[1676] Hepatocellular Adenomas in a Large Community Population 2000-2010: Reclassification Per Current WHO Classification and Long-Term Follow-Up

Gillian Genrich, Nafis Shafizadeh, Linda Ferrell, Sanjay Kakar. University of California San Francisco, San Francisco, CA; Southern California Permanente Medical Group, Woodland Hills, CA

Background: Data for WHO classification of hepatocellular adenoma (HA) is largely based on cases from tertiary care centers. This study examines distribution of HA subtypes in a community setting and determines the impact of immunohistochemistry (IHC) on reclassification, diagnosis, and management.
Design: All cases diagnosed as HA in a large community hospital from 2000-2010 were reviewed (n= 49) to confirm the diagnosis. Where tissue was available (n=35), IHC was performed for evaluation of HA: liver fatty acid binding protein (L-FABP), serum amyloid A (SAA), C-reactive protein(CRP), beta-catenin (bC), glutamine synthetase (GS), heat shock protein 70 (HSP70) and glypican-3 (GPC).
Results: There were 35 cases available for IHC evaluation. The reclassification of HAs was based on histopathologic and immunophenotypic features.

Table 1: Reclassification of HAs over a 10-year period (n=35)
HNF1alpha inactivated9/35 (26%)
Inflammatory7/35(20%)
B-catenin activated/atypical6/35 (17%)
Unclassified9/35 (26%)
Very Well-differentiated HCC1/35 (3%)
Focal Nodular Hyperplasia3/35 (9%)


There was histopathologic and immunophenotypic agreement in 26 cases (26/35). However, in 9 cases the diagnosis or HA classification was changed upon review of IHC stains. The immunophenotype by HA subtype is shown.

Table 2: Immunophenotype of cases of hepatocellular adenoma (n=31)
 LFABPSAACRPbCGSHSP70GPC
HNF inactivatedNegativeNegativeNegativeMembraneVariableNegativeNegative
Beta-catenin/atypicalPositiveNegativeNegative+/- Membrane; NuclearDiffuseNegativeVariable
InflammatoryPositivePositivePositiveMembraneVariableNegativeNegative
UnclassifiedPositiveNegativeNegativeMembraneVariableNegativeVariable


Clinical follow-up was available for 33 cases (33/35), including the HCC case; no case developed metastasis. The majority of HAs (18/30) were treated with resection without recurrence; in 6 cases (6/33) that were untreated and followed, the HAs remained stable.
Conclusions: IHC led to HA reclassification in 26% of cases. Distribution of HA cases (n=31) at a community hospital differs from prior studies (Bioulac-Sage), with fewer HNF-1 inactivated (29% vs 35-40%) and inflammatory subtypes (23% vs. >50%); and greater beta-catenin activated/atypical (19% vs 10-15%) and unclassified subtypes (29% vs. 5-10%). The smaller proportion of inflammatory subtypes may reflect earlier classification of these lesions as telangiectatic FNH.
Category: Liver

Monday, March 4, 2013 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 258, Monday Morning

 

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