Focal Nodular Hyperplasia
FNH is generally considered to be a non-neoplastic process consisting of a localized overgrowth of hepatocytes. Most lesions are well-circumscribed, unencapsulated, and nodular with a central fibrous zone and light tan parenchyma. Grossly, it may resemble macronodular cirrhosis. FNH is often subcapsular and may be pedunculated. It usually occurs in adults, although cases have been reported in children. It is more common in females and has been linked to oral contraceptive use. Other risk factors include chronic alcohol consumption, Budd-Chiari Syndrome, and orthotopic liver transplantation. Unlike liver cell adenoma, hemorrhage and necrosis are rare. Most cases are asymptomatic. Image courtesy of Dr. Jean-Christophe Fournet, Paris, France; humpath.com; Used with permission.