Transient arterial enhancement in a hepatic peritumoral fat-spared area.

Early-enhancing areas that are perfusion abnormalities rather than tumor deposit are sometimes encountered on arterial dominant-phase images in multisection dynamic magnetic resonance imaging. Focal sparing in diffusely fatty liver is also a well recognized entity. However, both conditions occasionally create problems in the diagnosis of hepatic mass lesions. Familiarity with these abnormalities on ultrasonography and multisection dynamic magnetic resonance images is important to prevent misinterpretation of these pseudolesions as real masses. In addition, focal sparing can be the only clue for a space occupying lesion in the liver. We present here the ultrasonography and magnetic resonance imaging findings of a case with liver metastasis from pancreas cancer which caused a wedge-shaped fat-spared enhancing area on dynamic magnetic resonance imaging.