ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 and showing deep anastomosing cords in the dermis. Tumour cells were polygonal with irregularly-shaped nuclei and numerous mitotic figures. Ulceration was found in four cases. Squamous cell differentiation was observed in five cases. Perineural invasion was observed in one case. Conclusion: This study underlines that EPC is a challenging diag- nosis and that careful clinicopathological correlation is the key to differentiate this malignant tumour from other skin tumours. PS-13 | Poster Session Digestive Diseases Pathology – Liver / Pancreas PS-13-001 Treatment with activin receptor-like kinase 5 inhibitor (ALK5i) differently affects collagen 1A1 deposition in mouse models of toxic and metabolically induced liver fibrosis M. Antolic*, O. Majstorović, V. Milutinović, S. Vidović Iviš, A. Ognjenović, A. Paravić Radičević, I. Glojnarić, S. Čužić *Selvita Ltd., Croatia Background & objectives: Chronic liver diseases of various aetiology lead to liver fibrosis/cirrhosis. Aim of the study was to explore pattern of de novo collagen 1A1 (COL1A1) deposition in two mouse models of liver fibrosis and to evaluate therapeutic effect of ALK5 inhibitor. Methods: Liver fibrosis was developed in 41-days CCl4 and 70-days high-fat diet induced models. Animals were treated with ALKi (SB525334); D21-D41 in CCl4 model and D29-D70 in NASH model. De novo collagen deposition was analysed by hydroxyproline content, COL1A1 content (anti-COL1A1 antibody, #72026, CST & digital pathology software, Visiopharm). Distri- bution of fibrous tissue was evaluated by NAFLD Activity and Fibrosis Score. Results: In both models, vehicle treated disease control mice, showed significantly higher liver hydroxyproline level and percent- age of COL1A1-positive area accompanied by formation of bridg- ing fibrosis, as compared to naïve animals. Treatment with ALK5i significantly decreased hydroxyproline levels and percentage of COL1A1-positive area in liver. There was no effect of ALK5i treat- ment on bridging fibrosis formation in CCl4-induced model. On the other hand, in high-fat diet model, decreased number of ani- mals with bridging fibrosis was observed following treatment with ALK5i; periportal and perisinusoidal fibrosis prevailed. Conclusion: It was shown that formation of bridging fibrosis in liver fibrosis model induced by high-fat diet can be influenced by ALK5i treatment. Influencing the pace of bridging fibrosis forma- tion could be of utmost clinical relevance, since disrupted intrahe- patic blood flow, due to presence of bridging fibrosis/cirrhosis, is a major cause of portal hypertension. PS-13-002 Utility of intraoperative pathology consultations during pan- creatic surgery and impact on final margin status: a single institution analysis N. Sina*, E. Olkhov-Mitsel, L. Sun, P. Roopchand, C. Rowsell, T. Truong *Sunnybrook Health Science Centre, Canada Background & objectives: Intraoperative consultations (IOCs) are widely used to assess surgical margins during pancreatic resections. The impact of this practice on patient management is often debated. Herein, we reviewed the utility of IOCs and its impact on final postop- erative surgical margin status. Methods: Retrospective review of all patients who underwent pancrea- ticoduodenectomy (Whipple) and distal pancreatectomy (DP) at our institution (2018-2020) was performed and data from pathology reports was recorded. From this cohort, cases of adenocarcinomas resected with Whipple surgeries were further analysed. A positive permanent margin (R1), including pancreatic, bile duct or other margins, was defined as margin involved by a known neoplasm. Results: During a 3-year period, 213 Whipple and 62 DP procedures were performed at our institution for neoplastic lesions. Of these, IOCs were completed for 112 pancreatic margins and 94 bile duct margins. Comparative analysis identified that although there was a significant difference in the frequency of margins submitted for IOC among four pancreatic surgeons (P<0.001), there was no significant difference in the postoperative final R0 rate (P=0.637 for Whipples and 0.653 for DP) for neoplastic lesions examined and for adenocarcinomas resected with Whipple surgeries, particularly (n=170, P= 0.612). Postoperative positive margins (R1) reported for Whipple adenocarcinoma cases also include other margins (n=41) that were not amenable to be assessed intraoperatively. Conclusion: Our data suggests that IOCs for margins did not seem to improve postoperative R0 on pancreatic resections. The current findings add to a growing body of studies that question whether intraoperative margin assessment of Whipple surgeries performed for adenocarcinomas contributes to reducing the risk of R1 or improving long-term patient outcomes. The significant difference in frequency of IOC requests for margins among surgeons also sug- gests the development or redefining of guidelines for IOCs during pancreatic surgeries. PS-13-003 Central histopathology review of hepatocellular carcinoma: impact of the WHO 2019 classification on histological diagno- sis and TNM staging K. Dimopoulou, D. Myoteri, D. Bouklas*, J. Kontis, P. Lykoudis, C. Nastos, G. Fragulidis, A. Vezakis, D. Dellaportas, M. Konstan- toulakis, N. Arkadopoulos, D. Tiniakos *Department of Pathology, Aretaieio Hospital, Medical School, National and Kapodistrian University of Athens, Greece Background & objectives: The updated World Health Organization (WHO) 2019 classification of hepatocellular carcinoma (HCC) introduces new histological subtypes with unique characteristics. Our aim was tumour reclassification and frequency estimation of new variants after review of histological slides from curative HCC surgical resections. Methods: We centrally reviewed all histological slides of 73 liver resection specimens from 73 patients with HCC (60 male, median age 72, IQR 64-76 years, BCLC stage 0-C) operated from 2001 to2018. Histological slides and reports were retrieved from the Department of Pathology, Aretaieion Hospital. All cases were reclassified according to WHO 2019 and re-staged according TNM 2017 system. Results: Twenty-two HCC (30%) were reclassified into new sub- types: 14 macrotrabecular-massive (19%), 4 steatohepatitic (5.5%), 2 chromophobe (2.7%), 1 lymphocyte-rich (1.4%), 1 neutrophil- rich (1.4%). Histological grade changed in 35/73 (48%) HCC: Ini- tial grade 1 n=21, 2 n=27, 3 n=25; revised grade 1 n=3, 2 n=48, 3 n= 22 (p<0.001). TNM stage was modified from 1 to 2 in 16/73 HCCs (p <0.001). The main histological pattern was solid (48%), trabecular (36%) or pseudoglandular (16%). Microvascular inva- sion was detected in 49/73 (67%) HCC. The non-neoplastic paren- chyma showed steatosis (42.5%), steatohepatitis (20.5%), chronic S134