Caroli disease is a congenital disorder comprising of multifocal cystic dilatation of segmental intrahepatic bile ducts. It is also classified as a type V choledochal cyst, according to the Todani classification.
Caroli disease is a rare autosomal recessive disorder which has no recognised gender predilection.
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 ducts5.
- 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)
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
The disease may be diffuse, lobar or segmental.
- 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
- 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
- T1 : hypointense dilatation of IHBD
- T2 : hyperintense
- C+ Gd : enhancement of the central portal radicles within the dilated IHBD1
- MRCP : demonstrates continuity with the biliary tree
- simple type :
- intrahepatic stone formation
- recurrent cholangitis
- hepatic abscesses
- periportal fibrosis type :
- there is an increased risk of cholangiocarcinoma
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 option1.
polycystic liver disease
- no associated biliary duct dilatation
- rarely communicate with the biliary ducts
- choledochal cyst
- may be cystic
primary sclerosing cholangitis
- dilatation typically more fusiform and isolated;
- associated inflammatory bowel disease
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
- 1. Federle MP, Jeffrey RB, Woodward PJ et-al. Diagnostic Imaging: Abdomen, Published by Amirsys®. Lippincott Williams & Wilkins. (2009) ISBN:1931884714. Read it at Google Books - Find it at Amazon
- 2. Levy AD, Rohrmann CA, Murakata LA et-al. Caroli's disease: radiologic spectrum with pathologic correlation. AJR Am J Roentgenol. 2002;179 (4): 1053-7. AJR Am J Roentgenol (full text) - Pubmed citation
- 3. Fulcher AS, Turner MA, Sanyal AJ. Case 38: Caroli disease and renal tubular ectasia. Radiology. 2001;220 (3): 720-3. doi:10.1148/radiol.2203000825 - Pubmed citation
- 4. Desmet VJ. Ludwig symposium on biliary disorders--part I. Pathogenesis of ductal plate abnormalities. Mayo Clin. Proc. 1998;73 (1): 80-9. doi:10.4065/73.1.80 - Pubmed citation
- 5. Rodés J, Benhamou J, Rizzetto M. Textbook of hepatology, from basic science to clinical practice. Wiley-Blackwell. (2007) ISBN:1405127414. Read it at Google Books - Find it at Amazon
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