Hepatocellular adenoma: An unsolved diagnostic enigma

Figure 1 Diagnostic challenges in hepatocyte nuclear factor 1A mutated hepatocellular adenoma. A: In a 51-year-old woman, the axial T1 in-phase image shows an isointense lesion in liver segment V; B: With signal dropout in the T1 out-of-phase image; C: Slightly hyperintense in the T2-weighted; D: In diffusion-weighted; E: In the arterial phase images; F: Washout of the contrast media in the portal-venous phase; G: In the delayed phase images; H: Hypointense in the hepatobiliary phase image. According to the current guidelines, this lesion is suggestive for a hepatocellular adenoma inactivated for HNF-1α. However, according to the newer proposed classification of hepatocellular adenoma, it is not possible to exclude an inflammatory hepatocellular adenoma containing fat and, as consequence, even a mixed form of β-catenin activated-inflammatory hepatocellular adenoma, on imaging.

Figure 2 Diagnostic challenges in the imaging classification of hepatocellular adenoma. A: In a 47-year-old woman the axial T1 in-phase; B: Out-of-phase images show an isointense lesion in liver segment V; C: Hyperintense in the T2-weighted; D: In the diffusion-weighted; E: In the arterial phase images; F: Without washout of the contrast media in the portal-venous phase; G: In the delayed phase images; H: Hypointense in the hepatobiliary phase image. According to the current guidelines, this lesion is suggestive for an inflammatory hepatocellular adenoma. However, it is not possible to exclude a mixed form of β-catenin activated-inflammatory hepatocellular adenoma or even a hepatocellular adenoma inactivated for HNF-1α without fatty component.