Clinicopathologic and Molecular Characterization of Hepatocellular Adenomas (HCA) and Focal Nodular Hyperplasias (FNH)
A Gru, RK Pai, EM Brunt. Washington University in St. Louis, Saint Louis, MO
Background: HCA are benign neoplasms that occur in women exposed to exogenous estrogen. FNH are non-clonal proliferations that result from a dysregulation of angiopoietins. Inflammatory adenomas (IA), previously known as telangiectatic FNHs, can present a diagnostic difficulty between both FNH and HCA; they have recently been shown to have a characteristic mutation in gp130. Serum amyloid A (SAA) is overexpressed in IA. We aim to identify clinicopathologic features and molecular characteristics in HCA and FNH in a large American population.
Design: 42 cases of FNH, and 41 cases of HCA were retrieved from our files (1999-present). Clinicopathologic data included: age, gender, medications, body mass index (BMI), ethnicity, (BMI), liver tests, symptoms, tumor size, number, location, and all accompanying features (eg hemorrhage, rupture, etc). All cases were reviewed. Immunohistochemistry was performed in 25 cases for: Serum amyloid A (SAA), LFABP, b-catenin (BC), and Glutamine synthetase (GS). New potential molecular targets were also performed: VEGF, p16, CD68, and pSTAT3.
Results: The clinical follow-up available was similar for both groups (22 and 26 mos respectively); there were no adverse outcomes. Table 1 summarizes the clinical information and patterns of IHC. 3 LFABP mutated adenomas, 9 IAs, and 13 FNHs were tested with IHC. No activated BC adenomas were found. 4 unusual features were identified: 1) SAA+ was found in 2/13 FNHs, (2) GS, present in all FNH, was also diffusely present in 2/9 IA; 3) senescence (as determined by p16) was negative in all;; 4) BMI was not a discriminant feature of adenoma subtype.
Conclusions: This is the largest series of HCA with IHC reported in America. All HCA are found in obese patients; steatosis is present in nearly one-third in background liver. IHC may be a useful tool to distinguish FNH and IA, but lacks specificity. Senescence does not appear to play a role in ductular reaction in FNH or IA. In-Situ PCR is being evaluated.
|HCA (%)||FNH (%)||Statistics|
|BMI||32.5 (mean)||27.8 (mean)||0.009|
|Rupture / Hemorrhage||24 / 12||0 / 0||<0.05|
|NT Liver: Steatosis / SH||29 / 7.5||11 / 4||<0.05|