Magnetic resonance imaging findings of atypical focal nodular hyperplasia of the liver.

Atypical focal nodular hyperplasia (FNH) of the liver is a diagnostic challenge as a variety of atypical imaging findings can occur in this entity. There is no potential for malignant transformation, making noninvasive diagnosis welcome in order to avoid invasive steps such as biopsy or surgery. The present pictorial review focuses on the atypical presentation of FNH and comments on different types of contrast media available for magnetic resonance imaging of the liver.