Table 2.

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
(iv) Inflammation (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.