Cholecystoenteric fistula following cholecystectomy: a rare complication case report

Introduction

Cholecystoenteric fistulas (CEFs) are rare complications of chronic biliary disease, occurring in 3–5% of patients with cholelithiasis (1). The most frequently involved segment is the duodenum (75%), followed by the colon (8–26%) (2). CEFs arise due to chronic inflammation and pressure necrosis, leading to an abnormal connection between the gallbladder and the adjacent gastrointestinal tract (3).

Patients with CEFs may present with nonspecific symptoms, including abdominal pain, nausea, vomiting, diarrhoea, or weight loss. The presence of chronic diarrhoea in CEFs is attributed to bile acid malabsorption and bypassing of enterohepatic circulation (4). Diagnosis is challenging, as symptoms often mimic other biliary and gastrointestinal disorders.

Preoperative detection of CEFs remains difficult, with a reported diagnostic accuracy of only 8–17% despite advances in imaging techniques (5). Computed tomography (CT) and magnetic resonance imaging (MRI) play a pivotal role in identifying pneumobilia, ectopic gallstones, and abnormal biliary-enteric communication. Endoscopic techniques, such as endoscopic retrograde cholangiopancreatography (ERCP), provide both diagnostic and therapeutic options for select cases.

We report a rare case of a CEF discovered in a patient presenting with altered bowel habits, emphasizing the role of imaging and histopathological confirmation in establishing the diagnosis. We present this article in accordance with the CARE reporting checklist (available at https://acr.amegroups.com/article/view/10.21037/acr-24-284/rc).

Case presentation

A 51-year-old male presented with a 2-week history of intermittent abdominal colic and altered bowel habits. He denied fever, jaundice, weight loss, or haematochezia. His medical history included an open cholecystectomy performed in 2007 for cholelithiasis. There was no family history of gastrointestinal malignancy.

On clinical examination, the patient appeared well and hemodynamically stable. Abdominal examination revealed a soft, non-tender abdomen without palpable masses. Laboratory investigations showed normal haemoglobin levels (14.5 g/dL), normal liver function tests, and carcinoembryonic antigen (CEA) levels within the normal range.

Upper gastrointestinal endoscopy [oesophagogastroduodenoscopy (OGDS)] revealed antral gastritis, while colonoscopy findings were unremarkable. However, contrast-enhanced CT of the abdomen showed pneumobilia, cholelithiasis, and a fistulous tract between the gallbladder remnant and the transverse colon. The presence of pneumobilia in the absence of recent biliary instrumentation further supported the diagnosis of a biliary-enteric fistula.

Surgical exploration was undertaken. Intraoperatively, extensive adhesions were noted at the previous cholecystectomy site. A fistulous communication between the gallbladder remnant and the transverse colon was identified as shown in Figure 1: fistulous tract between gallbladder remnant and transverse colon, and in Figure 2: intraoperative image demonstrating cholecystocolonic fistula with dense adhesions around gallbladder remnant.

Figure 1 Fistulous tract between gallbladder remnant and transverse colon.

Figure 2 Intraoperative image demonstrating cholecystocolonic fistula with dense adhesions around gallbladder remnant.

The patient underwent completion cholecystectomy and segmental colectomy with primary anastomosis.

Histopathological examination of the resected specimen confirmed chronic inflammatory changes and fibrosis at the fistulous site, validating the diagnosis. The postoperative course was uneventful, with the patient resuming oral intake on day 3 and being discharged on day 5.

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration and its subsequent amendments. Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Discussion

CEFs represent an uncommon but clinically significant complication of chronic biliary disease, occurring in approximately 3–5% of patients with cholelithiasis (1). These fistulas develop as a consequence of prolonged inflammation, leading to necrosis and the erosion of the gallbladder wall into an adjacent gastrointestinal structure. The duodenum is the most commonly affected site, accounting for nearly 75% of cases, while the colon is involved in approximately 8–26% of cases (2). CEFs, such as the one reported in this case, are less frequently encountered but present with distinct clinical features that necessitate a high degree of clinical suspicion for diagnosis.

The pathogenesis of CEFs is largely attributed to recurrent gallstone disease, which induces chronic cholecystitis and subsequent formation of a fistulous connection. Other etiological factors include peptic ulcer disease, malignancies, and inflammatory conditions such as Crohn’s disease (4). In rare cases, prior surgical interventions, such as cholecystectomy, can lead to the persistence of gallbladder remnants, which may become the site of chronic inflammation and eventual fistulisation. The presence of a post-cholecystectomy CEF, as observed in our patient, is particularly unusual and underscores the need for vigilance in patients with a history of biliary surgery who present with atypical symptoms.

Patients with CEFs may experience a wide range of clinical symptoms, many of which are nonspecific and often mimic other gastrointestinal or biliary disorders. The most characteristic symptom is chronic diarrhoea, which results from the direct entry of bile into the colon, bypassing the normal enterohepatic circulation. This leads to excessive bile salt exposure in the colon, which has a detergent effect on colonic mucosa, causing irritation and increased stool frequency. Other symptoms may include abdominal pain, nausea, vomiting, weight loss, and dyspepsia, though these are not specific to CEFs. Some patients remain asymptomatic, leading to incidental diagnosis during imaging or surgical exploration. A pathognomonic triad—pneumobilia, chronic diarrhoea, and vitamin K malabsorption—has been linked to cholecystocolonic fistulas (6).

The preoperative diagnosis of CEFs is notoriously challenging, as many cases are identified intraoperatively. Imaging plays a crucial role in detection, with CT being the most valuable modality for identifying key diagnostic features such as pneumobilia, ectopic gallstones, and the direct visualization of a fistulous tract (6). Pneumobilia, the presence of air in the biliary tree, is considered a hallmark radiologic finding and should raise suspicion for a CEF, particularly in the absence of recent biliary instrumentation or interventions. Other imaging techniques, such as magnetic resonance cholangiopancreatography (MRCP) and ERCP, can further delineate the biliary anatomy, with ERCP providing both diagnostic and therapeutic benefits in selected cases (7). In our patient, CT was instrumental in establishing the diagnosis, revealing pneumobilia and an abnormal communication between the gallbladder remnant and the transverse colon, which strongly suggested a CEF. Radiological studies remain a crucial modality in diagnosing cholecystocolic fistulas (8).

Despite advances in diagnostic imaging, many cases remain undiagnosed until surgical intervention. Colonoscopy, although useful for evaluating colonic pathology, may not always detect a fistulous opening, as the mucosal defect can be obscured by inflammation or may not be readily visible due to the angle of insertion. In our patient, colonoscopy was unremarkable, further emphasizing the diagnostic difficulty associated with CEFs and highlighting the importance of multimodal imaging in these cases.

The management of CEFs depends on the patient’s clinical status, the severity of symptoms, and the extent of bowel involvement. Surgical intervention remains the definitive treatment, particularly in symptomatic patients or those with complications such as gallstone ileus, recurrent infections, or suspected malignancy. The standard operative approach typically involves cholecystectomy and fistula closure, with laparoscopic techniques increasingly favoured due to their lower morbidity and comparable outcomes to open surgery. In cases where the colon is significantly involved, as in our patient, segmental colectomy with primary anastomosis may be necessary to prevent long-term complications such as chronic inflammation, persistent infection, or neoplastic transformation (9).

The decision between a one-stage and two-stage procedure depends on the patient’s stability and the severity of the inflammatory process. In hemodynamically stable patients with minimal contamination, a single-stage procedure involving cholecystectomy, fistula excision, and bowel resection with primary anastomosis is preferred. In critically ill patients or those with extensive sepsis, a two-stage approach with initial fistula diversion and later definitive repair may be required. Our patient underwent a single-stage procedure, with completion cholecystectomy and segmental colectomy followed by primary anastomosis, resulting in an uneventful recovery (10).

Histopathological confirmation of the fistula is crucial for establishing the diagnosis and ruling out malignancy, as neoplastic transformation of the fistulous tract has been reported in rare cases. In our case, histological examination of the resected specimen confirmed chronic inflammation and fibrosis at the site of fistulisation, which validated the preoperative imaging findings. The absence of dysplasia or malignancy provided further reassurance regarding the long-term prognosis.

Postoperative outcomes for surgically treated CEFs are generally favourable, with a low recurrence rate when the entire fistulous tract is excised. However, long-term follow-up is necessary, particularly in cases involving the colon, due to the potential for persistent gastrointestinal symptoms or alterations in bowel function. In our patient, no postoperative complications were observed, and the patient was discharged in stable condition five days after surgery. Postoperative complications may sometimes mimic neoplastic processes, especially in patients with previous biliary surgeries (11).

This case underscores the importance of considering CEFs in the differential diagnosis of patients with a history of gallstone disease or cholecystectomy who present with chronic gastrointestinal symptoms, particularly diarrhoea. Clinicians should maintain a high index of suspicion, especially when imaging reveals pneumobilia or ectopic gallstones. The case also highlights the role of histopathological confirmation in reinforcing the diagnosis and guiding management. Surgical resection remains the mainstay of treatment, and the increasing adoption of minimally invasive techniques is likely to improve outcomes in these patients. Unexpected development of biliary-colonic fistulas following laparoscopic cholecystectomy has also been reported.

Given the rarity of post-cholecystectomy CEFs, this case contributes valuable insights into the diagnostic and therapeutic considerations of this entity. It also emphasizes the need for an integrated diagnostic approach, incorporating clinical suspicion, imaging, and histological analysis, to ensure accurate diagnosis and appropriate management.

Conclusions

CEFs are rare but significant complications of chronic biliary disease. Preoperative diagnosis remains challenging despite advances in imaging modalities. High clinical suspicion and thorough imaging evaluation are essential for timely intervention. Surgical management, including cholecystectomy and fistula closure, remains the mainstay of treatment. Involvement of the colon necessitates colectomy with anastomosis to ensure complete resolution. Histopathological confirmation is invaluable in validating the diagnosis.

Acknowledgments

The study was conducted using resources provided by the authors and their affiliated institutions.

Footnote

Reporting Checklist: The authors have completed the CARE reporting checklist. Available at https://acr.amegroups.com/article/view/10.21037/acr-24-284/rc

Peer Review File: Available at https://acr.amegroups.com/article/view/10.21037/acr-24-284/prf

Funding: None.

Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://acr.amegroups.com/article/view/10.21037/acr-24-284/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 the institutional and/or national research committee(s) and with the Helsinki Declaration and its subsequent amendments. Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

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/.

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