ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Conclusion: Historical skin wax models from Anatomical-Pathol- ogy Museums are priceless and unique tools to teach young medi- cal generations, especially in eradicated diseases, as Smallpox. Knowing how to recognize this entity is of major importance, since the world may unexpectedly face new epidemic waves, in various contexts, namely that of bioterrorism. PS-21-003 Pathology archives and applicability of immunohistochemistry – 40 years old myocardial infarction samples L. Carvalho*, C. Vilasboas, V. Almeida, A. Ladeirinha, A. Rod- rigues, A. Alarcão, M.R. Silva, T. Ferreira, R. Almeida, R. Henr- iques De Gouveia, V. Sousa *1 Anatomical Pathology Department, Hospitais da Universidade de Coimbra, Centro Hospitalar e Universitário de Coimbra; 2 Insti- tute of Anatomical and Molecular Pathology, Faculty of Medicine of the University of Coimbra, Portugal Background & objectives: Our group has recently determined that CD15, C9, C5b-9 and Fibronectin immunohistochemistry can be help- ful in Myocardial Infarction (MI) dating. This study aimed to verify antigen preservation for MI diagnosis dating after formalin-fixed par- affin-embedded (FFPE) myocardium stored over 30 years. Methods: We selected 19 FFPE MIs diagnosed in autopsies between 1970s-1980s from IAP-PM archives. Neutrophils absence/ presence was used for dating early/old MI <3days>. IHC panel discriminated between MI/non-MI cardiac tissue, namely CD15, C9, C5b-9 and Fibronectin. Two Pathologists calculated global expression to be compared with global expressions in 24 recent (2017-INMLCF) diagnosed MIs cases, using non-parametric Mann-Whitney test SPSS v27. Results: Samples reinclusion in new paraffin molding for new microtomes sectioning was performed and 3μm sections were submitted to IHC panel according with manufacturer recommendations for each antibody in BondMax platform. After considering global expression (intensity of expression x percentage of positive myocytes) of CD15 (U=202,500; p=0,531; N=43), C9 (U=214,500; p=0,739; N=43) and Fibronectin (U=147,000; p=0,077; N=43) no statistically significant differences were recognized between archival and recent MIs; C5b9 expression was significantly lower in MIs archived tissue over 40 years (U=138,000; p=0,027; N=43). Fibronectin expression was higher in infarcted tissue in all cases, when compared with normal myocytes. Conclusion: Our study highlighted performance of immunohis- tochemistry in archived MI paraffin blocks. It demonstrated that CD15, C9 and Fibronectin can be applied to FFPE archived sam- ples over more than 40 years, enabling and supporting future stud- ies on this material source. Dating MIs was the main goal and fibronectin revealed to be a robust biomarker either for distinguish- ing between ischemic necrosis and normal myocardium as well as tissue preservation standard biomarker. PS-22 | Poster Session Infectious Diseases Pathology PS-22-001 COVID-19 pathology in cases of co-morbidity with malignant tumours O. Reshetnikova*, S. Korenev, A. Ermakov, L. Rudiuk, S. Morozov *Immanuel Kant Baltic Federal University, Russia Background & objectives: COVID-19 infection cases with malignant neoplasms as co-morbidities are associated with increased risk of severe disease’ course and higher mortality. The aim of present study was to reveal organs’ pathologies induced by COVID-19 infection in patients with various cancers accom- panying illnesses. Methods: Autopsy examinations were performed in fifteen lethal cases of COVID-19 infection with malignant tumours co-mor- bidities. Clinical and laboratory tests data were recorded and analysed. Gross pathologies of lungs, other internal organs and brain were examined. Tissue samples were taken for histology. Malignancy diagnosis was confirmed in all cases by the onco- pathologist’s second opinion. Microscopy of H&E stained slides performed at x10,x20,x40. Results: Results have shown that six patients had concomitant haematological malignancies and nine ones suffered from car- cinomas of different localizations. In two cases the causes of deaths were a result of the tumour’s growth progression. Present study revealed multi-organ injuries in all cases, but the major- ity of patients had the most striking lungs pathology. Severe diffuse alveolar damage was diagnosed in thirteen cases with superimposed bacterial bronchopneumonia in two patients. His- tologically alveolar epithelial cells dystrophy and necrosis with parallel hyperplasia of type II pneumocytes, hyaline membrane formation, inflammatory infiltration with fibrin plugs in some airspaces were evident. Blood circulation disturbances were found in all autopsies of present study. Conclusion: The COVID-19 pandemic resulted in a global health crisis with the significant growth of morbidity and mortality. Concomitant malignancies contributed to organ’s insufficiency and fatal outcomes. Effective clinical management must be based on the fundamental knowledge of the pathogenesis and pathology of infection combined with neoplastic growth. Post- mortem examination is an essential tool in understanding the damages due to this novel infection. Further investigations of the underlying neoplastic diseases’ role in lethal outcomes of the COVID-19 are considered essential. PS-22-002 Mast cells induce fibrosis and thrombosis in lung tissue sam- ples of patients infected with SARS-CoV-2 virus B. Lopuhaä*, L. Wismans, W. De Koning, H. Moeniralam, M. Van Oosterhout, T. Kuiken, R. Endeman, D. Mustafa, J. von der Thüsen *Erasmus Medical Center, The Netherlands Background & objectives: COVID-19 lung tissue shares simi- lar histomorphological features with chronic lung allograft dis- ease, suggesting activation of auto-immune related pathways in COVID-19. Therefore, we analysed the mRNA expression of auto-immune-related genes in post-mortem lung tissue from COVID-19 patients. Methods: Formalin-fixated, paraffin-embedded post-mortem lung tissue samples of COVID-19 patients were used for tar- geted gene expression profiling using the autoimmune panel of NanoString technology. To validate the results, multiplex immu- nofluorescence for tryptase and chymase was applied. Lung tis- sue samples from influenza patients were used as a control group. Results: Immune infiltration was broadly similar between COVID-19 and influenza patients. Upregulation of genes related to mast cells (TPSAB1/TPSAB2, CPA3, and HDC) was identi- fied in COVID-19. This finding was strengthened by multiplex S160