between these lesions and vascular shunting is further supported by the presence of focal nodular hyperplasia lesions in patients with hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu disease)14 as well as hemihypertrophy and vascular malformations (Klippel-Trénaunay-Weber syndrome).15
Figure 27.3 Focal nodular hyperplasia. The central stellate scar with radiating “spoke in wheel” fibrous bands is a highly characteristic feature, although may be absent in smaller lesions.
Figure 27.4 Focal nodular hyperplasia. The scar-like tissue within these lesions contain abnormal large arteries, some of which may have medial hypertrophy, such as seen in this eccentric artery.
Figure 27.5 Focal nodular hyperplasia. Native bile ducts are replaced by prominent bile ductular proliferation traveling along the edge of the fibrous septae or at the periphery of the lesion.
Mallory hyaline accumulation in areas adjacent to the fibrous bands. Hepatocytes within the focal nodular hyperplasia can also show steatosis, and lymphocytic inflammation may be found in the fibrous bands.
ducts within true portal tracts should steer one away from a diagnosis of focal nodular hyperplasia. As noted before, glutamine synthetase immunostains will show a map-like staining pattern in focal nodular hyperplasia, whereas the normal liver parenchyma will show reactivity in only a small rim of hepatocytes surrounding the central vein.
patients have 10 or more lesions—a condition called hepatic adenomatosis.34
Key histologic features and staining patterns of benign hepatocellular neoplasms with comparison to hepatocellular carcinoma