The value of immunophenotyping hepatocellular adenomas: consecutive resections at one UK centre

To determine the utility of immunophenotyping for classification of hepatocellular adenomas resected at one Scottish centre.

This study comprised a retrospective review and immunophenotyping of consecutive resected benign hepatocellular tumours. Fifty-five patients (seven men) had 64 adenomas and 26 focal nodular hyperplasias (FNHs) resected. Map-like glutamine synthetase (GS) staining was specific for FNH. Immunophenotyping changed the morphological typing for three adenomas and resolved 16 of 18 unclassified or equivocal cases, revealing GS positivity in these (seven) and four others. Steatotic/liver fatty acid binding protein-deficient adenomas were the commonest type in women (12/29 women, 41%) but were absent from men. Where one of multiple adenomas was morphologically unclassified, there was still a shared immunophenotype. Diffuse CD34 positivity correlated with GS positivity or unclassified status (P < 0.0001). Supervised cluster analysis identified morphological discriminants for FNH and predictors of adenoma type and their insensitivity in predicting GS status. Forty per cent of men and 7% of women with adenomas had a specific adenoma risk, including danazol and portal venopathies. Inflammatory adenomas were associated with metabolic syndrome, steatosis, or alcohol (P = 0.053). Four patients showed carcinoma ex-adenoma.

The distribution of adenoma types in this population matches that in others, and immunoprofiling is required for accurate typing. Carcinoma ex-adenoma is uncommon and fits the published risk profile (large size and GS-positive).