Abstract
Duplication of the gallbladder is a rare entity. It is often appreciated at surgery and has a higher propensity for complications and conversion to open surgery. We report a case of laparoscopic recognition and removal of a duplicated gallbladder opening into the bile duct through separate cystic ducts, in a young male presenting with biliary colics. Both cystic ducts were clipped and divided, and cholecystectomy completed laparoscopically. Although uncommon, awareness of this anomaly may contribute to minimising iatrogenic bile duct injuries.
Introduction
Duplication of the gallbladder is a rare congenital anomaly. Although autopsy studies show an incidence of 1 in 4000, reports of symptomatic cases are rare. 1 The anomaly results from the division and formation of an extra gallbladder primordium during the embryonic period. 1 In true duplications, both gallbladders may share a common cystic duct or have their own duct. Anatomical variations of the extrahepatic biliary tree may contribute towards iatrogenic bile duct injuries (IBDI). Furthermore, a missed accessory gallbladder may result in recurrent symptoms after cholecystectomy.2,3 Laparoscopic cholecystectomy for double gallbladders has been previously reported.4–6 We report on a case of laparoscopic cholecystectomy for gallbladder duplication recognized intraoperatively.
Case presentation
A 41-year-old male presenting with recurrent biliary colics of 6 months was booked for a laparoscopic cholecystectomy. Physical examination was normal except for right upper quadrant tenderness, and liver biochemistry was normal. Abdominal ultrasonography reported a thick-walled gallbladder with gallstones. Laparoscopic cholecystectomy was commenced using a conventional 4-port technique. Dense peri-cholecystic omental adhesions were taken down (Figure 1). As dissection progressed around the cysto-hepatic triangle, it became apparent that there were two gallbladders (Figure 2) draining separately into the bile duct through separate cystic ducts. Both cystic ducts were clipped and divided and both gallbladders removed laparoscopically (Figure 3). The patient was discharged the following day after an uneventful recovery and remains well 3 years after surgery. Histopathology showed chronic cholecystitis in both gallbladders.

Dense omental adhesions around the gallbladder area.

Two separate gallbladders with two cystic ducts.

Surgical specimen of two gallbladders.
Discussion
The first description of a duplicated gallbladder was in a sacrificial victim of Emperor Augustus in 31 BC, and Boyden 1 was first to describe it and its variable anatomy in 1926. Sherren 7 documented the first case of a double gallbladder removed surgically in 1911. Since then, cases of double gallbladders and their laparoscopic removal have been documented, as summarised in Table 1.3–6,8,9–25
Summary of laparoscopic cholecystectomy on double gallbladders.
GB: gallbladder; LC: laparoscopic cholecystectomy; ERCP: endoscopic retrograde cholangiopancreatography; OIC: intraoperative cholangiography; MRCP: magnetic resonance cholangiopancreatography; USS: ultrasound scan; RUQ: right upper quadrant; CBD: common bile duct.
Duplication of the gallbladder has an incidence of approximately 1:4000 births. 1 The incidence in adults at postmortem and radiology is approximately 0.02% and 0.03%, respectively, with an equal distribution between genders.8,26 The true incidence is likely to be higher since only those who became symptomatic and are imaged or are detected during surgery are reported.
Morphological and positional anomalies of the gallbladder include multiple gallbladders, malformation, deformation, ectopias, intrahepatic position, and the presence of heterotopic mucosa. Gallbladder duplication is a morphological anomaly, variations of which are described by Gross, 27 Boyden, and Harlaftis classifications. The Harlaftis classification and its modification 26 categorize true duplication into H- and Y-shaped subtypes. The H subtype has two cystic ducts that open separately into the bile duct, while the Y subtype has two cystic ducts that join prior to entering the bile duct 28 Figure 4. The Y subtype is less likely to result in conversion to an open procedure than the H subtype.3,4

Classification of duplication of gallbladders.
Non-regression and persistence of supernumerary buds and accessory vesicles originating from the hepatic antrum during the fifth to sixth week of embryogenesis, 1 bifurcation of the cystic primordium and accessory cystic primordium 28 and formation of two separate cystic primordia from the bile duct 28 are mechanisms proposed for gallbladder duplication.
Gallbladder anomalies often go undetected on abdominal ultrasonography and in addition, may be mistaken for a choledochal cyst, gallbladder diverticulum or Phrygian cap. 4 Magnetic resonance cholangiopancreatography and, to a lesser degree, endoscopic retrograde cholangiopancreatography, though diagnostic, are not usually performed in patients with uncomplicated symptomatic cholelithiasis. 29 Where intraoperative cholangiography is routinely performed during cholecystectomy, it may reveal this anomaly, but there are no reports on its utility.30,31 As in our case, gallbladder duplication is mostly recognised intraoperatively during laparoscopic cholecystectomy.
Conclusion
This case illustrates the possibility of unexpectedly encountering rare anomalies of the biliary tract at laparoscopic cholecystectomy. Awareness of these anomalies and the knowledge of operative strategies help minimise the risk of iatrogenic bile duct injuries and reduce conversion rates. Imaging suggestive of a biliary tract anomaly should trigger a high index of suspicion for other biliary anomalies. The case also highlights how meticulous, careful dissection of the cysto-hepatic triangle, even in the absence of preoperative imaging or intraoperative cholangiographic recognition of an anomaly, ensures safe laparoscopic cholecystectomy.
Footnotes
Acknowledgements
The authors acknowledge all ward staff who took care of this patient.
Author contributions
Conceptualisation: D.S. and S.S.. Data curation: D.S. Formal analysis: D.S. and M.H.G. Methodology: D.S. and M.H.G. Project administration: D.S., M.H.G., and S.S. Visualisation: D.S., M.H.G., and S.S. Writing–original draft: D.S. and M.H.G. Writing–review & editing: D.S. and S.S.
Declaration of conflicting interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
Ethics approval
Our institution does not require ethical approval for reporting individual cases or case series.
Informed consent
Written informed consent was obtained from the patient(s) for their anonymised information to be published in this article.
Consent for publication
The patient has given her consent for the case report to be published. The written informed consent to publish this information was obtained from this patient.
