Caroli disease
Updates to Article Attributes
Caroli disease is a congenital disorder comprising of multifocal cystic dilatation of segmental intrahepatic bile ducts. However, some series show that extrahepatic duct involvement may exist 2. It is also classified as a type V choledochal cyst, according to the Todani classification.
Epidemiology
Caroli disease is a rare autosomal recessive disorder which has no recognised gender predilection.
Pathogenesis
Pathologically, Caroli disease belongs to the spectrum of fibropolycystic liver disease which result from in utero malformation of the ductal plate 4. There is a high association with fibrocystic anomalies of the kidneys which share the same genetic defect (PKHD1 gene, chromosome region 6p21) 5.
The ductal plate is a layer of hepatic precursor cells that surround the portal venous branches, and is the anlage of the intrahepatic bile ducts. The manifestation of ductal plate malformation depends on the level of the biliary tree that is affected 3-5.
Thus, the simple type of Caroli disease results from the abnormal development of the large bile ducts.
In contrast, in the periportal type of Caroli disease (or Caroli syndrome), both the central intrahepatic bile ducts and the ductal plates of the smaller peripheral bile ducts are affected, with the latter leading to the development of fibrosis.
At the other end of the fibropolycystic disease spectrum are Von Meyenburg complexes, also known as biliary hamartomas which result from discrete foci of ductal plate malformation affecting the smallest bile ducts 5.
Associations
- simple Caroli disease is uncommon; it occurs more frequently with congenital hepatic fibrosis, constituting the Caroli syndrome
- medullary sponge kidney
- autosomal dominant polycystic kidney disease (ADPKD)
- autosomal recessive polycystic kidney disease (ARPKD)
Clinical presentation
Presentation is in childhood or young adulthood. The simple type presents with RUQ pain and recurrent attacks of cholangitis with fever and jaundice. The periportal fibrosis type may present with pain or signs of portal hypertension, including haematemesis from oesophageal varices1-3.
Radiographic features
The disease may be diffuse, lobar or segmental. Dilatation is most frequently saccular rather than fusiform, a feature that might help in the differential diagnosis.
Ultrasound
- may show dilated intrahepatic bile ducts (IHBD)
- intraductal bridging: echogenic septa traversing the dilated bile duct lumen
- small portal venous branches partially or completely surrounded by dilated bile ducts1,3
. - intraductal calculi
CT
- multiple hypodense rounded areas which are inseperable from the dilated intrahepatic bile ducts
- “central dot” sign: enhancing dots within the dilated intrahepatic bile ducts, representing portal radicles 1
MRI
- T1: hypointense dilatation of IHBD
- T2: hyperintense
-
T1 C+
Gd(Gd): enhancement of the central portal radicles within the dilated IHBD 1 - MRCP: demonstrates continuity with the biliary tree
Complications
- simple type
- intrahepatic stone formation
- recurrent cholangitis
- hepatic abscesses
- periportal fibrosis type
- cirrhosis and portal hypertension
- varices
- there is an increased risk of cholangiocarcinoma, which develops in 7% of patients 1
Treatment and prognosis
Prognosis is generally poor. If disease is localised, segmentectomy or lobectomy may be offered. In diffuse disease management if generally with conservative measures; liver transplantation may be an option 1.
History and etymology
It is named after Jacques Caroli (1902-1979), a French gastroenterologist, who described it in 1958 7.
Differential diagnosis
-
polycystic liver disease
- no associated biliary duct dilatation
- rarely communicate with the biliary ducts
- choledochal cyst
-
biliary hamartomas
- may be cystic
-
primary sclerosing cholangitis
- dilatation typically more fusiform and isolated;
- associated inflammatory bowel disease in 70% of caucasian patients
-
recurrent pyogenic cholangitis
- both present with sepsis and biliary dilatation
- saccular (vs. fusiform) dilatation favours Caroli disease2
- obstructive biliary dilatation
For a further CT differential, consider also focal hypodense hepatic lesions on a non contrast CT scan
-<li>small portal venous branches partially or completely surrounded by dilated bile ducts<sup>1,3</sup>. </li>- +<li>small portal venous branches partially or completely surrounded by dilated bile ducts <sup>1,3</sup>
- +</li>
-<strong>C+ Gd:</strong> enhancement of the central portal radicles within the dilated IHBD <sup>1</sup>- +<strong>T1 C+ (Gd):</strong> enhancement of the central portal radicles within the dilated IHBD <sup>1</sup>
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