GI Radiology > Liver > Masses > Focal Nodular Hyperplasia

Hepatic Masses

Focal Nodular Hyperplasia

  1. Pathogenesis:
  • Most likely seen in young women (3%).
     
  • Pathologically, is a non-capsulated nodular mass:
    • Was thought to be a vascular/hamartomatous malformation.
    • Is composed of normal hepatocytes, Kupffer cells, and bile ducts but arranged abnormally.
    • Is less than 5 cm in diameter, most commonly found peripherally in the right lobe.
    • Classic appearance: solitary, well-circumscribed mass with a central stellate scar of fibrosis even though the central scar is seen in only 20% of the cases.
  1. Radiographic findings:
  • U/S: the appearance of the lesion is variable, but low echoes in the center may be seen.
  • Noncontrast CT: the lesion has low attenuation (arrows) compared with the normal liver. The central stellate scar may also show low attenuation.
  • Contrast CT: the lesion shows homogeneous enhancement early in arterial phase (arrows) with prompt wash-out. The central stellate scar will not enhance.
  • T1-weighted MRI: the lesion is hypo-isointense to the normal liver. The central scar enhances with Gd-DTPA.
     
  • T2-weighted MRI: the lesion is isointense to slightly hyperintense to liver. The central scar is hyperintense to the liver (arrows) (in contrast to hypointense appearance of the central scar in large hemangioma).

  • Nuclear medicine: sulfur colloid scans are normal in 50%, have focal photopenic defect in 40%, or focal area of increased activity in 10%.
     
  • Angiography: classically shows a "spoke-wheel" pattern of increased vascularity (arrows).

 

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