INTRODUCTION: It has been suggested that the elastic network plays an important role in the tissue response to mechanical stress. The components of the elastic network have been poorly studied in
liver diseases. Therefore, in this work, the expression and distribution of
fibrillin-1 and
elastin were studied in hepatic
focal nodular hyperplasia and compared with surrounding liver and
hepatocellular adenoma. METHODS: Immunohistochemical studies for
fibrillin-1 and
elastin were performed on unfixed cryostat sections of
focal nodular hyperplasia (22 cases),
hepatocellular adenoma (15 cases) and surrounding liver (34 cases). RESULTS: Surrounding normal liver showed only a continuous, thin and regular immunostaining of
fibrillin-1 in the space of Disse, whereas
elastin was nearly absent. In
focal nodular hyperplasia,
fibrillin-1 was more strongly expressed in the perisinusoidal space, compared with surrounding liver; in contrast, in
adenomas fibrillin-1 immunostaining was irregular and very low in perisinusoidal space, more intense in peliotic areas. CONCLUSIONS: In
focal nodular hyperplasia, the increased microfibrillar network containing
fibrillin-1 in the space of Disse could reflect an adaptation of the sinusoidal wall to an increased arterial blood flow in sinusoids. In
hepatocellular adenoma, the different patterns of
fibrillin-1 could be related to the heterogeneity of the arterial vascularization and to the frequent necrotico-hemorrhagic changes. This study comparing the elastic network in two types of lesions with vascularization abnormalities and in the surrounding liver provides interesting new data for understanding the structural role of
fibrillin-1 in the space of Disse.