[1464] Useful Pathologic Features To Distinguish Telangiectatic/Inflammatory Hepatocellular Adenoma from Other Benign Hepatocellular Tumors

AA Suriawinata, KH Lim, MI Fiel, L Qin, S Ward, DJ van Leeuwen, SN Thung. Dartmouth-Hitchcock Medical Center, Lebanon, NH; Singapore General Hospital, Singapore, Singapore; Mount Sinai Medical Center, New York, NY

Background: Telangiectatic/inflammatory hepatocellular adenoma (TIHA) of the liver, previously described as telangiectatic focal nodular hyperplasia, is a neoplasm that had been considered as a variant of focal nodular hyperplasia (FNH). Recent studies indicated that TIHA are monoclonal; therefore, TIHA was reclassified as a variant of hepatocellular adenoma (HA). Distinguishing one from another remains problematic when the specimen is small and clinical studies are inconclusive. To clarify TIHA diagnostic features, we studied gross morphology, histologic and immunohistochemical features of these benign tumors.
Design: We identified 13 archived cases (11 resections, 2 biopsies) of TIHA between 2000-6. For comparison, 13 resections of FNH and 16 of conventional HA were selected. Gross morphology and histologic features were evaluated for the presence of unpaired arteries, dilated sinusoids at least 30% of the lesion, trabecular thickness, cellular atypia, portal tract like structures (PTLS) containing dystrophic arteries, PTLS with bile ductules, steatosis in lesion and adjacent tissue, chronic inflammation; and detailed study of the vasculature including presence of thin and thick walled vessels, vessels draining directly into the sinusoids and clustered ectactic vessels. Selected representative sections were immunohistochemically stained for CK7, MIB-1, p53 and serum amyloid A (SAA).
Results: In addition to the characteristic soft and hemorrhagic gross morphology and the absence of central scar, we identified four histologic features useful to diagnose TIHA(p<0.001): 30% of dilated sinusoids, PTLS with bile duct, vessels draining directly into sinusoids and ectatic thin-walled vessels. Other features of TIHA, not statistically significant, but aid to the distinction of TIHA vs. HA are chronic inflammation and presence of thick walled arteries; and TIHA vs. FNH are cellular atypia and presence of unpaired arteries. CK7 reacted to ductular epithelium in TIHA and FNH, but absent in HA. SAA were positive in majority of TIHA and HA, but negative in FNH. The intensity of SAA staining correlated with the degree of inflammation in TIHA. MIB-1 and p53 were not helpful in differentiating these tumors.
Conclusions: We have identified a subset of pathologic features that are useful to the diagnosis and distinction between TIHA from other benign hepatocellular tumors.
Category: Liver & Pancreas

Tuesday, March 10, 2009 9:30 AM

Poster Session III # 166, Tuesday Morning