Cholecystocolonic Fistula with Impacted Gallstone Presented as Proctitis

Abstract

Introduction Cholecystoenteric fistulas are rare, with incidence from autopsy series reported to be 0.1-0.5%. Often fistulas form due to repeated injury from cholelithiasis or cholecystitis. Cholecystoduodenal fistulas represent the majority of cases, with less than 20% found to have cholecystocolonic fistulas. Due to the large caliber of the colon, cholecystocolonic fistulas rarely present with complications such as gallstone impaction, gastrointestinal hemorrhage or proctitis. Here we report a rare case of a cholecystocolonic fistula leading to rectal gallstone impaction and subsequent proctitis. Case Presentation A 53 year-old male presented to our facility for 1 day of rectal pain. The patient had rectal bleeding with straining but was unable to defecate. CT of the abdomen with contrast on admission showed a 4.5 cm lamellated calcified structure in the rectum with wall thickening. Additionally, there was air from the hepatic flexure extending superiorly to a contracted gallbladder, indicating a possible fistula between the colon and the gallbladder. Of note, the patient had a colonoscopy 6 months prior with normal findings. The patient underwent a flexible sigmoidoscopy where upon entering the rectum a large calcified gallstone was encountered with endoscopic evidence of proctitis. Multiple attempts were made to capture the gallstone using a Raptor grasping device, a snare, a Roth net, and a mechanical lithotripsy but were unsuccessful. Subsequently the stone was maneuvered to the anal verge and was removed via a sponge stick and gentle traction. Two days later the patient underwent a colonoscopy where a cholecystocolonic fistula at the hepatic flexure was confirmed. The patient then underwent an exploratory laparotomy where the fistulous connection was found to have injured greater than 50% of the circumference of the hepatic flexure, hence a right colectomy was performed. Discussion The preoperative diagnosis of cholecystoenteric fistulas is only made in about 7.9% of cases. Failure to diagnose fistulas preoperatively could lead to an unexpected high risk procedure. Here, the patient's impacted rectal gallstone was removed endoscopically and the fistula was diagnosed preoperatively during colonoscopy. Endoscopy is a safe and effective modality for diagnostic and therapeutic purposes when a cholecystoenteric fistula is suspected.1897_A Figure 1. Impacted rectal gallstone1897_B Figure 2. Impacted rectal gallstone with endoscopic evidence of proctitis1897_C Figure 3. Endoscopic finding of cholecystocolonic fistula