New imaging techniques, such as triple phase spiral CT and fast MR imaging, have markedly increased the detection of focal nodular hyperplasia, the second most common benign hepatic tumor. Although atypical imaging features are the exception rather than the rule, it is sometimes difficult to differentiate focal nodular hyperplasia lacking characteristic findings from other primary and secondary hepatic lesions [1]. The purpose of this essay, in which all illustrated atypical cases are pathologically proven, is to present the spectrum of common and uncommon patterns encountered in CT and MR imaging of focal nodular hyperplasia, in correlation with the pathologic features. Atypically, focal nodular hyperplasia may present as a large lesion, sometimes multiple in localization, and may show internal necrosis, hemorrhagic foci, and fatty infiltration. Other rare imaging features include nonvisualization of the central scar, and pseudocapsular enhancement on delayed imaging. Because familiarity with these varied CT and MR imaging features is essential for an accurate diagnosis, it is important for radiologists not only to be aware of these uncommon appearances of focal nodular hyperplasia but also to understand the radiologic-pathologic correlation.