ECP 2023 Abstracts

S223 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 E-PS-07-018 The spectrum of Hepatocellular carcinoma precursor lesions: stemness and epithelial-mesenchymal plasticity J. Espírito Santo*, A.F. Ladeirinha, A. Alarcão, E. Strelet, M. Reis, R. Santos, L. Carvalho *Adult Liver Transplantation Unit, Coimbra Hospital and University Centre, Portugal Background & objectives: Dysplastic foci (DF) may evolve to low-grade/high-grade dysplastic nodules (LGDN/HGDN) and sub- sequently to hepatocellular carcinoma (HCC). Hepatic progenitor cells (HPC) undergo heterogenous differentiation, displaying epi- thelial-mesenchymal plasticity (EMP). Expression of HPC/mesenchymal markers was analysed in a spectrum of HCC precursor lesions. Methods: A series of 5 regenerative nodules (RG), 8 DF, 12 LGDN and 5 HGDN was collected from 21 patients (19 were cirrhotic) under- going liver resection/transplantation. WHO 2019 histopathological cri- teria, proliferation/apoptotic markers (Ki67, p53), HPC/cholangiocytic markers (CK7, CK19, EpCAM/BerEp4) and mesenchymal markers (alpha-smooth muscle actin - ASMA - and vimentin) expression were evaluated in lesional cells (Lc) and perilesional hepatocytes (Plh). Results: Higher perilesional ductular reaction, with important HPC markers expression, was observed in DF and LGDN. RG and DF dis- played relevant Lc expression of EpCAM, CK7, ASMA and vimentin, while HPC/cholangiocytic markers rose from RG to DF and mesenchy- mal markers expression declined. EpCAM and ASMA expression in Lc decreased from DF to LGDN to HGDN, while EpCAM expression in Plh was greater in LGDN than in DF (p<0.05). HGDN showed higher expression of CK7+ Plh than LGDN (p<0.05). Lc vimentin expression was higher in HGDN than in DF (p<0.05) and increased across DF, LGDN and HGDN, while LGDN showed higher Plh vimentin expres- sion than HGDN (p<0.05). Conclusion: Stemness and EMP seem to have an important role in the early steps of hepatocarcinogenesis. The applied immunohistochemical panel, following WHO advise, allowed to understand the relationship between HPC activation and EMP, determined by liver microenviron- ment. Further studies will help to determine different ways of targeting HPC and EMP to effectively modulate HCC development and prognosis. Funding: ROCHE- APEF (Portuguese Association for the Study of the Liver) research grant. E-PS-07-019 Hepatic adenomatosis with malignant transformation in a young patient with a congenital extrahepatic portosystemic shunt (Aber- nethy malformation) A. Felšöová*, O. Fabián, L. Janoušek, E. Sticová *Clinical and Transplant Pathology Centre, Institute for Clinical and Experimental Medicine, Prague, Department of Histology and Embry- ology, Second Faculty of Medicine, Charles University, Prague, Czech Republic Background & objectives: Abernethy malformation (AM) is a rare congenital anomaly of the venous system characterized by presence of intrahepatic or extrahepatic porto-systemic shunts. The condition yields an increased risk for development of hepatic tumours such as hepatocellular adenoma (HCA) or carcinoma (HCC). Methods: We report a case of hepatic adenomatosis in an 18-year-old female with AM. CT scan detected multiple hepatic tumours with mor- phology corresponding to HCA or focal nodular hyperplasia (FNH). Due to the progression of the size and number of the foci, the patient was indicated for a liver transplantation. Results: In the gross findings, 12 spherical, sharply demarcated tumours were found in both lobes. Histologically, multiple HCAs were found showing cytological atypia of a various degree. In several areas, transition to well differentiated HCCs with infiltrative growth patterns were found. Immunohistochemistry of these lesions showed an aberrant nuclear positivity of beta-catenin and a diffuse cytoplasmic positiv- ity of glutamine-synthetase. Apart from that, several foci with FNH- like morphology were detected. The surrounding hepatic parenchyma showed unevenly distributed and fibrotic portal spaces with numerous and tortuous interlobular arteries and hypoplastic interlobular veins. Conclusion: AM is a rare vascular anomaly, the knowledge of which is important especially due to increased risk of liver tumours. We pre- sented the case of the patient with this disease and the occurrence of multiple HCAs with beta-catenin mutation and transformation to HCC. E-PS-07-020 Comparison between imaging and pathological findings in liver transplant recipients with hepatocellular carcinoma in the setting of chronic liver disease/cirrhosis: a retrospective study of 26 cases from 2017 to 2023 C. Gouta*, P. Panas, E. Katsiki, V. Georgopoulou, K. Gianna, E. Sina- kos, G. Tsoulfas *Department of Histopathology, Hippokration General Hospital of Thessaloniki, Greece Background & objectives: Computed Tomography Scan and Mag- netic Resonance Imaging are used in a regular basis in the follow-up of patients with chronic liver disease and cirrhosis and are essential tools for the evaluation process and placement in the liver transplant waiting list. Methods: We conducted a retrospective study that included 26 patients with hepatocellular carcinoma who underwent liver transplantation from 2017 to 2023 in our hospital. The malignancy classification, the number of foci and the maximum diameter of the neoplasm according to the last imaging technique before transplantation were recorded and compared to the respective pathological findings in the explant. Results: All 26 recipients (24 males and 2 females) had cirrhosis due to late-stage chronic liver disease, specifically, alcoholic/non-alcoholic fatty liver disease, primary biliary cholangiitis and chronic viral hepa- titis (HBV, HCV and combined HBV/HDV). Pathological and imag- ing results were identical in 69,23%, 42,30% and 23,08% of the cases regarding the type of malignancy, the number of foci and the maximum diameter respectively. In 6 of the 26 cases the imaging techniques either misdiagnosed the neoplastic disease as benign or were not able to iden- tify its type. Furthermore, both the number of foci and the maximum diameter displayed a mean deviation of no statistical significance. Conclusion: According to our study both Computed Tomography Scan and Magnetic Resonance Imaging are equally reliable techniques for the follow-up of transplant candidates and their eligibility evaluation based on Milan Criteria. Additional factors such as the number of days between the imaging and the transplantation, the time needed for the explant fixation and the variety of methods used by the radiological laboratories involved were considered throughout the study and are extensively discussed. E-PS-07-021 Disease patterns and entities in primary medical and tumour liver consult cases highlight challenging areas in diagnostic hepatopathology I. Grypari*, I. Vlachos, E. Stoupi, D. Karandrea, D. Myoteri, D. Tiniakos *Department of Pathology, Aretaieion Hospital, Medical School, National and Kapodistrian University of Athens, Greece Background & objectives: Difficult liver pathology cases often require expert review for optimal patient care. We reviewed consult cases received in our reference centre aiming to highlight challeng- ing areas in hepatopathology that may benefit from consultation and focused educational activities.