Focal nodular hyperplasia within accessory liver: imaging findings at computed tomography and magnetic resonance imaging.

Accessory liver tissue is a rare but probably underreported entity that may harbor the same spectrum of pathology as that of the parent organ. The rarity and aberrant locations of such lesions cause confusion and may lower diagnostic confidence despite otherwise classic radiographic appearances. Focal nodular hyperplasia (FNH) is the most common non-hemangiomatous benign hepatic tumor, but to our knowledge, ectopic FNH has been reported only once before in the gastroenterology literature. We present the first case of ectopic FNH in the radiology literature.