Use of alpha-1-antitrypsin staining in the diagnosis of nodular regenerative hyperplasia of the liver

Abstract

Nodular regenerative hyperplasia (NRH) is a disorder characterized by regenerative nodules scattered diffusely throughout the liver without associated fibrosis. It is most often recognized at autopsy when the entire liver is available for inspection. The diagnosis of NRH by needle biopsy is much more subtle. Since alpha-1-antitrypsin (AAT) expression by hepatocytes in a variety of liver diseases has suggested that it may represent a marker for regenerative or damaged hepatocytes, we elected to study the expression of AAT by immunohistochemical staining of paraffin-embedded tissue of biopsy material as a possible marker of this diagnosis. Seventeen biopsies of the liver showing histologic features consistent with NRH were selected and compared with 20 biopsies of the liver without features of NRH. Eight of the NRH cases showed periportal granular AAT staining as opposed to only one of the non-NRH biopsies (P less than .01; Fisher exact test). These results indicate that AAT expression is increased in the regenerating compartment (as opposed to the presumably damaged atrophic portion) of the liver in NRH and suggest that AAT staining may be useful in confirming the biopsy diagnosis of NRH.