Nodular regenerative hyperplasia of the liver

Nodular regenerative hyperplasia (NRH) of the liver is a rare disease characterized by benign and diffuse hepatic micronodular transformation without fibrous septa between the nodules. It belongs to the group of intrahepatic lesions responsible for non-cirrhotic symptomatic or clinically silent portal hypertension. It should be suspected in any patient with portal hypertension, patent large hepatic vessels and no evidence of marked fibrosis or cirrhosis on histopathological liver examination. The pathogenesis of NRH is not well known, but thrombotic or inflammatory occlusion of portal venules may be a primary cause of adaptive regenerative reaction of the liver. In each patient with NRH there is a need to exclude congenital or acquired thrombophilia and myeloproliferative or autoimmune diseases. Because of the lack of specific treatment, the management of NRH is limited to elimination of agents injuring the endothelial cells, reduction of portal hypertension and anticoagulation.