peribiliary cysts are cystic dilatations of the peribiliary glands of the liver hilum and portal tracts , which lack communication with the lumen of the biliary tree [ 1 , 2 ] .
peribiliary cysts are often under diagnosed , however , as they are usually asymptomatic and the reported prevalence based on imaging diagnosis is only 9% in among patients with cirrhosis .
they are therefore often discovered incidentally , though rarely can lead to symptoms such as obstructive jaundice , and intrahepatic ductal dilatation on cholangiography , which may be misinterpreted as intrahepatic or hilar cholangiocarcinoma ( cca ) [ 1 , 6 ] .
misdiagnosis of peribiliary cysts as cca in patients with decompensated cirrhosis may lead delay or denial in listing an otherwise suitable candidate for orthotopic liver transplantation ( olt ) .
we present a case of a patient awaiting olt , with a new finding of intrahepatic biliary ductal dilatation initially thought to be secondary to cca , but ultimately diagnosed as multiple peribiliary cysts .
his decompensations included hepatic encephalopathy and ascites for which he underwent transjugular intrahepatic portosystemic shunt procedure . in may 2015 ,
the patient was hospitalized for acute on chronic liver failure , with a rise in his model for end - stage liver disease ( meld ) score from 19 to 35 . on physical examination , he had jaundice , abdominal distension and bilateral peripheral edema .
initial blood tests revealed an alkaline phosphatase at 599 u / l ( reference  < 125 u / l ) and total bilirubin at 13.6 ( direct bilirubin 11.6 ) .
u / l ( normal 045 u / l ) and aspartate transaminase ( ast ) 358 u / l ( normal 035 u / l ) .
carbohydrate antigen 19 - 9 ( ca 19 - 9 ) was normal at 4 .
baseline hepatic function tests from 2 weeks prior revealed an alkaline phosphatase of 93 , total bilirubin of 6.4 , direct bilirubin of 2.7 , alt of 23 , ast of 85 and inr of 2 .
magnetic resonance imaging ( mri ) of the abdomen revealed increased t2 signal intensity within the bile ducts and significant dilation predominantly of the left biliary ductal system , with a lesser dilation of the right - sided bile ducts ( fig .
1 ) . this was a new finding as compared to imaging from 6 months prior to hospitalization .
the cholestatic pattern of liver enzyme abnormality and new biliary ductal dilatation in the absence of choledocholithiasis or a pancreatic head mass was concerning for cca . 

figure 1:mri abdomen demonstrating increased t2 signal intensities along the left bile ducts and to lesser extent the right bile ducts .
mri abdomen demonstrating increased t2 signal intensities along the left bile ducts and to lesser extent the right bile ducts .
endoscopic ultrasound ( eus ) demonstrated a complex cystic mass at the hilum measuring 29.8    28.6 mm .
endoscopic retrograde cholangiopancreatography ( ercp ) revealed an irregular common hepatic duct with a stricture at the hilum and a stricture of the left intrahepatic duct , with proximal intrahepatic ductal dilation ( fig .
there was suspicion that the liver hilum was biopsied rather than the targeted cystic mass , thus cca could not be ruled out .
the decision was made to perform a biopsy of the cystic mass at the time of olt and to abort transplantation if there was evidence of malignancy . 

figure 2:ercp demonstrating mild - to - moderate intrahepatic ductal dilatation with multifocal biliary strictures .
ercp demonstrating mild - to - moderate intrahepatic ductal dilatation with multifocal biliary strictures . in june 2015
, the patient underwent olt . both manual inspection and frozen section examinations of four lymph nodes from the portal structures and the distal margin of the common bile duct ruled out malignancy .
examination of the explant revealed a 4.0    3.5    2.0 cm cystic area at the hilum , 0.2 cm from the bile duct margin .
the cysts appeared to run adjacent to the right and left hepatic ducts and caused focal narrowing of the bile duct lumen with proximal biliary ductal dilatation .
figure 3:the liver was grossly cirrhotic with an ill - defined lesion consisting of multiple variably sized cystic spaces in the hilar area that did not communicate with the bile ducts . 

sections of the cystic spaces showed variably sized cystic structures predominately lined by simple cuboidal to columnar biliary - type epithelium .
the liver was grossly cirrhotic with an ill - defined lesion consisting of multiple variably sized cystic spaces in the hilar area that did not communicate with the bile ducts .
sections of the cystic spaces showed variably sized cystic structures predominately lined by simple cuboidal to columnar biliary - type epithelium .
peribiliary cysts may present a diagnostic challenge in the patient with end - stage liver disease , due to the possibility of being mistaken for cholangiocarcinoma [ 3 , 7 ] .
such a misdiagnosis can result in delay in listing for olt or even inappropriate exclusion from transplantation , in otherwise acceptable candidates
. therefore , awareness of this condition is of critical importance to the transplant physician and surgeon .
the ideal imaging modalities to identify peribiliary cysts include magnetic resonance cholangiography / pancreatography ( mrcp ) and drip infusion cholangiographic computed tomography ( dic - ct ) . while mri can demonstrate the presence of cysts , a diagnostic feature of peribiliary cysts is their lack of communication with the biliary tree .
this can be confirmed using mri with 2d and 3d mrcp sequences , where the cysts appear as a string of bead - like lesions along the hepatic hilum and/or bile ducts .
dic - ct is another option to diagnose peribiliary cysts , though prior reports where peribiliary cysts were diagnosed by dic - ct were in patients without liver disease .
dic - ct may have a limited role in identifying peribiliary cysts in patients with decompensated cirrhosis since it requires normal hepatic function to clearly depict the bile ducts .
hepatic dysfunction and hyperbilirubinemia are known to result in insufficient delineation of the bile ducts when using dic - ct .
therefore , mrcp may be a better modality for identifying peribiliary cysts in those with end - stage liver disease . in our patient , the diagnosis of peribiliary cysts was not made until explant examination despite performance of mri without mrcp , eus and ercp .
although the patient did not undergo mrcp , the combination of mri and ercp could have led to a diagnosis of peribiliary cysts prior to examination of the explant .
our case , therefore , demonstrates the importance to the transplant community of being cognizant of this condition , and further suggests that a diagnosis of peribiliary cysts should be considered in patients with cirrhosis who present with intrahepatic biliary dilatations and obstructive jaundice . in conclusion , we present a case which demonstrates that peribiliary cysts may present with imaging findings concerning for cca .
imaging with mrcp and dic - ct can make a definitive diagnosis , though the degree of hepatic dysfunction may limit the usefulness of dic - ct .
the diagnosis of peribiliary cystic disease should be considered in patients with end - stage liver disease who present with cholestasis and biliary ductal dilatation , along with negative biopsy of the biliary ductal system for malignancy .
 peribiliary cysts are cystic dilatations of peribiliary glands in the liver . 
 they are present in ~50% of cirrhotic patients , but are underrecognized because they are usually asymptomatic and rarely present as obstructive jaundice . a 63-year - old male with hepatitis c cirrhosis , awaiting liver transplantation , had a new finding of intrahepatic dilatation on magnetic resonance imaging . 
 this was initially concerning for cholangiocarcinoma , but was ultimately diagnosed as peribiliary cysts . 
 peribiliary cysts can imitate cholangiocarcinoma on imaging . 
 therefore , awareness of this condition is essential because misdiagnosis may lead to inappropriate delay or denial for liver transplantation . 
 the ideal imaging modalities to identify peribiliary cysts are magnetic resonance cholangiography and drip infusion cholangiographic computed tomography , though hepatic dysfunction may limit the usefulness of the latter . 
 peribiliary cysts should be considered in cirrhotic patients with cholestasis , biliary dilatations and negative biopsy of the biliary system for malignancy . 