Couinaud Type A communicating accessory bile duct: report of a case.

BACKGROUND Communicating accessory bile ducts are defined as ducts that communicate between major biliary channels but do not drain individual segments of the liver. The Couinaud Type A communicating accessory bile duct is a rare anomaly where an aberrant duct connects the right main hepatic duct to the common hepatic duct without segmental drainage. There are very few reports of this anomaly in the literature to date. CASE PRESENTATION A 75-year-old male who died of ischemic heart disease donated his body for cadaveric dissection, which included careful attention to the anatomy of the hepatic hilum. During dissection, it was found that the right hepatic duct was duplicated and an accessory duct drained directly into the common hepatic duct. Although rare and difficult to visualize even with modern preoperative imaging techniques, sound knowledge of this rare anatomic variation is imperative to avoid inadvertent intraoperative biliary injuries which can lead to severe morbidity. CONCLUSIONS An aberrant bile duct from the right hepatic duct to the common hepatic duct (Couinaud Type A) is an uncommon accessory bile duct that one must be aware of when performing complex hepatobiliary procedures such as right liver resection for living-related donation. Detailed preoperative imaging and careful dissection with anticipation of anomalous anatomy are of the utmost importance for the safe conduct of hepatic surgery.