[1573] Immunohistochemical Classification of Hepatic Adenomas and Atypical Hepatocellular Neoplasms: Correlation with Clinicopathologic Characteristics and Chromosomal Abnormalities

K Evason, J Grenert, L Ferrell, S Kakar. UCSF, San Francisco, CA

Background: The distinction of hepatic adenomas(HA)from hepatocellular carcinoma(HCC)is difficult in males,elderly women,or when focal atypical features are present.These tumors can show chromosomal abnormalities(Chr Abn)typical of HCC and can recur or metastasize.Recently,HAs have been classified based on inflammatory features and β-catenin(βC)pathway abnormalities.The latter may have higher risk for progression to HCC.We examine the relationship of SAA expression and βC abnormalities with clinicopathologic features and Chr Abn.
Design: Immunohistochemistry for βC,glutamine synthetase(GS)and serum amyloid associated protein(SAA)was done in 23 HA,36 AHN and 18 well-differentiated HCC.AHN was used for HA-like tumors in men,women >50 or <15 years and/or with focal atypia(small cell change,pseudoglands,thick plates).Tumors with nuclear βC and/or diffuse GS were regarded as βC abnormal.Chromosomal gains/losses had previously been determined in 39 cases using CGH or FISH.
Results: βC and Chr Abn in AHNs were more common than HA,but were similar to HCC(table1).HAs and AHNs with abnormal βC were associated with atypical morphology(table2).Follow-up data was limited but adverse outcome was observed in 3 tumors with abnormal βC(2 recurrences,1 metastasis);in addition,transition to areas of HCC was observed in 2 cases.Chr Abn were more often seen in tumors with abnormal βC(89%vs12%,p<0.001).

InflammationTelangiectasiaβC abnormalSAA +Chr Abn
p value0.170.190.003,0.210.58,0.030.007,0.3
Figures reflect percentages;p values are AHN vs HA,AHN vsHCC

Atypical age/sexAtypical morphologyInflammationTelangiectasiaChr Abn
βcatenin abn vs normal43 vs 3071 vs 2035 vs 4435 vs 3889 vs 12
p value0.17<0.0010.20.23<0.001
SAA positive vs negative43 vs 2233 vs 4248 vs 2645 vs 2150 vs 38
p value0.120.370.10.080.47

Conclusions: Most adenoma-like neoplasms with βC abnormalities detectable by immunohistochemistry showed atypical morphological features,and were associated with Chr Abn typical of HCC.Some of these tumors can recur and metastasize.It is likely that these tumors represent extremely well-differentiated HCC.SAA expression shows borderline significant correlation with inflammation and telangiectasia,but not with atypical morphological features or Chr Abn.
Category: Liver & Pancreas

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 223, Tuesday Morning


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