CT and MRI features of hepatic adenoma
What is hepatic adenoma, and what are its CT and MR imaging features?
Hepatic adenoma is the second most common benign lesion of hepatocellular origin, and it is most commonly encountered in young women, especially in those who are taking oral contraceptives. It may also be associated with anabolic corticosteroid use as well as type I glycogen storage (von Gierke’s) disease. Hepatic adenoma, although a benign neoplasm, is often treated with surgical resection given the risk of hemorrhage, especially for lesions that are ≥ 3 to 4 cm and/or located in the subcapsular region of the liver. Hepatic adenomatosis is a specific rarer condition, which is defined by presence of more than 10 hepatic adenomas in the liver and which is associated with a small but increased risk of malignant transformation into HCC.
On MRI, hepatic adenoma is isointense to hyperintense relative to liver parenchyma on T1-weighted images, often contains intralesional lipid (seen by loss of signal intensity on out-of-phase T1-weighted images relative to in-phase T1-weighted images), and is isointense to slightly hyperintense relative to liver parenchyma on T2-weighted images. When subacute hemorrhage is present, foci of very high T1-weighted signal intensity will be visualized. Following contrast administration, variably heterogeneous mild to moderate arterial phase enhancement is usually present, along with isointensity or hypointensity relative to liver parenchyma on venous and delayed phases of enhancement. On hepatobiliary phase T1-weighted images, hepatic adenoma will appear hypointense relative to liver parenchyma because it does not retain hepatobiliary contrast material
On CT, hepatic adenoma may have variable attenuation relative to liver parenchyma depending on lipid content and presence of hemorrhage, and it has similar enhancement characteristics to those described on MRI
