Aberrant gallbladder situated beneath the left lobe of liver

Abstract

Background

Aberrant gallbladder beneath the left liver is a rare congenital anomaly that is found in 0.1–0.7 per cent of the population and causes confusion on imaging and at operation.Two such cases are presented.

Case outlines

A man of 83 yr was explored for obstructive jaundice due to a hilar tumour, but the gallbladder was ‘missing’. Exploration of a cystic mass to the left of the falciform ligament revealed a gallbladder attached to segment III of the liver. Laparotomy for gallstones in a woman of 70 yr failed to reveal the gallbladder until further dissection was carried out to the left of the falciform ligament. In each of these cases the cystic duct described a hairpin bend before joining the common hepatic duct on its right-hand side.

Conclusion

A left-sided gallbladder can be truly ectopic or may just appear so because the falciform ligament is aberrantly placed to the right. In either case preoperative imaging can be misleading, and a careful search is needed at operation. The incidence of disease seems no commoner than in orthotopic gallbladders.

Introduction

The gallbladder and its ducts form from the cavitation and coalescing of the epithelial cells from the primitive gut in relation to the liver outgrowth. As a result of aberration of this process, several congenital abnormalities of the gallbladder can occur: ¹ 1) Septate gallbladder, in which the septa may be transverse or longitudinal; 2) Double gallbladder with single or separate cystic ducts; 3) Accessory cystic ducts connecting the gallbladder with an intrahepatic duct in the liver bed; 4) Persistence of bile duct remnants in the left triangular ligament; 5) Intrahepatic gallbladder; 6) Gallbladder located beneath the left lobe of liver. There are four types of aberrant (ectopic) gallbladder: intrahepatic, transverse, retrodisplaced and left-sided, i.e. to the left of the falciform ligament. Sporadic reports of aberrant gallbladder beneath the left liver have come from all over the world but mostly from Japan ²; there are no previous reports from India. The detection of an aberrant gallbladder has assumed a new dimension as laparoscopic cholecystectomy has become the standard operative procedure for gallstones.

We report two cases of aberrant gallbladder situated under the left liver and review the world literature.

Case Reports

Case no. 1

An 83-year-old male diabetic presented with a 4 week history of painless progressive jaundice and continuous dull ache in the right hypochondrium associated with pale stools and dark urine. There was loss of appetite and weight. Clinical examination only revealed deep jaundice and a smooth non-tender hepatomegaly (10 cm).

The patient was anaemic (haemoglobin 9.0 g/dl) with a raised serum bilirubin (0.2083 mmol/L) and alkaline phosphatase (14 KA units/L).

Ultrasonography showed an enlarged liver with dilated intrahepatic ducts; the gallbladder and common bile duct (CBD) were not visualised. ERCP showed a normally placed gallbladder with biliary obstruction at the level of the porta hepatis. PTC confirmed a complete block at the porta hepatis.

At operation the liver was enlarged and the gallbladder was absent from its normal position. A large cystic lump was felt medial to the falciform ligament. It was explored by dividing the falciform ligament and was found to be an aberrant gallbladder under the left liver. It was attached to segment III of the liver, but the cystic duct was joining the common hepatic duct on the right side at the end of a hairpin bend. The cystic artery was arising normally from the right hepatic artery.

An irresectable cicatrising tumour was present at the porta hepatis, and the CBD was 3–4 mm in size below this point. Cholecystoduodenostomy was carried out but there was no flow of bile. External biliary drainage was therefore established by cannulation of the segment V duct.

Case no. 2

One of the authors (HSS) was requested to assist a surgeon who was unable to locate the gallbladder in a 70-year-old woman in whom ultrasound scan had shown cholelithiasis with acute inflammation of the gallbladder. The gallbladder was absent from its normal location. Exploration medial to the falciform ligament under the left liver revealed the gallbladder attached to a shallow fossa in the liver. The cystic duct joined the common hepatic duct on the right side after making a hairpin bend, and the cystic artery originated from the right hepatic artery. Cholecystectomy was undertaken.

This patient had presented with recurrent pain in the right upper abdomen for two months. The radiologist did not comment on the ectopic location of the gallbladder when reporting the ultrasound scan.

Discussion

An aberrant gallbladder situated under the left liver, medial to the falciform ligament, was first described by Hochstetter ³ in 1886 and was termed ‘left-sided gallbladder’. Over the last 112 years, 110 more cases have been reported. The method of detection was by anatomical dissection until the 1930s, by cholecystography and/or laparotomy during the 1940s and 1950s and by laparoscopy more recently (Table 1). During this period only five cases of diseased aberrant organs were found (Table 2), all the rest being chance findings.

Table 1. Method of detection of aberrant gallbladder situated under the left liver (left sided gallbladder).

1886	Hochstetter 3	Anatomical dissection
1902	Deve 20	Anatomical dissection
1902	Kehr 21	At laparotomy
1912	Walton 22	Anatomical dissection
1926	Harris 23	Anatomical dissection
1930	Drechsel 24	Anatomical dissection
1932	Hartung 25	Cholecystography – functioning gallbladder
1950	Mayo	Laparotomy, floating gallbladder
1951	Nemours et al27	Cholecystography showed excessive mobility of gallbladder
1951	Bleich etal28	Cholecystography-functioning gallbladder
1953	Etter 4	Cholecystography-functioning gallbladder
1955	laccarino & Idone 29	Cholecystography, laparotomy confirmation & cholecystectomy of normal gallbladder
1959	Gondra et al30	Cholecystography – functioning gallbladder
1960	Ergun 31	Cholecystography – functioning gallbladder
1960	Mizray 32	Cholecystography – functioning gallbladder
1961	Jona etal33	Cholecystography – functioning gallbladder
1964	Newcombe & Hanley	Laparotomy in jaundiced patient
1987	Ozeki etal8	At laparotomy
1990	Benzo etal35	Detected by hepatobiliary scintigraphy
1990	Benzo et al5	Detected by hepatobiliary scintigraphy
1992	Ikoma etal11	At laparotomy
1995	Ogawa et al18	At laparotomy
1996	Fujita etal16	Detected at laparoscopy

There are other reports of aberrant gallbladder situated under the left liver in the non-English literature ³⁷,³⁸,³⁹,⁴⁰ with little clinical detail available from the abstracts reviewed.

Table 2. Aberrant gallbladder situated under the left lobe of liver with disease.

Year/author	Disease/detection	Treatment
1948: McGowen etal41	Giardia lamblia infection, laparotomy	Cholecystectomy
1950: Mayo and Kendrick 26	Gangrenous cholecystitis	Cholecystectomy
l993:Schiffino et al19	Cholecystitis, detected on laparoscopy	Cholecystectomy (laparoscopic)
1988: Kinoshita etal42	Cholelithiasis	Cholecystectomy
l998:This study	1. Detected at laparotomy for mechanical jaundice	1. Cholecystoduodenostomy
	2. Cholelithiasis detected by ultrasonography, left gallbladder detected by laparotomy	2. Cholecystectomy

Anatomical descriptions of aberrant gallbladders have uniformly mentioned a sharply curving cystic duct entering the common duct on its right side and making a hairpin bend. In oral cholecystography done for investigation of pain, the left-sided gallbladder was always found to be functioning. Since it could be missed on a small x-ray film, a full-size film was recommended for cholecystography ⁴.

An aberrant gallbladder situated under the left lobe of liver may develop in two ways. First, the gallbladder develops from an hepatic diverticulum at its normal place then migrates to the left of falciform ligament and becomes attached to the under-surface of the left liver. This migration explains the entry of the cystic duct on the right side of the hepatic duct, as described in this and most other studies. Second, a left-sided gallbladder may develop directly from the left hepatic duct ⁵ accompanied by failure of the development of a normal gallbladder on the right side ⁶. Here the cystic duct enters the common duct directly on the left side. Third, some left-sided gallbladders have been explained by Nagai and colleagues who found the anomaly associated with a right-sided falciform ligament in 3 of 1621 patients (0.2%) at operation ⁷; another 15 examples of this association have been described ²,⁸,⁹,¹⁰,¹¹,¹². The suggested explanation is that during early fetal growth to 6 mm size, both right- and left-sided umbilical ligaments exist. By 7 mm embryo size the right side normally atrophies and the left side becomes dominant ¹³,¹⁴. In rare instances the left ligament atrophies and a right ligament becomes dominant (in 0.1–0.7%) ⁸,¹⁵,¹⁶,¹⁷. In such patients the gallbladder is situated at the normal site but to the left of a right-sided falciform ligament, so it appears aberrant beneath the left lobe of liver. This anomaly should not be confused with a true left-sided gallbladder situated medial to a normal falciform ligament. Information on the falciform ligament is not usually available in reports, but in each of the cases the falciform ligament was normally placed.

There are several therapeutic implications of an aberrant gallbladder beneath the left lobe of liver. It may be associated with the anomalies of the intrahepatic portal vein or the cystic duct ¹⁸ or with an accessory liver ¹¹. Aberrant gallbladders are prone to similar diseases as their normally sited counterparts, including cholelithiasis, polyps and empyema (Table 2) ⁸. Seven diseased organs have been reported among the 110 aberrant gallbladders situated under the left lobe of liver. Awareness of the anomaly is needed in planning operations. In our second case the surgeon failed to identify, via a right subcostal incision, an empyma of an aberrant gallbladder situated under the left lobe of liver, while in the first case a large mucocele was missed on ultrasonography and again at laparotomy until the falciform ligament was divided. ERCP in this patient had been unhelpful. A midline incision is appropriate for an aberrant gallbladder situated under the left lobe of liver, although laparoscopy may also be appropriate with the precaution of a retrograde dissection to demonstrate the relation of the cystic duct to the CBD ¹⁹.

Awareness of the anomaly is clearly necessary for successful treatment. Fifteen Japanese reports of an aberrant gallbladder situated beneath the left liver are available compared with 27 reports from other countries. Either the condition is commoner in the Japanese, or Japanese surgeons have become aware of the condition and detect it more often.