Use of orcein as an adjunct stain in the evaluation of advanced fibrosis.

AIMS: Advanced liver fibrosis can regress following the elimination of causative injuries. Trichrome (TC) stain has traditionally been used to evaluate the degree of fibrosis in liver, although it is rarely helpful in assessing quality of fibrosis (i.e. progression and regression). Orcein (OR) stain highlights established elastic fibres, but its use in examining fibrosis is not well recognised. This study assessed the potential utility of comparing OR and TC staining patterns to evaluate the quality of fibrosis in various settings of advanced fibrosis.

METHODS AND RESULTS: The haematoxylin and eosin and TC stains of 65 liver resection/explant specimens with advanced fibrosis caused by different elements were reviewed. Twenty-two cases were scored as progressive (P), 16 as indeterminate (I) and 27 as regressive (R) using TC stain based on the Beijing criteria. The OR stains confirmed 18 of 22 P cases. The remaining P cases showed either stable fibrosis or mixed P and R. Of the 27 R cases, 26 were supported by OR stain, with many showing thin perforated septa typically seen in adequately treated viral hepatitis cases. The 16 I cases showed a variety of OR staining patterns, which allowed for further subclassification than using TC stain alone. Viral hepatitis cases were enriched for regressive features (17 of 27).

CONCLUSIONS: Our data demonstrated the utility of OR as an adjunctive stain to evaluate the changes in fibrosis in cases of cirrhosis.