Biliary Colonic Fistula Formation in the Setting of Obstructive Cholelithiasis.

Biliary enteric fistulas are rare form of internal biliary fistula encountered in <1% of patients with biliary disease while cholecystocolic fistulas are even rarer with reported incidence of 0.06%-0.14% in patients undergoing cholecystectomy. We present a case of biliary colonic fistula that developed in the context of obstructive cholelithiasis, emphasizing a pathological process involving chronic inflammation due to gallstone with a gradual erosion into the surrounding structure. A high index of suspicion is required for diagnosis, given the presentation with nonspecific symptoms. Given the risk of imminent cholangitis, sepsis, and liver parenchymal damage, early treatment with cholecystectomy with the closure of the fistula is recommended.