Congenital anomalies of the biliary tree are frequently encountered in patients undergoing surgery for gallbladder stones and are a common cause of postoperative complications in these patients. Vesica fellea duplex or double gall bladder is a rare congenital malformation that results from embryonic dysgenesis of the hepatic antrum.1 Autopsy studies show an incidence of 1 in 4000 births, however, symptomatic cases are rare.1 Due to the rarity of the disease, these are often misdiagnosed preoperatively. We report a case of double gall bladder which was diagnosed as choledochal cyst type 6 on imaging and was found out to be a double gall bladder intraoperatively.
Case Report
A 67-year-old female with no known comorbidities presented to the outpatient clinic with complaints of pain right upper abdomen for the last 2 days. There was no associated history of fever/nausea/vomiting. Abdominal examination was unremarkable. Ultrasound abdomen revealed gall bladder stones with thickened walls suggestive of acute cholecystitis. Her biochemical profile showed leucocytosisand liver functions showed raised alkaline phosphatase (220 U/L) with normal bilirubin.
Because of elevated alkaline phosphatase, magnetic resonance cholangiopancreatography (MRCP) was performed which was reported as distended gallbladder filled with multiple stones and another cystic outpouching related to the cystic duct suggestive of type 6 choledochal cyst. The rest of the biliary anatomy was normal. Given these findings, patient was planned for laparoscopy and to proceed with cholecystectomyor excision of cyst/common bile duct with Roux En-Y hepaticojejunostomy.
On laparoscopy, the common bile duct was delineated and found to be normal. The gall bladder was unusually distended. Dissection was performed at the Calot’s triangle and to our surprisetwo separate cystic ducts were identified running parallel to each other accompanying a single cystic artery. (Figure 2) Both cystic ducts and artery were clipped separately and divided. Gall bladder was then dissected off the cystic plate using hook electrocautery. The cut section of the specimen showed two separate lumens of gallbladder covered in a common peritoneal lining with separate cystic ducts entering into each moiety (Type 2 double gall bladder). (Figure 2) After the surgery, the operative findings were discussed with the radiologist. The MRCP was reviewed again, which showed a likelihood of two cystic ducts, each entering into the distended gall bladder and the juxta gallbladder cystic outpouching suggestive of a double gallbladder .(Figure 3) The post-operative course was uneventful and the patient was discharged on postoperative day 1. Histopathology was suggestive of cholecystitis.
Discussion
Congenital malformations of the gall bladder can be either morphological or positional abnormalities. Double gall bladder is a rare morphological abnormality that results from incorrect differentiation of embryonic organs during the 5th to 6th week of gestation, when an additional bud arises from the hepatic diverticulum, leading to the formation of two separate gallbladders.2
The earliest description of a double gall bladder dates back to 31 BC, in a sacrificial victim of Emperor Augustus. Sherren in 1911, documented the first double gall bladder in a living human.3
Multiple classification systems for double gallbladder have been proposed based on anatomical features and the presence of associated anomalies. The first classification was given by Boyden et al in 1929, based on 20 reported cases.3 The two main groups included – Group 1 included bilobed gall bladders with single cystic duct – vesica fellea divisa and Group 2 included true gall bladder duplication – vesica fellea duplex.
Harlaftis et al in 1977 again classified duplex gall bladder into three groups as per the embryogenesis.Type 1 or split primordial group includes a single cystic duct draining into common bile duct. These are further divided into V-shaped or Y-shaped. Type 2 or accessory gall bladder group has more than one cystic duct into the common bile duct. They can be either H type or right and left trabecular type. Type 3 is a rare anomaly like triple gall bladder. Our case is a type 2 H type double gall bladder.
The anatomical location of the two moieties can vary. Most gallbladders share a common peritoneal coat and are usually adjacent to each other. However, completely separate gall bladders in different locations – intrahepatic or subhepatic have also been reported in the literature.
As per a report by Gadour et al. in 2021, there are around 57 cases of double gallbladder reported to date. There are a few reported cases of triple gallbladder also.4
There are no specific signs and symptoms associated with just presence of a double gall bladder. Symptoms are usually secondary to gallstones, cholecystitis or biliary pancreatitis. The differential diagnosis includes focal adenomyomatosis, Phrygian cap, choledochal cyst and GB diverticulum.
The finding may be commonly missed on a routine transabdominal ultrasound due to the rarity of disease and ultrasound being an operator-dependent investigation. Congenital anomalies of the gall bladder and biliary tract are associated with a higher incidence of biliary injuries post cholecystectomy and hence biliary anatomy should be properly defined in patients with high suspicion of such findings on an ultrasound. MRCP or CT cholangiography is the investigation of choice for the identification of double gall bladder preoperatively.5 We reviewed the MRCP retrospectively where two ducts entering into the gallbladder were identified which was missed by the radiologist. This clinical error can happen in such rare cases due to a lack of anatomical familiarity. An intraoperative cholangiogram or a laparoscopic ultrasound may also be used in cases of doubt intraoperatively.
The indications for surgery are similar to as in the presence of a single gall bladder with surgery reserved for patients with symptoms. Laparoscopic cholecystectomy is the treatment of choice, however, a low threshold for conversion to open surgery is advised in case of doubt.
Conclusion
Duplication of gall bladder although a rare congenital anomaly, requires special attention to the biliary and the vascular anatomy in cases of doubt. Surgeons should consider these anomalies while performing cholecystectomy to avoid post-cholecystectomy biliary injuries. A laparoscopic approach to double gall bladder is feasible and safe, however, should be performed with caution by a high-volume hepatobiliary surgeon.
References
- Singh JP. Duplication of the Gallbladder as an Operative Surprise: A Case Report with Review of the Literature. Merrett ND, editor. Case Reports in Surgery. 2021 Feb 11;2021:1–5.
- Vezakis A, Pantiora E, Giannoulopoulos D, Fontara S, Kontis E, Polydorou A, et al. A Duplicated Gallbladder in a Patient Presenting with Acute Cholangitis. A Case Study and a Literature Review. Ann Hepatol. 2019;18(1):240–5.
- Boyden EA. The accessory gall-bladder– an embryological and comparative study of aberrant biliary vesicles occurring in man and the domestic mammals. American Journal of Anatomy. 1926;38(2):177–231.
- Gadour E, Hassan Z, Hassan A. Y-Shaped Vesica Fellea Duplex Gallbladder Causing Acute Biliary Pancreatitis. Cureus. 13(4):e14676.
- Botsford A, McKay K, Hartery A, Hapgood C. MRCP imaging of duplicate gallbladder: a case report and review of the literature. Surg Radiol Anat. 2015 Jul 1;37(5):425–9.