Cholecystocolonic fistula as an uncommon cause of diarrhea: a case-report and review of the literature.

Bilio-enteric fistulization is the aberrant connection between the biliary and luminal digestive tracts. The cholecystocolonic fistula (CCF) is the second most common bilio-enteric fistula (comprising 20% of cases), after the cholocystoduodenal fistula (comprising 70% of all cases). A CCF may result from malignancy or more benign etiologies, such as gallstones, and is thought to arise from a chronic inflammatory cadence of tissue necrosis, tissue perforation, and fistula creation. The combination of chronic watery diarrhea, vitamin K malabsorption, and radiological evidence of pneumobilia in a patient with history of gallstone disease has been suggested as a pathognomonic triad of CCF. Here, we present a case of a 62-year-old woman exhibiting this triad, who was found to have a CCF as a result of chronic gallstone-related disease. Recognition of this rare etiology of chronic diarrhea can enhance clinicians' diagnostic appraisal and management of this common chief complaint.