Synonyms: None.

Prevalence: 2.5:10,000 discovered at autopsy. Over 200 cases reported in the literature.

Definition: Gallbladder duplication occurs when two separate gall bladder cavities develop, each with separate cystic ducts. See fig 1.

Etiology: Embryologic abnormality of biliary tract development with a persistence and development of a normal vestigial out pouching of the biliary tree⁹.

Pathogenesis: Unknown.

Associated anomalies: Increased incidence of forgut malformations and aberrant vasculature^2,3.

Differential diagnosis: see Table 1

Prognosis: Good.

Recurrence risk. Not known to be increased.

Management: Standard obstetrical care.

MESH Gallbladder -abnormalities BDE 0404 ICD9 751.69 CDC 751.640

* Address correspondence to William B. Sutter, MD Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, 21^st and Garland Ave, Nashville, TN 37232-2675. Ph 615-322-0999 Fax 615-322-3764

Introduction

We present the first reported case of a prenatal diagnosis of gallbladder duplication and a review of the literature.

Case report

A 34-year-old G₃P₂₀₀₂ was referred for a routine screening ultrasound at 24 weeks. The ultrasound demonstrated gallbladder duplication with no other detectable anomalies. A follow-up ultrasound at 28 weeks showed normal growth and again demonstrated gallbladder duplication. The mother was induced at 40 weeks and had an uncomplicated vaginal delivery.

Fig. 1: Gallbladder duplication at 24 weeks.

The baby boy weighed over 3500g with Apgars of 8 and 9 (1 and 5 minutes). The patient was admitted to normal nursery and discharged home 3 days post-delivery. A post-natal follow-up ultrasound confirmed gallbladder duplication and absence of other anomalies. The patient was seen in the pediatric clinic through one year of age without medical problems and was then lost to follow-up.

Discussion

Gallbladder duplication is a well-known entity with an incidence at autopsy reported of 2.5:10,000. Boyden"s classic description defines gallbladder duplication as an embryologic abnormality in biliary tract development resulting in two separate gallbladder cavities, each with a cystic duct. Boyden examined over 19,000 human cadavers finding only 5 cases of gallbladder duplication. Interestingly, duplication was found in 1 of 8 cats, 1 of 28 calves and 1 of 85 lambs. The first reported case in human subjects was noted in a sacrificial victim of the Emperor Augustus in 31 BC^2,10. A case of triple gallbladder has been reported as well¹¹. Several anatomic variations of gallbladder duplication have been described (fig 2)^2,4. Duplication is more common than bilobation¹.

Fig. 2: The four main types of gallbladder duplication. Top left: Double gallbladder with a Y-shaped cystic duct entering the common bile duct. Top right: Double gallbladder with independent cystic duct entering the common bile duct. Bottom left: The second gallbladder is connected by its own cystic duct in the left hepatic duct. Bottom right: The cystic duct of the duplicated gallbladder enters the right lobe of the liver to connect with the right hepatic duct.

Associated anomalies

Several anomalies have been associated with gallbladder duplication including forgut malformations and aberrant hepatic and mesenteric vessels^2,3. Sono­gra­phic distinction between types of duplications (i.e. anatomy of cystic ducts) and detection of aberrant vessels has not been reported in the literature.

Prior to ultrasound, gallbladder duplications often were diagnosed only at the time of surgery, but sonography has described several cases in children and adults⁵.

Differential diagnosis

The differential diagnosis of gallbladder duplication (Table I) from other right upper quadrant cystic lesions is difficult.

Table 1: Differential diagnosis of gallbladder duplication

• Gallbladder folds
• Choledochal cyst
• Gallbladder diverticulum
• Hepatic cyst
• Mesenteric cyst

In adults, the presence of stones and the observation of asymmetric contraction of the gallbladder can aid in differentiation of folds from duplication⁷. Differentiation in symptomatic patients, with hepatobiliary imaging also has been recommended⁶. Also, CT evaluation of the gallbladder and associated vascular anomalies is reported to aid in the diagnosis of gallbladder duplication³. In neonates, ultrasound remains the modality of choice.

Congenital hepatic cysts are rare (less than 2% occur in children less than 2 years old), and they usually occur in the anterior segment of the right lobe. Gallbladder folds are commonly transverse and therefore the appearance is different from the longitudinal division observed in this case. Choledochal cysts are not expected to lie along the gallbladder as in this case.

Prognosis

The prognosis for gallbladder duplication is good. Although several authors report increased risk of acute and chronic cholecystitis, cholesterolosis, papilloma, carcinoma, biliary cirrhosis and torsion, other reports did not confirm this increased risk^2-8.

Therefore, when gallbladder duplication is discovered in utero, the patient can be reassured as to the benignancy of the finding.

References

1. Boyden E.A. The accessory gallbladder. Am J Anat 1926;38:177-231.

2. Udelsman R. Congenital duplication of gallbladder associated with an anomalous right hepatic artery. Am J Surg 1985;149:812-815.

3. Nichols DM, Superior mesentric vein rotation: a CT sign of mid-gut malrotation. AJR 1983;141:707-8.

4. Ryrberg C.H. Gallbladder duplication. Acta Chir Scand 1960;119:36-44.

5. Granot E. Duplication of gallbladder associated with childhood obstructive biliary disease and biliary cirrhosis. Gastroenterology 1983;85:946-950.

6. McDonald K, Sonographic and Scintigraphic evaluation of gallbladder duplication. Clin Nucl Med 1986;11(10); 692-693.

7. Gioncy, Sonography of gallbladder duplication and differential condiderations. AJR 145;241-3, 1985.

8. Harlaftis N. Multiple gallbladders. Surg Gynecol Obstet 1977;145:928-934.

9. Gross RE. Congential anomalies of the gallbladder: a review of 148 cases with a report of double gallbladder. Arch Surg 32:131, 1936.

10. Jastrow M Jr. The liver as the seat of the soul. lr: Lyon, Moore, eds. Studies in the history of religions. New York, MacMillen 1912:160.

11. Kurzewg FT, Cole PA. Triplication of the gallbladder: review of literature and report of a case. Am Surg 1979;45:410.