Figure 4. a–c.

Axial T2-weighted (a), arterial (b), and venous (c) T1-weighted MR images of the liver with a typical presentation of an inflammatory HCA. The lesion presents with an “atoll sign” (a), which appears as a T2-weighted hyperintense rim (peripheral island with central sea) with or without central hyperintense islands as can be found inside an atoll. The lesion is hypervascular in the arterial phase (b), with late enhancement of the peripheral rim and central islands (c). Upon histology, these lesions demonstrate positive immunostaining of inflammatory proteins including C-reactive protein and serum amyloid A. The T2-weighted hyperintense rim is thought to be caused by local peliosis.