ECP 2023 Abstracts

S227 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 E-PS-07-032 Peri-ampullary EBV-associated lymphoepithelioma-like carci- noma: a case report E. McGrath*, K. Ryan, N. Swan, L. Clarke *St Vincent’s University Hospital, Dublin, Ireland Background & objectives: Lymphoepithelioma-like carcinomas are rare tumours composed of undifferentiated malignant epithelial cells with characteristic lymphoid stroma that resemble non-keratinizing nasopharyngeal carcinoma, undifferentiated subtype (previously lym- phoepithelioma). The majority of cases occur in the head and neck are associated with Epstein-Barr virus (EBV). Methods: Case report: We report a case of a 50-year-old man who underwent a pancreatoduodenectomy (Whipple resection) for a primary peri-ampullary EBV-associated lymphoepithelioma-like carcinoma. Results: An oesophagogastroduodenoscopy (OGD) revealed a tumour mass present in the peri-ampullary region of the duodenum. A biopsy showed a poorly differentiated malignant epithelioid neoplasm with lymphoid stroma that was positive for EBV by in-situ hybridisation. A pancreatoduadenectomy (Whipple resection) was carried out after neoadjuvant chemotherapy. Pathology: Macroscopically, a 24mm solid mass was present in the peri-ampullary region of the duodenum and an adjacent positive peri-pancreatic lymph node was identified. Histology showed extensive residual poorly differentiated carcinoma with lym- phoid stroma extending into periduodenal soft tissue with perineural invasion. Malignant epithelial cells showed positive EBV expression by in-situ hybridisation and mismatch repair proteins (MSH-2, MSH-6, MLH-1 and PMS-2) were intact on immunohistochemistry. Conclusion: Peri-ampullary EBV-associated lymphoepithelioma-like carcinoma is an exceedingly rare primary malignancy. To our knowl- edge, only one other case has been described in the literature at this site. We compare our case to the single previously reported case and review the current literature and classification of lymphoepithelioma- like carcinomas. E-PS-07-033 GATA3 expression in pancreatic ductal adenocarcinoma: an immunohistochemical analysis of 140 cases G. Menetlioğlu*, P. Bağcı Çulçi, E. Bozkurtlar *Marmara University, Departmant of Pathology, Turkey Background & objectives: This study investigates GATA3 incidence in pancreatic ductal adenocarcinoma (PDAC) and its impact on differ- ential diagnosis, given its importance in the TGF-B signalling pathway and limited research in this area. Methods: A total of 140 patients diagnosed with PDAC between 2012- 2021 were included in the study. Microarray blocks (TMA) were cre- ated from each tumour using a 0.6 mm punch and GATA-3 immuno- histochemistry was applied to these blocks. Tumours were evaluated for nuclear immunoexpression. Results: Of the 140 patients included in the study, 66 were female and 77 were male, with a mean age of 67. GATA3 immunohistochemistry did not reveal nuclear immunoexpression in any of the cases. Conclusion: Some studies in the literature report that GATA3 is posi- tive in some cases of PDAC, however, in our study, GATA3 immu- noexpression was not detected in any of the 140 cases. These results may limit the use of GATA3 expression in differential diagnosis due to the lack of a specific immunohistochemical marker for PDAC. E-PS-07-034 Hepatic epithelioid haemangioendotheliomas: immunohistochemi- cal profile and expression of CAMTA1 for its differential diagnosis M.d.R. Mercado Gutierrez*, M.L. Gomez-Dorronsoro, B. Aguiar, I. Amat, R. Beloqui, C. Cerezo Aguirre, A. Lopez *Navarra’s Universitary Hospital, Spain Background & objectives: Hepatic epithelioid haemangioendothe- lioma (HEHE) is a rare tumour that have WWTR1-CAMTA1 and YAP- TFE3 fusion gene in 90% and 5% respectively. Our study aimed is to describe the immunohistochemical pro- file of HEHEs and the utility of CAMTA1 also in other digestive haemangioendotheliomas Methods: We collected four cases diagnosed as epithelioid haemangi- oendotheliomas in digestive tract from 2004 to 2023 in Navarra’s Uni- versitary Hospital (Spain). One of them underwent a surgical resection. Immunohistochemistry (IHC) was performed using CAMTA1, TFE3, citoqueratin7, CD31, CD34, EGR, HepPar1 in formalin fixed paraffin embedded blocks. Clinical data, epidemiologic features, treatment methods, and clinical courses, were reviewed through electronic medical records. Results: Two cases were diagnosed as primary HEHE (Case1 and 2) . The others were located in spleen(Case3) and small intestine(Case4). Case1: 73 year old male. Radiological study consistent with cholangocarcinoma. IHC: TFE3 positive nuclear and diffuse, CAMTA1 negative. The resected specimen showed a multifocal HEHE with portal tract and vascular involvement. Case 2: 50 year old woman. Scan showed a unique hepatic nodule consistent with primary metastatic cervical cancer. IHC: TFE3 negative and CAMTA1 positive. Citoqueratin 7 and vascular markers (CD31, CD34, ERG) were strong and diffuse positive in both cases and they were negative for HepPar1. Case 3 and 4: TFE3 negative and CAMTA1 positive. Conclusion: Histologically, the HEHE can mimic metastatic carcinoma, angiosarcoma, hepatocellular carcinoma, and cholangiocarcinoma. Immunohistochemical profile shows expression for vascular markers (ERG, CD 31 and CD34) Given its epithelioid morphology, strong expression for citoqueratin 7 should be carefully assess specially in clinical and radiological finding suspicious for cholangiocarcinoma. CAMTA1 is a helpful marker for diagnosis of hepatic HEHE as TFE3. E-PS-07-035 Uncommon aetiology of pancreatic mass: a case report S. Moqran*, H. Abdoulaye Biyou, F. Harmouch, R. Ben Tayab, L. Tahiri, L. Chbani *University hospital hassan II, Morocco Background & objectives: IgG4-related autoimmune pancreatitis (AIP) is a chronic inflammatory disease of the pancreas with a dis- tinct histological. his diagnostic remains challenging as some features overlap with pancreatic cancer. We present a case of IgG4-related AIP mimicking pancreatic cancer. Methods: 70-years-old male patient presented with epigastric pain, radiating to the entire abdomen with an unquantified weight loss. Mag- netic resonance cholangiopancreatography (MRCP) showed a mass with 28 mm long axis, in the head of the pancreas with pancreatic duct dilata- tion. Thus, he is presumed to have a pancreatic neoplasm and underwent pancreatic resection without a definitive preoperative diagnosis. Results: In terms of clinical presentation, imaging characteristics, and laboratory parameters, IgG4-related AIP can resemble pancreatic cancer. Thus, histopathological studies remain the gold standard for a definitive diagnosis, that may show a diffuse lymphoplasmacytic infil- trate with a storiform fibrosis. On immunohistochemistry, the majority of plasma cells are positive for IgG4 (>50 per high-power field [HPF]). In our case, the gross appearance was indistinguishable from a pan- creatic neoplasm. The histologic diagnosis allowed us to suggest the diagnosis of IgG4-related AIP and the immunohistochemical diagnosis confirmed the diagnostic. Conclusion: It is critical to distinguish pancreatic cancer from IgG4- related AIP due to theirs completely different prognosis and therapy.