The pathogenesis of nodular regenerative hyperplasia of the liver associated with rheumatoid vasculitis.

Nodular regenerative hyperplasia (NRH) is an uncommon liver disease that typically develops in the setting of a chronic illness such as Felty's syndrome. Although the pathogenesis of NRH has not been defined, vasculitis has been postulated to play an important pathogenetic role in some cases of NRH, even though the association of NRH and vasculitis has been reported rarely. We describe two unusual cases of NRH in patients with Felty's syndrome complicated by rheumatoid vasculitis. Morphometric analysis demonstrated evidence of injury to the hepatic vasculature in the form of loss of small intrahepatic arteries and portal spaces, findings that support the hypothesis that hepatic arteritis plays a role in the development of NRH in cases associated with systemic vasculitis.