Cholecystocolonic fistula preoperatively diagnosed by endoscopic ultrasound of the colon.

The patient was a 58-year-old woman. Gallbladder stones and occult blood in feces were detected during a physical check-up, then the patient was referred to Nagoya University Hospital. In this case the fistula was difficult to diagnosed by ultrasound and endoscopic ultrasound (EUS) of the upper intestinal tract because the gallbladder was filled with stones. Barium enema and endoscopic retrograde cholangiopancreatography did not reveal fistula. Curved-linear array EUS of the colon showed fistula.