic resonance imaging (MRI) with gadolinium contrast was performed. MRI revealed a 25 mm MD-IPMN in the head of the pancreas with an impacted pancreatic stone obstructing minor papilla (Figure 1).

Figure 1 Magnetic resonance imaging and cholangiography revealed diffused pancreatic duct dilation (yellow arrows) with intracystic stone (blue arrow).

The patient’s case was discussed at a multidisciplinary hepatopancreatobiliary (HPB) surgery committee. Due to his frailty, decision was made to drain the biliary system but not to perform a biopsy, as he was not considered a candidate for pancreatic surgery under any circumstance. Endoscopic retrograde cholangiopancreatography (ERCP) was performed under general anesthesia. Endoscopic visualization revealed thick purulent mucinous secretion emanating from minor papilla and presence of an ulcer in second portion of duodenum (Figure 2). Endoscopic cholangiography confirmed presence of a fistulous tract connecting MD-IPMN, as seen on MRI, to ulcer in the second portion of duodenum, with a large pancreatic stone inside. Given these findings, a double pigtail plastic stent (7F-5 cm) was placed to facilitate cavity drainage. Procedure concluded without incidents (Figure 3). During his hospital stay, he received intravenous ceftriaxone and metronidazole. The patient’s recovery was uneventful, with improvement in inflammatory parameters and resumption of oral intake without issues. He was discharged 24 hours after ERCP with a 10-day course of moxifloxacin.

Figure 2 Endoscopic retrograde cholangiopancreatography: thick mucinous and purulent material is seen protruding from the minor papilla and ulcerated fistula (black arrows).

Figure 3 Insertion of a 7F-5 cm double pigtail plastic stent. Cholangiogram shows a pigtail stent inside dilated pancreatic duct.

At his first follow-up visit, 10 days post-discharge, patient showed a favorable clinical evolution, with further improvement in well-being and no reported complications. He resumed his normal life without limitations.

All procedures performed in this study were in accordance with the ethical standards of our institution and National Research Committee and with the Helsinki Declaration (as revised in 2013). Written informed consent for publication of this case report and accompanying images was not obtained from the patient or the relatives after all possible attempts were made. Our scientific committee, Comite Ético Cientifico of Clinica Santa Maria, has given us authorization for publication without informed consent.

Discussion

IPMNs are uncommon among pancreatic neoplasms, and fistulization is one of their rarest complications (5). Typically, IPMN complications include ductal dilation, acute or chronic pancreatitis, hemorrhage, abscesses, or perforation (5). Fistula formation occurs infrequently, in 1.9–6.6% of complicated IPMN cases (10,13), with primary sites being the duodenum (64%), common bile duct (56%), and stomach (17%) (11). Fistulas to adjacent structures can develop due to mechanisms such as direct invasion (usually by malignant lesions), elevated intraductal pressures, mechanical penetration, or secondary inflammation (5,10,11). In this case, an obstructive pancreatic stone at the minor papilla was the primary factor in increasing intraductal pressure, leading to a pancreatoduodenal fistula.

The uniqueness of this case lies in the presence of an obstructive pancreatic stone as the main contributor to elevated intraductal pressure, a phenomenon rarely documented in the literature. Although the most common mechanisms for fistula formation involve either tumor-induced obstruction or malignancy-driven invasion, an obstructive pancreatic stone as the sole factor is exceedingly rare. A review of the literature identified only a few IPMN cases associated with pancreatic stones (2,14), and in those, the stones were not the primary cause of obstruction. No cases of pancreatoduodenal fistula secondary to IPMN due to an obstructive pancreatic stone have been previously reported, highlighting the exceptional nature of this patient’s condition.

Management of pancreatic fistulas varies according to complexity. Small, uncomplicated fistulas may close spontaneously with medical management, often involving somatostatin therapy. However, complicated fistulas require invasive intervention, commonly managed endoscopically through placement of a pancreatic stent and/or pancreatic sphincterotomy (4). In this case, endoscopic management with pancreatic stenting allowed adequate drainage and resolution of infection, underscoring its efficacy even in complex presentations.

The clinical presentation was also atypical, as our patient’s primary symptom was lower extremity weakness—a rare presentation for IPMN complications, which more commonly include pancreatitis, abdominal pain, or jaundice (1,9). This underscores the importance of considering IPMN complications in differential diagnoses even when presenting symptoms are unusual.

In summary, this case highlights a unique and rare presentation of a pancreatoduodenal fistula due to an obstructive pancreatic stone, emphasizing the importance of awareness of this complication and the challenges in management, especially in elderly or frail patients.

This case report has certain limitations. First, as a single case, its findings cannot be generalized to the broader population with IPMN. Second, without long-term follow-up, the durability and long-term effectiveness of the endoscopic management cannot be fully assessed. Additionally, the absence of comparative studies limits our ability to evaluate whether alternative approaches might offer similar or better outcomes. These limitations indicate a need for further research to better understand and manage rare complications of IPMN.

Conclusions

The reported case illustrates rare occurrence of pancreatoduodenal fistula secondary to IPMN, with an obstructive pancreatic stone as primary determinant of increased intraductal pressure. Endoscopic management by placement of a pancreatic stent was effective resolving the condition. This case underscores the value of considering rare complications and atypical presentations in IPMN’s management, especially in elderly patients.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the CARE reporting checklist. Available at https://ales.amegroups.com/article/view/10.21037/ales-24-46/rc

Peer Review File: Available at https://ales.amegroups.com/article/view/10.21037/ales-24-46/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://ales.amegroups.com/article/view/10.21037/ales-24-46/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of our institution and National Research Committee and with the Helsinki Declaration (as revised in 2013). Written informed consent for publication of this case report and accompanying images was not obtained from the patient or the relatives after all possible attempts were made. Our scientific committee, Comite Ético Cientifico of Clinica Santa Maria, has given us authorization for publication without informed consent.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Bong JJ, Wang J, Spalding DR. Pancreatobiliary and pancreatoduodenal fistulae in intraductal papillary mucinous neoplasm of the pancreas: report of a case. Surg Today 2011;41:281-4. [Crossref] [PubMed]
2. Khneizer G, Reddy KM, Hammami MB, et al. Formation of Pancreatoduodenal Fistula in Intraductal Papillary Mucinous Neoplasm of the Pancreas Decreased the Frequency of Recurrent Pancreatitis. Gastroenterology Res 2019;12:43-7. [Crossref] [PubMed]
3. Aliyev V, Yasuchika K, Badawy A, et al. Pancreatico-gastric fistula: a rare complication of intraductal papillary mucinous neoplasm. JOP: J Pancreas 2017;18:362-4.
4. Patel A, Allen A, Kuwahara J, et al. Intraductal papillary mucinous neoplasm complicated by a gastropancreatic fistula. Radiol Case Rep 2018;14:320-3. [Crossref] [PubMed]
5. Estifan E, Farokhian A, Melki G, et al. Simultaneous pancreatico-enteric fistulae: a complication of pancreatic intraductal papillary mucinous neoplasm. Am J Gastroenterol. 2020;115:S757. [Crossref]
6. Sarr MG, Murr M, Smyrk TC, et al. Primary cystic neoplasms of the pancreas. Neoplastic disorders of emerging importance-current state-of-the-art and unanswered questions. J Gastrointest Surg 2003;7:417-28. [Crossref] [PubMed]
7. Allen PJ, D'Angelica M, Gonen M, et al. A selective approach to the resection of cystic lesions of the pancreas: results from 539 consecutive patients. Ann Surg 2006;244:572-82. [PubMed]
8. Brugge WR, Lauwers GY, Sahani D, et al. Cystic neoplasms of the pancreas. N Engl J Med 2004;351:1218-26. [Crossref] [PubMed]
9. Fong ZV, Fernández-Del Castillo C. Intraductal Papillary Mucinous Neoplasm of the Pancreas. Surg Clin North Am 2016;96:1431-45. [Crossref] [PubMed]
10. Kobayashi G, Fujita N, Noda Y, et al. Intraductal papillary mucinous neoplasms of the pancreas showing fistula formation into other organs. J Gastroenterol 2010;45:1080-9. [Crossref] [PubMed]
11. Zamora C, Sahel J, Cantu DG, et al. Intraductal papillary or mucinous tumors (IPMT) of the pancreas: report of a case series and review of the literature. Am J Gastroenterol 2001;96:1441-7. [Crossref] [PubMed]
12. Shishido Y, Mitsuoka E, Ito R, et al. Fistula formation into other organs secondary to intraductal papillary mucinous neoplasm of the pancreas: A case report and literature review. Medicine (Baltimore) 2023;102:e34288. [Crossref] [PubMed]
13. Ravaud S, Laurent V, Jausset F, et al. CT and MR imaging features of fistulas from intraductal papillary mucinous neoplasms of the pancreas to adjacent organs: A retrospective study of 423 patients. Eur J Radiol 2015;84:2080-8. [Crossref] [PubMed]
14. Yamada Y, Mori H, Hijiya N, et al. Intraductal papillary mucinous neoplasms of the pancreas complicated with intraductal hemorrhage, perforation, and fistula formation: CT and MR imaging findings with pathologic correlation. Abdom Imaging 2012;37:100-9. [Crossref] [PubMed]