Peribiliary cysts occur in the setting of chronic liver disease where it is a rare, benign, and often asymptomatic disorder. They consist of cystic formations around the intrahepatic biliary ducts, primarily in a hilar distribution. Unlike choledochal cysts (for example in Caroli disease), peribiliary cysts do not communicate with the biliary tree.
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Epidemiology
Peribiliary cysts are very rare and occur in the setting of severe chronic liver disease, portal hypertension 1, and in the setting of autosomal dominant polycystic kidney disease (ADPKD).
Clinical presentation
These asymptomatic cysts are diagnosed incidentally in the severe chronic liver disease cohort who have screening tests for hepatoma formation. Rare cases of mass effect have been described resulting in obstructive jaundice 2,4.
Pathology
Histologically, peribiliary cysts have benign-appearing columnar or cuboidal epithelial cell lining 3,4. They develop as dilatation of glands within the periductal tissue 3. They vary in size and have been shown to gradually increase in size and number over time 3.
Radiographic features
Ultrasound
Features include well-demarcated cysts (uniform, low echogenicity with posterior acoustic enhancement) of varying size in a hilar distribution. In particular, a positive diagnosis is made with the presence of the cystic dilatation on both sides of the portal veins, whereas dilatation of intrahepatic bile ducts usually appears on one side. Background features of chronic liver disease are associated.
CT
Low (fluid) density, well-defined intrahepatic structures around the liver hilum with no enhancement on a background of cirrhosis.
MRI
T1: hypointense compared to liver parenchyma
T2: hyperintense, that of CSF
T1 C+: no enhancement
Treatment and prognosis
Peribiliary cysts are a benign and incidental finding. Although they have been shown to grow gradually over time, they require no direct management. Patients will be serially imaged for chronic liver disease. Very rare cases may result in intrahepatic biliary dilatation due to mass effect compressing the intrahepatic ducts.
History and etymology
These were first described by Nakanuma et al. in 1984 1.
Differential diagnosis
Imaging differential considerations include:
von Meyenburg complexes: although in this setting biliary hamartomas are more diffuse throughout the liver rather than hilar in distribution and would be more space out
Caroli disease: a congenital disorder involving multifocal intrahepatic choledochal cysts of the segmental intrahepatic bile ducts