Cholecystoappendiceal Fistula From Appendiceal Adenocarcinoma Requiring a Right Hemicolectomy With Cytoreduction and Hyperthermic Intraperitoneal Chemotherapy.

Bilioenteric fistulae are rare and difficult to manage complications of chronic cholecystitis. While cholecystoduodenal and cholecystocolic fistulae are more common, a cholecystoappendiceal fistula is an extremely rare finding. We report the presentation and operative management of a 59-year-old male with cholecystoappendiceal fistula and associated abscess in the gallbladder fossa. The patient was appropriately resuscitated, the abscess drained by interventional radiology, and after a complete workup, underwent a laparoscopic appendectomy and cholecystectomy. Pathology revealed moderately differentiated appendiceal adenocarcinoma requiring a right hemicolectomy with cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC). He has recovered well postoperatively with no complications. This case highlights the importance of having a very high index of suspicion for underlying malignancy when managing a fistula of any kind. To the best of our understanding, this is only the second reported case of a cholecystoappendiceal fistula.