Simple cysts are among the most common hepatic lesions, affecting around up to 20% of the general population.
- Definition = simple liquid filled cysts lined by benign epithelium with no malignant potential. No communication with the biliary system.
- Imaging characteristics = Demonstrates homogeneous water attenuation (<20 HU) on CT, no internal septations or mural nodularity, and no contrast enhancement. On MRI, lesions are markedly T2 hyperintense and T1 hypointense, consistent with simple fluid, with no wall enhancement or biliary communication.
- Subtypes = hepatic cysts, cystic biliary hamartomas, peribiliary cysts (in advanced cirrhosis).
- Treatment & Surveillance = If asymptomatic, there is no need for treatment or follow-up. Large or multiple cystic lesions may rarely require cyst fenestration and/or parenchymal resection.