[1638] Hepatocellular Carcinoma Arising from Hepatocellular Adenomas: A Clinico-Pathological Analysis

V Paradis, N Ferreira, S Dokmak, J Belghiti, P Bedossa, O Farges. Beaujon Hospital, Clichy, France

Background: Regenerative nodules are the underlying pathological conditions of hepatocellular carcinoma (HCC) in patients with cirrhosis. Hepatocellular adenoma (HA) may also transform into HCC without underlying liver disease. The objective of this study was to describe the main clinico-pathological characteristics of a series of HCC arising on HA in order to identify potential risk factors.
Design: Among 218 patients who had undergone liver resection with a pathological diagnosis of HA, 25 had features of malignant transformation. Macroscopic and microscopic features of the tumor (number, size of the overall tumor and HCC part, differentiation, presence of vascular invasion and hemorrhage / necrosis) and non tumoral liver were noted .
Results: Among the 25 patients, 17 were men (68%) and 8 were women (mean age 48 years). In 4 patients, multiple HA were present, 2 with adenomatosis. Metabolic syndrome was noted in 5 patients, all men. Mean size of the overall tumor was 11 cm (3-19), with 10.7 cm in males and 12.4 cm in females. Malignant transformation appeared as either single macroscopic nodule in 8 cases or as multiple microscopic foci in 17 cases. HCC was well-differentiated in 22 cases. In 3 cases, vascular invasion and/or satellite nodules were observed. Macroscopic foci of hemorrhage were present in 14 tumors (58%), and necrotic changes in 1 case. HA subtyping showed 13 telangiectatic, 7 unclassified, 3 with cell atypias, 1 steatotic and 1 indefinite. 8 tumors (32%) displayed a nuclear beta-catenin immunostaining suggestive of beta-catenin mutations (including 3 with cell atypias, 4 telangiectatic and 1 unclassified). All nuclear beta-catenin positive tumors were observed in males. Whereas size of the lesion was not significantly different between men and women, pattern of malignant transformation was different according to sex with a predominant microscopic multifocal form observed in males (82% vs 37%). Non tumoral liver displayed lesions consistent with NAFLD in 9 cases (36%) with no cases of significant fibrosis.
Conclusions: This series confirms the higher prevalence of malignant transformation in HA in males with telangiectatic subtype as the main risk factor. Malignant transformation occurs via 2 ways of progression, through a multifocal microscopic pattern predominantly observed in men and a macroscopic pattern predominantly observed in women. The relatively low prevalence of beta-catenin mutations indicates its poor predictive value as a malignant marker.
Category: Liver & Pancreas

Monday, March 22, 2010 2:30 PM

Platform Session: Section D, Monday Afternoon


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