Double Common Bile Duct.

A 73-year-old woman underwent esophagogastroduodenoscopy for the first time for screening purposes. It revealed an opening of the lesser curvature of the stomach from which yellowish brown fluid, which was determined to be bile, was flowing out (Picture 1, arrow). Computed tomography showed two common bile ducts: one drained into the duodenum at the site of the papilla and the other into the stomach (Picture 2, arrow). She was diagnosed with double common bile duct (DCBD). DCBD is a rare congenital anomaly with varying morphological patterns that is clinically important for two reasons (1,2).

Picture 1.

Picture 2.

First, DCBD may increase a patient's cancer risk. A bile drainage route other than the conventional route is called an accessory common bile duct (ACBD). Organs with an increased cancer risk depend on the outflow site of the ACBD. Physicians should keep the increased risk of concomitant gastric and pancreatobiliary cancers in mind and maintain a high index of suspicion when encountering patients with DCBD.

Second, the preoperative diagnosis of DCBD is difficult. However, when these patients undergo surgery, the ACBD may be misidentified (e.g., as a cystic duct), leading to complications.

The authors state that they have no Conflict of Interest (COI).