Focal Liver Lesions in the Non-Cirrhotic Liver

1. Hepatic Cyst Hepatic cysts are common benign lesions that occur in 2%-10% of the population. They may be solitary or multiple and range in size from a few millimeters to several centimeters. Hepatic cysts are usually discovered incidentally and have no malignant potential. On MR imaging, they are well-defined, round or oval lesions with thin, almost imperceptible walls. Simple cysts are very hypointense on T1-weighted sequences and very hyperintense on T2-weighted sequences, corresponding to the signal characteristics of fluid. Additionally, simple cysts demonstrate no internal architecture and no gadolinium contrast enhancement. Biliary hamartoma may be indistinguishable from simple hepatic cysts but are also benign entities. Indeterminate subcentimeter hypodensities seen on CT in patients with known primary carcinomas can usually be definitively diagnosed on MRI.