Background. The distinction of hepatocellular carcinoma (HCC) from other neoplasms requires the use of immunohistochemistry. There are many usable markers, but not all of them are equally beneficial, and there is no unique antibodies panel. The aim of the study was to outline an immunohistochemical approach for the HCC diagnosis, as well as to recommend using synoptic report in routine practice.

Materials and methods. Formalin-fixed and paraffin-embedded tissue samples of 192 patients with documented hepatic neoplasm were collected from the National Centre of Pathology in Vilnius during 2003–2007. 64 samples with documented HCC, 11 metastatic adenocarcinomas (MA) and 20 benign neoplasms (BN) were selected for the study, for which immunostaining was performed with HepPar1, CD10, CD31, CD34, CK7, CK8 and CK20.

Results. HepPar1 was positive in all tumour grades; the sensitivity was 96.6%, and the specificity was 100%. CD10 stained 40/50 HCC; the sensitivity was 80%, and the specificity, 50%. CD10 was less specific compared with HepPar1 (p < 0.002); in cases of well-differentiated tumours immunoreactivity was seen more rarely (p < 0.01). The sensitivity of CD34 was 100%, and the specificity amounted to 97.1%. CD34 was the most sensitive compared with other markers
(p < 0.05). CD31 and cytokeratins immunoreactivity was seen in all types of tumours.

Conclusions. The combination of HepPar1, CD10 and CD34 confirms the diagnosis of HCC in most cases. HepPar1 is the most reliable marker for HCC differentiation. CD34 promises the diagnosis of HCC and distinguishes it from benign processes such as hepatic adenoma and focal nodular hyperplasia.

Keywords: hepatocellular adenoma (HCA), focal nodular hyperplasia (FNH), hepatocellular carcinoma (HCC), immunohistochemistry (IH)