ECP 2023 Abstracts

S388 Virchows Archiv (2023) 483 (Suppl 1):S1–S391 13 tubules ("onion skinning") were absent. The patient was no recurrences during the 8 months of postoperative follow-up. E-PS-24-085 Molecular classification of urothelial carcinomas of the bladder: study of the north-east population of Morocco M. Zaryouhi*, A. Douida, H. El Fatemi *Hassan II hospital University, Morocco Background & objectives: Molecular classification of bladder car- cinoma is an ongoing area of focus in modern oncology. Subtyping is important because it predicts patient outcomes. Our study aims to establish a molecular classification of bladder carcinoma and correlate it with classical histoprognosis factors. Methods: We included in this retrospective study covering the period from 2012 to 2019 patients with urothelial bladder carcinoma that infil- trate the chorion (pT1 at least). Lesions were classified according to the WHO 2004 classification. Stage, grade, molecular subtypes, recur- rence, and survival were studied. Results: The cohort comprised of 243 patients with a mean age of 62 years. The histological type was urothelial carcinoma, and it infiltrates the muscle in 51%. The most frequent tumour stage is pT1 followed by pT2. An immunohistochemical study was performed in 82 patients for molecular classification according to the approach reported by the MD Anderson group. 39.2% of the cases were classified as Basal sub- type, 27.3% of the cases as Luminal subtype and 21.5% of the cases as p53-positive subtype, 12% of the cases were not classified. At the end of this classification, correlations between molecular subtype and histoprognosis factors have been established. Conclusion: Molecular subtypes of urothelial carcinoma of the bladder have been associated with distinct prognoses and responses to therapies in retrospective studies. If validated, molecular profiling could be inte- grated into the clinical management of this cancer. Nevertheless, histol- ogy will keep an important place to allow a rapid diagnosis at lower costs, but a comparison of the two aspects, molecular and histological, will be essential. Ideally, both classifications should probably be used. E-PS-25 | E-Posters Other Topics E-PS-25-001 HEG1 expression in mesothelial tumours M. Dicleli*, A. Keleş *Cizre State Hospital, Turkey Background & objectives: Sialylated protein HEG homolog 1(HEG1), is a mucin-like membrane protein found on mesothelioma. It can detect even sarcomatoid and desmoplastic mesothelioma. We evaluated HEG1 in mesothelial and nonmesothelial tumours to understand the impor- tance of HEG1 expression in determining mesothelial origin. Methods: Our study included 69 cases of pleura, peritoneum and testis diagnosed with 64 mesothelioma, 3 well-differentiated mesothelial tumour, 2 atypical mesothelial proliferation Also, 25 non-mesothelial (various organ carcinoma metastases, sarcoma and other tumours) tumours were included. Staining scores were calculated for IHC by adding the number of categories for the staining intensity and the staining extension. Results: HEG1 expression was observed in 68 of 69 mesothelial cases. Although HEG1 expression was observed in most of mesothelio- mas, lower scores of HEG1 expression were observed in sarcomatoid mesotheliomas (p=0,043). Higher scores of HEG1 expression were observed in low-grade epithelioid mesotheliomas than in high-grade epithelioid mesotheliomas (p=0,049). None of the non-mesothelial tumours (3 pulmonary adenocarcinoma, 3 squamous cell carcinoma, 2 papillary thyroid carcinoma, 2 renal cell carcinoma, 1 large cell carcinoma, 2 colorectal carcinoma, 3 breast carcinoma, 1 urothelial carcinoma, 2 ovarian serous carcinoma 1 sarco- matoid carcinoma, 1 large cell neuroendocrine carcinoma, 1 malignant melanoma, 1 myxoinflammatory fibroblastic sarcoma, 1 solitary fibrous tumour, 1 Ewing sarcoma) HEG1 expression was not observed. Conclusion: In all of our cases with surface epithelium, the surface epithelium was immunoreactive with HEG1. HEG1 was observed with higher scores in epithelioid mesotheliomas compared to sarcomatoid mesotheliomas and in low-grade epithe- lioid mesotheliomas compared to high-grade ones. While HEG1 was positive in mesothelial tumours, it was negative in all non-mesothelial tumours. HEG1 was observed with high sensitivity and specificity in mesotheliomas. HEG1 may be a useful marker to distinguish between mesothelial and non-mesothelial tumours, to show mesothelial origin. E-PS-25-003 Reducing errors and lost samples in the AP lab through imple- menting preprocessor scanning S. Gable* *Cardiff and Vale University UHB, United Kingdom Background & objectives: Procedures exist in every histology labora- tory to protect samples in the diagnostic process, however, errors still occur. Cardiff and Vale University Health Board implemented a new system to ensure positive identification and tracking of samples and reduce/eliminate sample loss. Methods: CVUHB conducted an observational study with a new system and workflow that enables pre-processor scanning of histology cassettes in tissue processor baskets. This system reduced manual tasks that are prone to human error, while enabling accurate and definitive monitoring of pro- cessing schedules, reagents used, times, and user activities to enhance the traceability of samples throughout the laboratory until final archiving. Results: Introducing the new workflow at CVUHB from October 2022 to January 2023 resulted in a reduction in time associated with reconciling lost/misplaced samples in the lab workflow. This reduction went from as long as three days to as short as a couple of hours (nearly 82% reduction). All misplaced samples were properly recognized and corrected within 2.5 hours as a consequence of the new system workflow and tracking data- base. There were 96 potential touch points (prone to error) eliminated in the preprocessing workflow. Time associated with scanning cassettes and baskets was reduced by 91%. These improvements created a more efficient laboratory workflow, reduced stress, and enhanced turnaround times. Conclusion: Introducing preprocessor sample scanning to the histology lab delivers several advantages beyond sample tracking and patient safety. As cancer incidence rates grow, sample tracking is important to provide a necessary level of patient safety. It also contributes to consistently high sample quality and more efficient laboratory workflows with fewer human errors. This is essential considering the shortage of qualified personnel to support laboratory procedures. The new workflow was more effective at sample tracking and reconciliation than the prior manual workflow. E-PS-25-004 Use of virtual microscopy in university teaching of pathological anatomy: comparative study with optical microscopy S. Gharbi*, D. Bacha, I. Mallek, E. Benammou, M. Hajri, H. Mestiri, A. Lahmar, S. Ben Slama *Department of Pathology, Armand Trousseau Hospital-Sorbonne University, Tunisia Background & objectives: Interest in virtual microscopy (VM) as a means of simulation learning in pathological anatomy is growing. The objective of our work was to compare the learning by MV to that by MO, in terms of skill acquisition and student satisfaction levels.