MR Imaging of Hepatocellular Adenomas and Differential Diagnosis Dilemma
Figure 2
Inflammatory adenoma with “atoll sign.” (a) In S IX well-delineated slightly hyperintense lesion with hyperintense peripheral rim (arrow) in axial T2w image. (b-c) T1w in- and out-phased images. The mass is hypointense relative to the hepatic parenchyma with isointense rim. (d–h) In dynamic evaluation after Gd-EOB-DTPA administration the lesion shows marked central enhancement in arterial phase (e) with slight wash out in portal (f) and more evident equilibrium (g) phases. After 5′ (h) the nodule is mainly hypointense. Conversely, the peripheral component of the nodule demonstrates progressive enhancement over time. (i-j) In hepatobiliary phases after 20′, axial (i) and coronal (j), the lesion is heterogeneously hypointense in the central portion and hyperintense at the periphery (arrowheads). Final diagnosis was obtained by biopsy. Histology demonstrates ductal reaction at the periphery of the lesion (k).
