Case 196: Focal Nodular Hyperplasia (FNH)
28 year old woman with left upper quadrant pain with incidental finding on abdominal US.
MR: Central, typical
Unenhanced T1w fat-saturated sequence shows a hypointense FNH within segment 4a with a more hypointense central scar. On T2w fat-saturated sequences the FNH is iso- to slightly hyperintense to liver parenchyma with a central hyperintense scar and another focus of hyperintensity laterally representing additional fibrotic scar. There is no restricted diffusion.
Post contrast T1w fat-saturated sequence in arterial phase shows homogeneous hyperenhancement of the FNH that becomes isointense to liver on the portal venous phase. Hepatobiliary phase 20 minutes after Gd-EOB-DTPA administration demonstrates increased signal in the periphery of the FNH that is due the presence of hepatocytes that take up hepatospecific contrast agents. The lack of hepatocytes within the fibrotic scars results in the low signal on hepatobiliary phase.
Incidentally, a syrinx of the thoracic spinal cord is identified on the T2w sequences.