ECP 2023 Abstracts

S221 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 Cells and NKT cells at portal tracts are significantly lower in the pres- ence of fibrosis. Conclusion: Our data provide an overview of the association between intrahepatic immune cell composition and NAFLD severity. Overall, the numbers of helper T Cells, natural Treg cells, macrophages and B Cells significantly increase as disease progresses. NK cells and NKT cells play a potential role in the regulation of hepatic fibrosis. Funding: Canadian Liver Foundation Operating Grant E-PS-07-011 Granular cell tumour of the distal bile duct (GCT-DBD) and gall- bladder, a hidden tumour for radiologists, causing biliary obstruc- tive symptoms. Analysis of two cases diagnosed in a university hos- pital during a month M. De Uribe Viloria*, Z. Calixto Alvarez, A. Hidalgo Romero, A. Gabaldon, L. Blanco, C. Dopazo, M.T. Salcedo Allende *La Paz University Hospital, Spain Background & objectives: GCT are neoplasms derived from Schwann cells that can exhibit either benign or malignant behaviour. Most com- mon locations are the oral cavity, soft tissues and gastrointestinal tract. Biliary GCTs are extremely uncommon. We present two cases diag- nosed in our centre. Methods: We present two cases both diagnosed during the month of March 2023, one of distal bile duct GCT, the other of the gall- bladder, located in the neck. The diagnosis was achieved by using Hematoxilin-Eosin and immunohistochemical studies. From the clinical history we obtained clinical and radiological information. We sub-classified these lesions, according to Fanburg-Smith system, into benign and atypical. Results: A cases of a 73 year old female with recurrent episodes of acute choledocolithiasis and cholangitis, presenting with abdominal pain, and a 43 year old female presenting with a biliary colic due to cholelithiasis. In both cases radiological studies didn’t identify a mass. On gross examination of resected specimens, there was focal wall thickening. The histology revealed a tumour composed of cells resembling histiocytes, positive for CD68, NSE and s100. Necrosis and mitosis were absent. Following histological analysis. the former case was diagnosed as benign GCT–DBD. Spindle cells, vesicular nuclei with prominent nucleolus were identified in the latter warranting the diagnosis of atypical GCT of the gallbladder. Conclusion: CGTs of the biliary tract and gallbladder are uncommon and due to their rarity they may pose a diagnostic challenge. GCT should be considered in the differential diagnosis in patients presenting as acute-on chronic cholecystitis or recurrent cholangitis, with or with- out imaging evidence of tumours. To date, the diagnosis and classifica- tion requires a histological examination. The optimal treatment strategy for GCTs is yet to be defined, although, to date, surgical removal with wide margins and close clinical follow-up is recommended. E-PS-07-012 Heat shock protein 70 (HSP70), an accessible tool for differenti- ating biliary tract carcinomas from pancreatic adenocarcinoma? M. De Uribe Viloria*, A. Hidalgo Romero, Z. Calixto Alvarez, I. Bil- bao, M. Caralt, X. Merino, A. Gabaldon, M.T. Salcedo Allende *La Paz University Hospital, Spain Background & objectives: HSP70 expression has not been reported in neoplasias of the biliary tract (BT). HSP70 is a marker readily avail- able. We aim to demonstrate its expressions in BT carcinomas and whether it may be helpful to differentiate from pancreatic carcinoma (PDAC). Methods: We reviewed our files from 2014 to March 2023 and selected 30 cases, 10 intrahepatic invasive cholangiocarcinoma (Ih- iCC), 10 cholangiocarcinomas located in hepatic hilum and distal bile duct (HD-CC) and 10 PDACs. We examined the expressions of HSP70 by immunohistochemical staining (nuclear and cytoplas- mic) in all 30 cases and stablished three degrees of positivity: focal, patched and diffuse. Results: Our study included 30 patients (11 female, 19 male; median age 73.5). HSP70 nuclear staining was negative in 20% of Ih-iCC, 10% of HD-CC, and 50% of PDACs. Varying degrees of nuclear staining were found in 80% of Ih-iCC (Focal-10%, patched-60% and diffuse-10%), 90% of HH-DVB (Focal-20%, patched-60% and diffuse-10%), and 50% of PDACs (Focal-10%, patched-40% and diffuse-0%). Cytoplasmic staining was negative in 30% of HH-DVB, and 10% of PDACs. Vary- ing degrees of cytoplasmic immunoreactivity were observed in 100% of Ih-iCC (Focal-30%, patched-30% and diffuse-40%), 70% of HH-DVB (Focal-0%, patched-30% and diffuse-40%), and 90% of PDACs (Focal- 0%, patched-60% and diffuse-30%). Conclusion: Our study showed varying degrees of HSP70 expression in biliary tract carcinomas and PDAC, but no clear pattern for differential diagnosis was identified. Although more studies are needed, our results suggest that HSP70 immunostaining is not a useful tool in distinguish- ing these two types of cancer. To date, no immunohistochemistry study has been proven to be helpful in differentiating between these two dis- eases. Further research is warranted to identify more reliable diagnostic markers for biliary tract carcinomas and pancreatic adenocarcinoma. E-PS-07-013 Expression and prognostic significance of NY-ESO1 in gallbladder carcinoma A. Demirović*, S. Ramic, A. Ibukić, S. Čiček, T. Leniček, D. Tomas *UHC "Sestre milosrdnice", School of Dental Medicine, University of Zagreb, Croatia Background & objectives: Gallbladder cancer (GBC) is a malignancy with high mortality. NY-ESO1 (New York Esophageal Squamous Cell Cancer 1) is one of the most immunogenic Cancer Testis Antigens (CTAs). The aim was to assess potential clinical significance of NY- ESO-1 in GBCs. Methods: Study included 58 patients with GBC. Immunohistochemical analysis was performed on a representative paraffin block using mon- oclonal NY-ESO1 antibody (clone E978, Thermo Fisher Scientific). Cytoplasmic or nuclear staining of any intensity in ≥50% is considered positive. Clinicopathological data are statistically processed using sta- tistical program StatSoft Ver, 13.5.0.17 license AHN903D046305C- NET5-B (Tulsa, USA), with a statistical significance level of P<0.05. Results: The mean overall survival (OS) time was 19±35.4 months, and the median OS time was 7 months. Among classic histological characteristics Spearman’s correlation analysis confirmed that poorly differentiated tumours have a higher depth of infiltration (rs=0.414; P=0.001), and thus a higher clinical stage (rs=0.533; P<0.001). Expression of NY-ESO1 was recorded in 38 cases (69.1 %). COX regression analysis showed no significant difference in OS time after surgery depending on NY-ESO1 expression. Although NY-ESO1 did not show a correlation with any other observed clinicopathological parameter, relative risk of death within 12 months is slightly in favour of positive NY-ESO1 status. Conclusion: Two thirds of GBCs in our cohort showed positive expres- sion of NY-ESO1. NY-ESO1 has several clinical potentials such as serum NY-ESO1, vaccination and T cell receptor therapy. NY-ESO1 can serve as a predictive marker of immunotherapy as well as a serum marker in monitoring the response to the same. Patients with