Dear Editor, we present a case of a duplicated gallbladder (GB) with exceptionally
rare associated anomalies, along with the existing literature about this variant,
its anatomical categorization, and surgical implications. There are numerous varying
subtypes of GB duplication and their knowledge is essential for diagnosis and surgical
management.
The GB is known for its anatomical variations. Duplication of GB is one such rare
congenital entity, with incidence of 1 per 3,800 to 4,000 births.[1] Although it usually presents as an incidental finding associated with other congenital
anomalies, a preoperative diagnosis is important to prevent iatrogenic bile duct injuries
during cholecystectomy, especially in the present era of laparoscopic or minimal access
surgeries. Ultrasound (USG) is the preferred imaging modality because of its high
sensitivity and specificity.
A 1-year-old female child, diagnosed with ventricular septal defect (VSD), was referred
to the department of radiodiagnosis for USG abdomen, which revealed two elongated
anechoic cystic structures in GB fossa region, suggestive of duplication of GB ([Fig. 1]). Also, left renal pelvis was disproportionately dilated as compared with renal
calyces, with abrupt narrowing at the pelvic-ureteric junction (PUJ), suggestive of
PUJ obstruction. VSD was also demonstrated on USG and Doppler imaging ([Fig. 2]). Subsequently, magnetic resonance cholangiopancreatography (MRCP) was performed
which revealed two separate GBs opening into common cystic duct and left PUJ obstruction
was confirmed. Hepatobiliary iminodiacetic acid scan was also performed which confirmed
the presence of double GB. Final diagnosis of Y-shaped type (vesica fellea duplex)
duplication of GB with left-sided PUJ obstruction kidney was made.
Fig. 1 (A) Transabdominal ultrasound (USG) showing two elongated saccular structures of anechoic
content at the gallbladder fossa, reflecting duplicated gallbladder. (B) Coronal magnetic resonance cholangiopancreatography (MRCP) images showing two pear-shaped
structures in the gallbladder fossa suggestive of duplicated gallbladder with common
cystic duct draining into the common bile duct (CBD). Left-sided pelvic-ureteric junction
(PUJ) obstruction is also seen. (C, D) USG and Doppler images showing presence of ventricular septal defect.
Fig. 2 Serial static hepatobiliary iminodiacetic acid (HIDA) images in anterior, posterior
oblique views confirming the presence of duplicated gallbladder (GB).
The duplication of GB is a morphological anomaly. It occurs due to incorrect differentiation
or abundant division of embryonic organs during the 5th and 6th gestational week,
when the caudal bud of the hepatic diverticulum divides into different buds or outpouchings.
The later the single primordium divides, the less outright is the resulting duplication.
Consequently upon, a true duplication of GB occurs earlier in the gestation and involves
the existence of an accessory GB and two distinct cystic ducts.[2]
Among the several proposed classification systems, Boyden's system is used to classify
duplication of GB. The two main types of duplications are vesica fellea divisa (bilobed
GB) and vesica fellea duplex (true duplication), the latter being more frequent, with
two separate cystic ducts. However, the true duplication is subclassified into H-shaped
type which comprises two separate GBs and cystic ducts entering separately into the
common bile duct; and another Y-shaped type, where the two cystic ducts unite before
opening into the common bile duct.[3] Adding to our knowledge, cases of triple GBs have also been reported in the literature.[4]
The differential diagnosis includes GB fold, focal adenomyomas, Phrygian cap, intraperitoneal
fibrous (Ladd's) bands, choledochal cyst, pericholecystic fluid, and GB diverticulum.
Although clinical significance of double GB like association of gallstones, risk of
cancer, etc., is alike to those encountered in single GB, preoperative diagnosis is
important to avoid bile duct injuries during cholecystectomy.[1]
There have been sporadic case reports of several anomalies associated with double
GB including foregut malformations, aberrant hepatic, and mesenteric vessels.[5] However, none of them have reported the association with PUJ and VSD, which makes
this case even rarer[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15] ([Table 1]).
Table 1
Cases of duplication of gallbladder associated with other anomalies
|
Sl. no.
|
Author and year reported
|
Patient's age and gender
|
Associated anomalies
|
|
1.
|
Bailie et al, 2003
|
7 y, female
|
Heterotopic gastric mucosa
|
|
2.
|
Sasaki et al, 2005
|
69 y, male
|
Double gallbladder of the duodenal type
|
|
3.
|
Lefemine and Lazim, 2009
|
55 y, male
|
Traumatic neuroma
|
|
4.
|
Kawanishi et al, 2010
|
75 y, male
|
Well differentiated tubular adenocarcinoma
|
|
5.
|
Kachare et al, 2013
|
55 y, female
|
Ectopic thyroid
|
|
6.
|
Girish et al, 2013
|
3-day-old, male
|
Duodenal atresia
|
|
7.
|
Menon et al, 2013
|
4 y, male
|
Duodenal duplication cyst
|
|
8.
|
Gupta et al, 2016
|
2-day-old, male
|
Gastrointestinal atresia
|
|
9.
|
Gupta et al, 2016
|
12-day-old, male
|
Duodenal atresia
|
|
10.
|
Chamaria, 2016
|
9 y, male
|
Horse-shoe kidney
|
|
11.
|
Zhuang et al, 2020
|
61 y, male
|
Type I choledochal cyst
|
|
12.
|
Kumar et al, 2021
|
6 y, male
|
Type I choledochal cyst
|
USG remains the initial choice with high sensitivity and specificity. Contrast-enhanced
computed tomography, MRCP, and nuclear imaging are other modalities which can be used
to delineate the anatomy. Cholecystectomy is recommended in symptomatic patients;
however, surgery in asymptomatic patients remains controversial. Duplication of GB
is a rare biliary tract anomaly that should be recognized by the imaging experts to
serve as a roadmap for operating surgeon to prevent undesirable operative and postoperative
morbidity.
