autosomal dominant polycystic kidney disease ( adpkd ) is an inherited disorder mainly associated with renal cyst formation and renal function deterioration . as originally reported , the entity is characterized by : 1 ) segmental cystic dilatation of the intrahepatic bile ducts ; 2 ) high incidence of intrahepatic cholelithiasis , cholangitis , and hepatic abscesses ; 3 ) absence of cirrhosis and portal hypertension ; and 4 ) association with renal tubular ectasia or medullary sponge kidney and , in some instances , pancreatic cysts . the combination of caroli 's disease and congenital hepatic fibrosis is commonly known as caroli 's syndrome . caroli 's disease or syndrome is often associated with autosomal recessive polycystic kidney disease ( arpkd ) , but it is a rare complication of adpkd . only four case reports describing adpkd associated with caroli 's disease or syndrome have previously been published ( 3 - 6 ) . renal and hepatic cyst infections are the major causes of a fever in adpkd patients ( 7 ) . infection of the hepatobiliary tract has also been reported to occur in adpkd patients with hepatobiliary morphologic abnormalities . we herein report a rare case of adpkd with caroli 's disease and recurrent hepatobiliary infection . the study of this case was approved by the institutional review board of toranomon hospital . a 76-year - old woman was admitted to our hospital for the evaluation of an intractable fever with chills in august 2012 . transcutaneous renal arterial embolization was performed to reduce abdominal distension related to enlarged kidneys in 2007 ( 8) . the patient had presented with a high fever and bacteremia once or twice per year since 2009 , and renal or hepatic cyst infection was considered to be causative on each occasion . on this admission , the patient was 150.3 cm tall and weighed 54.7 kg , with a blood pressure of 138/61 mmhg and a temperature of 38.3. a physical examination revealed no jaundice or abdominal tenderness . regarding enzymes related to hepatobiliary tract diseases , only alkaline phosphatase ( alp ) was increased slightly . a blood culture was positive for extended - spectrum -lactamase - producing escherichia coli ( esbl - e . coli ) . magnetic resonance imaging ( mri ) indicated multiple large renal cysts consistent with adpkd and multiple hepatic cysts located mainly in peribiliary regions ( fig . there were no signs of cyst infections on mri , such as an increased intensity on diffusion - weighted imaging , niveau , wall thickening , or gas in the cysts , which we previously reported to be typical findings of infected cysts ( 9 ) . mri revealed a common bile duct stone and cystic dilatation of the intrahepatic bile ducts in the left lobe ( fig . contrast - enhanced abdominal computed tomography ( ct ) showed the central dot sign representing the fibrovascular bundle within the dilated cystic intrahepatic ducts ( fig . 2 ) , which was considered to be characteristic feature of caroli 's disease ( 10 ) . endoscopic retrograde cholangiography ( erc ) also demonstrated cystic dilated biliary ducts with stones ( fig . one black stone suggesting bilirubin origin was removed under erc , but unremovable stones existed . ( a ) magnetic resonance imaging ( mri ) indicated multiple large renal cysts consistent with adpkd and multiple hepatic cysts located mainly in peribiliary regions . ( b ) mri revealed cystic dilatation of the intrahepatic bile ducts in the left lobe and peribiliary cysts . contrast - enhanced abdominal ct showed the central dot sign ( circle ) , representing the fibrovascular bundle ( arrow ) within the dilated cystic intrahepatic ducts , which is considered to be a characteristic feature of caroli 's disease . sepsis was controlled with intravenous meropenem , however , the fever recurred when the treatment was changed to oral antibiotics , as shown in fig . the patient exhibited febrile episodes five times within a year due to cholangitis , liver abscess , or hepatic cyst infection . since september 2013 , the patient has received intravenous meropenem treatment at every hemodialysis session and cholangitis has been controlled since that time . the presence of caroli 's disease or syndrome has previously been described in conjunction with arpkd , which usually has a childhood onset . the association of caroli 's disease with adpkd is rare ( 3 - 6 ) . both caroli 's disease and hepatic cysts in adpkd are regarded as fibrocystic liver diseases , which comprise a group of congenital disorders resulting from ductal plate malformation , i.e. , abnormal embryogenesis of the biliary ductal system ( 11 ) . a ductal plate is defined as a cylindrical layer of cells that surrounds a branch of the portal vein and develops during the first week of gestation ( 12 ) . the clinicopathological abnormality of fibrocystic liver disease is dependent on the level of the biliary tree affected during embryogenesis . the disease entities can exist as individual conditions or in combination ( 11,13 ) . a mutation in pkd1 encoding polycystin-1 or pkd2 encoding polycystin-2 gives rise to adpkd . these proteins localize to primary cilia of renal tubule cells and cholangiocytes ( 15 ) . although the hepatic phenotype of caroli 's disease generally appears in arpkd , the phenotype of caroli 's disease was observed in adpkd patient in the present case . observed intrahepatic bile duct abnormalities in 25 of 90 adpkd patients ( 27.8% ) with magnetic resonance cholangiography , which were correlated with hepatobiliary infection ( 16 ) . ishikawa et al . reported that common bile duct dilatation occurred more frequently in adpkd patients than in non - adpkd patients ( 17 ) . terada et al . examined specimens from autopsied livers and biliary tracts of three patients with adpkd using intrahepatic cholangiography and found nonobstructive dilatation of the intrahepatic bile ducts in all cases ( 18 ) . reported the 17-year history of an adpkd patient with a recurrent fever of unknown origin that was later attributed to caroli 's disease with multiple episodes of cholangitis ( 4 ) . these phenotypic variants might be due to differences in the type or locus of the mutation of responsive genes , epigenetic mechanisms , and/or environmental factors ( 19 ) . our case presented with a recurrent fever and septicemia for several years . at first , renal or hepatic cyst infections were thought to be the cause of the fevers , because they are the most common causes of a fever in adpkd ( 7 ) . however , diagnostic imaging findings revealed the characteristic hepatobiliary abnormalities of caroli 's disease that lead to recurrent cholangitis with hepatobiliary stones . the patient did not present with abdominal pain , and her laboratory findings did not indicate liver function abnormality , except for a slight elevation of alp . the treatment of caroli 's disease is largely supportive and should be individualized ( 20 ) . cholangitis and sepsis should be treated with appropriate antibiotics and biliary stone extraction whenever feasible . partial hepatectomy may be curative in rare patients in whom the disease is confined to a single lobe of the liver ( 21 ) . patients who have recurrent bouts of biliary infection , particularly those who also have complications related to portal hypertension , may require liver transplantation ( 22 ) . in the present case , it was difficult to choose surgical intervention because of the patient 's old age and general condition . the prognosis is variable depending upon the severity of disease and the presence of coexisting renal dysfunction . recurrent infections and other complications related to biliary lithiasis can be associated with significant morbidity . we herein experienced the rare case of an adpkd patient with caroli 's disease . in conclusion , when we encounter intractable bacterial infection in adpkd patients , we have to consider cholangitis related to abnormalities of hepatobiliary systems , such as caroli 's disease , as well as cyst infection .
we herein present a rare case of an autosomal dominant polycystic kidney disease ( adpkd ) patient with caroli 's disease , a congenital embryonic biliary tree ductal plate abnormality often associated with autosomal recessive polycystic kidney disease . 
 a 76-year - old woman with adpkd on hemodialysis was admitted to our hospital with recurrent cholangitis and hepatobiliary stones . 
 caroli 's disease was diagnosed according to typical imaging findings of cystic intrahepatic bile duct dilatation and the central dot sign . 
 hepatobiliary system abnormalities such as caroli 's disease should be considered in febrile adpkd patients , even in the absence of typical clinical signs or symptoms .