Cholecystoduodenal Fistula Masquerading as a Duodenal Mass

Abstract

Introduction: We report a case of a complicated gallstone disease with cholecystoduodenal fistula (CCDF) masquerading as a duodenal mass. Case Report: A 78-year-old man with multiple medical comorbidities presented with hematemesis shortly after starting warfarin for atrial fibrillation. Initial EGD reported a mass with large clot in the proximal duodenum. CT and MRI imaging showed an apparent 8.6-cm mass arising from the duodenum or gallbladder with extension into the inferior right liver. Thrombosis was present in the portal vein. A 1.7-cm portocaval lymph node was also noted. The CBD was mildly dilated at 1.0 cm with low-grade elevation of liver tests. Diagnostic laparoscopy with biopsy of the mass was inconclusive. He was subsequently transferred to our facility for evaluation of suspected neoplastic disease. Repeat EGD revealed a 4-5 cm diverticular-like cavity in the posterior duodenal bulb with inflammatory change, scar, and apparent fistulous tracts within. EUS revealed a 1.7-cm poorly defined mixed echogenic process in the periduodenal space communicating with the diverticulum. Biopsies and FNA showed inflammatory change. EUS revealed an incidental <1 cm distal CBD stone. ERCP confirmed stone with no stricture. The cystic duct was seen to partially fill with contrast and air was seen in the gallbladder. Percutaneous biopsy of the questionable right hepatic process was also negative. Based on the above it was determined that findings were consistent with complications from CCDF and not a malignant process. The patient was managed conservatively. Follow-up CT at 4 months showed improving pericholecystic soft tissue inflammatory change with no detectable enteric fistula. Discussion: Complications from gallstone disease can present in a variety of ways and may rarely masquerade as a malignant process. Fistulas complicate 2-3% of all cases of gallstone associated cholecystitis. CCDF is the most common type occurring in nearly two-thirds of cases. The mechanism of formation is thought to be a result of pericholecystic inflammation that leads to the development of adhesions between the biliary and enteric tract. Pressure necrosis by the gallstone results in fistula formation. Many patients are asymptomatic; however abdominal pain, gastric outlet obstruction (Bouveret syndrome), intestinal obstruction (gallstone ileus), biliary obstruction (Mirizzi syndrome), bleeding, or infection may occur. Fistulas may be challenging to detect on imaging and may be unsuspectedly found during endoscopy or intra-operatively. Although surgery may be needed, expectant management may be appropriate in the large subset of high-risk patients without progressive clinical sequelae.