A case of double common bile duct visually detected only by cholangioscope

Double common bile duct is a rare congenital anomaly [1] [2] [3]. We report a case of a 53-year-old Japanese man who was incidentally diagnosed with a double common bile duct by cholangioscope examination. He developed mild acute cholecystitis and received antibiotics. Drip-infusion cholangiography-computed tomography demonstrated a filling defect in the common bile duct (CBD) ([Fig. 1 a]). Endoscopic retrograde cholangiography (ERC) showed a normal bile duct image ([Fig. 1 b]), and the patient was diagnosed with spontaneous passage of choledocholithiasis. However, bile cytology detected atypical cells and this patient was referred to our facility.

Fig. 1 The imaging findings detected no double common bile duct. a Drip infusion cholangiography-computed tomography. b Endoscopic retrograde cholangiography. Black arrow shows a ventriculoperitoneal shunt for hydrocephalus. c, d Endoscopic ultrasound. e Contrast-enhanced endoscopic ultrasound.

Contrast-enhanced endoscopic ultrasound showed no contrast echoic lesions in the cystic duct and gallbladder, and sludge was suspected, but the CBD was normal ([Fig. 1 c – e]). We performed cholangioscopy (SpyGlass-DSII; Boston Scientific, Marlborough, Massachusetts, USA) to rule out minimal biliary cancer because previous cytology suggested possible malignancy. The cholangioscopy incidentally showed a common bile duct divided into two lumens ([Video 1]). We inserted a guidewire from the contralateral lumen and visually recognized the crossed guidewire from the alternative lumen, which was evidence for a double common bile duct ([Fig. 2 a – c]). The cystic duct branched from one lumen of the double CBD. The cholangioscopy did not show any tumor, and biopsy specimens and bile cytology were negative for malignancy.

Video 1 A case of double common bile duct visually detected only by cholangioscope.

Fig. 2 The double common bile duct visually detected by the cholangioscope. a, b View of the confirmation using a guidewire. White arrow shows the crossed guidewire. c Schema of the double common bile duct and confirmation using a guidewire. Black line shows the septum of the double common bile duct. Red line shows the guidewire. Arrow shows the view of the cholangioscope in [Fig. 2 b].

This case is a type I double common bile duct according to Saito’s classification [4]. There had previously been only one report of a double common bile duct visualized on cholangioscopy by Kawakubo [5], but this is the first report of a double common bile duct without ectopic drainage of the bile duct. Surprisingly, no modality other than the cholangioscope could detect the double common bile duct. This finding indicates that type I cases might be more latent and prevalent. We hope that a greater number of cases will elucidate the epidemiology of the double common bile duct in future.

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• References

• 1 Fan X, He L, Khadaroo PA. et al. Duplication of the extrahepatic bile duct: a case report and review of the literatures. Medicine (Baltimore) 2018; 97: e9953
• 2 Kolli S, Etienne D, Reddy M el al. A review of double common bile duct and its sequelae. Gastroenterology Res 2018; 11: 1-4
• 3 Yamashita K, Oka Y, Urakami A. et al. Double common bile duct: a case report and a review of the Japanese literature. Surgery 2002; 131: 676-681
• 4 Saito N, Nakano A, Arase M. et al. [A case of duplication of the common bile duct with anomaly of the intrahepatic bile duct]. Nihon Geka Gakkai Zasshi 1988; 89: 1296-1301
• 5 Kawakubo K, Isayama H, Sasahira N. et al. Double common bile duct visualized by SpyGlass cholangioscopy. Endoscopy 2012; 44: 136-137