This case report describes an unusual case of a Phrygian cap (septate gallbladder) that mimicked a choledochal cyst. A 52-year-old male presented with right upper quadrant pain and was found to have an irregular hyperechoic mass in the gallbladder on ultrasound. CT and MRI suggested a choledochal cyst but MRCP revealed a septate gallbladder (Phrygian cap). At surgery, a septate gallbladder with stones was found but the common bile duct was normal. Phrygian cap is a common gallbladder anomaly that is usually asymptomatic but can be mistaken for other pathologies on imaging. Thorough preoperative imaging like MRCP is important to identify anatomical variations

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CASE REPORT
PHRYGIAN CAP MIMICKING A CHOLEDOCHAL CYST:
AN UNUSUAL CASE REPORT AND REVIEW OF
LITERATURE
Anilkumar VR, Narayana Subramaniam, Ganesh Hegde
1. Dr. Anilkumar VR, Associate Professor, General Surgery, M.S. Ramaiah Medical
College and Hospital, Bangalore, India
2. Dr. Narayana Subramaniam, Resident General Surgery, M.S. Ramaiah Medical
College and Hospital, Bangalore, India
3. Dr. Ganesh Hegde, Assistant Professor, General Surgery, M.S. Ramaiah Medical
College and Hospital, Bangalore, India
ABSTRACT
Major gallbladder and associated biliary malformations are an uncommon entity – incidence varies,
but the largest study conducted showed an incidence of around 0.15%. They are of great consequence
to surgeons as they may be associated with complex malformations in the extra-hepatic biliary tree
and its blood supply, making surgery difficult and dangerous. With intra-operative diagnosis being the
only viable option, a thorough knowledge of anatomical variations, the differential diagnosis on
imaging and a high index of suspicion is required to avoid intra-operative complications and their
significant associated morbidity. This article discusses a case of septate gall bladder (known as
‘Phrygian cap’) mimicking a choledochal cyst. It also discusses the difficulty in pre and peri-operative
diagnosis and management of biliary diseases.
KEY WORDS: Choledochal Cyst, gallbladder, Phrygian cap, biliary diseases.
INTRODUCTION
Gallbladder and associated biliary
malformations are an uncommon entity –
incidence varies, but the largest study
conducted showed an incidence of around
0.15%1
. Although asymptomatic, they may
also be associated with other systemic
malformations. Biliary malformations are
of great consequence to surgeons as they
may be associated with complex
malformations in the extra-hepatic biliary
tree and its blood supply, making surgery
difficult and dangerous2
. Pre-
cholecystectomy imaging with modalities
like MRCP has been employed only in a
setting of suspected common bile duct
stones in order to plan for a concurrent
common bile duct exploration3
, however
this has not been shown to be justified in
all patient of suspected to have common
bile duct stones, only those with specific
risk factors4
.
With intra-operative diagnosis being the
only viable option, a thorough knowledge
of anatomical variations, the differential
diagnosis on imaging and a high index of
suspicion is required to avoid intra-
operative complications and their
significant associated morbidity. This
article discusses a case of septate gall
bladder (known as ‘Phrygian cap’)
mimicking a choledochal cyst. It also
discusses the difficulty in pre and peri-
operative diagnosis and management of
biliary diseases.
Case report

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A 52 year old male presented to our
hospital with a history of intermittent pain
in the right upper abdomen since 6
months, continuous in nature, moderate in
severity with no radiation in site. He also
had frequent complaints of dyspepsia and
pain was aggravated around 1 hour after
food intake. He had no history of jaundice
or fever. He had no similar complaints
prior, no co-morbidities and was on no
medications. He reported that he had a
sedentary lifestyle, no history of smoking
or alcohol intake.
On examination, he was overweight, with
a body mass index of 27. He was not
jaundiced. Barring mild tenderness in the
right hypochondrium, his abdominal
examination was unremarkable. Bowel
sounds were normal. Routine blood counts
and liver function tests were normal and
viral serology was negative.
Ultrasonography of the abdomen showed
an irregular, hyperechoic mass that
appeared to be continuous with the lumen
of the gallbladder. However there was no
intrahepatic biliary radical dilatation.
Contrast enhanced computerized
tomography was performed for further
delineation of the mass, which showed a
cystic mass measuring 47x35mm
occurring along the course of the cystic
duct, suspected to be a choledochal cyst.
No contrast enhancement of the mass was
appreciated. For further clarity a magnetic
resonance cholangiopancreaticography
was performed, which showed
cholelithiasis with chronic fibrosis of the
gall bladder. No abnormality of the
common bile duct was noted.
Patient was planned for an open
cholecystectomy with a common bile duct
exploration if required. Intra-operatively
the common bile duct was found to be
normal and the gall bladder was found to
be septate. Features were consistent with
chronic cholecystitis and multiple gall
stones of varying sizes were identified. No
features of cholangitis were noted.
Post-operatively, patient was stable and
comfortable. Oral liquids were started on
day 2. Abdominal drain was removed on
day 4. He was discharged on day 6. He had
no subsequent complications and has been
asymptomatic on follow-up, 3 months later
(Figure 1-7).
Figure1: Ultrasound image showing
mass in continuity with the gall bladder

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Figure 2: CT showing dilated gallbladder
Figure 3: MRI showing dilated mass
arising from gallbladder fossa
Figure 4: MRI showing dilated mass,
possibly distended gallbladder or
choledochal cyst
Figure 5: MRCP suggestive of a large
choledochal cyst in the gallbladder fossa

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DISCUSSION
Phrygian cap, or pseudo-duplication of the
gall bladder, has an incidence of around
4% of the population5
. It is the most
common anomaly of the congenital
anomaly of the gall bladder and is a
physiological variant of anatomy, most
likely occurring as a result of an
incompletely formed congenital septum6
.
It is most commonly asymptomatic but
may rarely be associated with right upper
quadrant pain.
Originally identified by Boyden in the year
1935, this anomaly so named because of
its resemblance to the headdress worn by
people from the ancient empire of Phrygia,
located in what is now Turkey7
. He
identified it as a normal variation which is
detectable on imaging that may be
misconstrued as a pathological finding on
cholecystography and had to be
distinguished from them.
Imaging of Phrygian cap and other gall
bladder variations can be by
ultrasonography, computerized
tomography, oral cholecystography,
cholescintigraphy and magnetic resonance
cholangiopancreaticography8
.
Ultrasonography and computerised
tomography often has poor resolution,
MRCP and cholescintigraphy are the
investigations of choice – MRCP has good
resolution and cholescintigraphy can show
delayed filling of the Phrygian cap area9 10
.
Differential diagnosis includes diverticula,
embryological folds, choledochal cysts,
pericholecystic fluid collection, focal
adenomyomatosis of the gall bladder and
fibrous bands9
.
Anatomical variations of the extra-hepatic
biliary system may be detected pre-
operatively, in which case they must be
thoroughly evaluated, usually with an
MRCP or a multi-slice contrast enhanced
CT if MRCP is contra-indicated. Those
variations picked up intra-operatively
mandate common bile duct exploration to
detect associated malformations that when
missed cause inadvertent injury to the
biliary tree11
.
CONCLUSION
Phrygian cap is the most common
embryological gall bladder malformation
that may present incidentally on imaging
Figure 6: Intra-operative laparoscopic image of
gallbladder with Phrygian cap
Figure 7: Ex-vivo image of the gallbladder showing
Phrygian cap

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or during evaluation of biliary colic. When
incidental, there is no indication for a
cholecystectomy. Thorough pre-operative
evaluation with MRCP is indicated to
confirm the diagnosis and detect
associated anomalies of the biliary tree.
Intra-operatively, a common bile duct
exploration is indicated if anatomy is not
abundantly clear, especially during
laparoscopic procedures.
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