ASS1+hepatocellular adenoma, a new and major subtype

Abstract

Introduction: A new hepatocellular (HCA) subgroup has been identified among unclassified HCA (UHCA: 10%) using 2 different approaches: gene mutation1 and proteomics2 and 2 immunohistochemical (IHC) methods: PTGDS1 and ASS12 Methods: We reviewed personal and consults resected HCA classified as UHCA, i.e. expressing LFABP, but not CRP, no abnormal GS allowing exclusion of known HCA subtypes. ASS1 was performed by IHC2. Results: We collected 22 personal and 11 consult HCA with ASS1 overexpression in the tumor in comparison with non-tumoral liver. All cases were women and were characteristic on H&E; 5 had borderline lesions, 2 with HCC foci. Clinical data were available in all 22 personal cases: mean age 38 (23-50); 20/20 on oral contraceptives (mean duration 19 years); 15 were overweight (9 with BMI > 30). 7/22 were admitted in emergency for severe hemorrhage and among them 2 had tumors < 5cm. Nodule was solitary in 11 cases; 2 had adenomatosis. Mean size of largest nodule was 7 cm (1.3- 23 cm). 6 patients had arterial hypertension and 5 diabetes. 11/22 cases tested were classified as shHCA1; 2 of them tested by IHC were PTGDS negative. In addition 2 cases classified as UHCA by gene mutation were ASS1+ with H&E characteristics of ASS1+HCA which finally represent 10% in our HCA cohort. Conclusion: ASS1+HCA is a characteristic subgroup both on clinical (hemorrhagic risk even for small tumors) and pathological ground. ASS1 is the 4th marker of the IHC HCA classification. 1Nault et al Gastroenterology 2017; 2Henriet et al Hepatology 2017.