The orange-cross section appearance in focal nodular hyperplasia

Excerpt

Focal nodular hyperplasia (FNH) is the second most common benign hepatic neoplasm [1‐3]. It is believed to represent a hyperplastic regenerative response to vascular injury or congenital vascular malformations. FNH is a focal hepatic tumor formed by the proliferation of non-neoplastic hepatocytes that are abnormally arranged in a nodular aspect. The use of gadoxetic acid as a hepatocellular MR contrast agent facilitates the differentiation between FNH and other liver lesions [4] allowing dynamic images of the arterial and portal phase, followed by the hepatobiliary phase. The fibrous component, typically a stellate central scar with arterial vessels within [2], and the absence of portal vessels are responsible for the hypervascularity and intense arterial enhancement of the tumor in the dynamic images, except for its central scar, which presents delayed enhancement due to the fibrous component [3]. The FNH bile ducts (pre-existent or abnormal bile ducts) are responsible for the excretion of gadoxetic acid in the hepatobiliary phase MRI images with various enhancement patterns, unlike other focal hepatic lesions, such as metastases, adenoma, or hepatocellular carcinoma, which usually do not show enhancement during the hepatobiliary phase [2, 4]. …