CT of liver cysts in patients with autosomal dominant polycystic kidney disease

Purpose: The purpose of this study was to illustrate the CT appearances of liver cysts in patients with autosomal dominant polycystic kidney disease (ADPKD). Material and Methods: Contrast-enhanced CT images of 24 patients with ADPKD were retrospectively evaluated for the presence, number, size and distribution of liver cysts. An attempt was made to categorize these cysts into peribiliary cysts (located adjacent to larger portal triads or in the hepatic hilum) and intrahepatic cysts (within the liver parenchyma but not in contact with larger portal triads). When it was not possible to definitely categorize the cysts into either type, the cysts were labeled as indeterminate. Results: Liver cysts were seen in 13 (54%) patients. Intrahepatic cysts were seen in 12 patients, and were mainly peripheral in location with sizes ranging from less than 10 mm to 8 cm. Peribiliary cysts were seen in all 13 patients and were usually less than 10 mm in size. These cysts were seen as discrete cysts (8 patients), a string of cysts (10 patients), or as a tubular structure paralleling the portal vessels, mimicking biliary dilatation (11 patients). Twelve patients also showed indeterminate cysts which defied definite categorization into either type; two common causes of confusion included large (more than 10 mm) discrete cysts in the hilar region and the presence of a vessel adjacent to peripheral cysts. Conclusion: Liver cysts in patients with ADPKD show a wide variety of appearances on CT. Familiarity with these findings is essential to avoid confusion with other abnormalities.