Phenotypic classification of hepatocellular adenoma: routine histology and immunohistochemistry (IHC) and molecular biology.
|Routine histology||In favor of||IHC|
|(i) Diffuse steatosis|
(ii) Lobulated contour (surgical specimen)
(iii) No criteria for IHCA
|H-HCA||Lack of LFABP → H-HCA|
(v) Sinusoidal dilatation
(vi) Pseudoportal tracts (with thick arteries)
(vii) Ductular reaction
|IHCA*||CRP/or SAA + → IHCA|
CRP/or SAA +/GS**+ → b-IHCA
| || ||GS** + (CRP−) → b-HCA|
| || ||All markers− → UHCA|
|In the absence of typical routine histological criteria for H-HCA or IHCA, the other HCA subtypes are likely *include b-IHCA (GS is mandatory to differentiate IHCA and b-IHCA).|
**Perform in addition β-catenin staining: aberrant nuclear staining confirm the diagnosis; its absence does not rule out; however, the diagnosis, particularly on needle biopsies, needs molecular biology for definite diagnosis.