Presentation
The patient is a known case of chronic liver disease and multiple episodes of variceal hemorrhage, who is a liver transplant candidate and underwent a CT scan for pre-transplant evaluation.
Patient Data
Evidence of portal hypertension: splenomegaly as well as coronary and para-esophageal collaterals. The liver volume redistribution and subtle liver surface irregularity are in favor of cirrhotic changes. Multiple focal cystic dilations of intrahepatic bile ducts are visible, more prominent in the right liver lobe, some of them show the central dot sign in favor of Caroli disease. Several small renal stones and a calcified gallstone are other findings.
The red arrows point to the central dot sign, which represents an intrahepatic portal vein branch passes through an abnormally dilated bile duct.
Case Discussion
Although non-specific, the central dot sign could be helpful to differentiate Caroli disease from other causes of focal intrahepatic biliary dilation. This sign could be seen in peribiliary cysts, periportal lymphedema, or severe obstructive biliary dilation too. However, it is absent in PSC or recurrent pyogenic cholangitis.