ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 PS-24-004 Direct scanning of selected FFPE blocks to reduce workflow costs of routine FFPE controls in histopathology A. Nguyen, M. Algoe, J. Giang, J. Van Brakel, M. Nap, F. Van Kemenade* *Dep of Pathology, Erasmus MC, Rotterdam, The Netherlands Background & objectives: Pathology departments face high costs of slide cutting, staining and coverslipping. We employed a large field-of-view confocal microscope allowing to image thick specimens (Histolog® Scanner) for scanning FFPE blocks to investigate whether this could reduce the number of slide prepared. Methods: Lung (n=47) and pancreas (n=23) FFPE blocks were imaged with the Histolog Scanner. Pathologists, residents and one grossing room technician were asked to diagnose independently in confocal images if the block is exclusively composed of normal tissue or not. Rate of image rejection prior diagnosis due to insufficient image quality is monitored for further costs saving assessments. Results: Rate of image rejection were 17% for pancreas and 23% for lung tissues reducing the potential cost savings (these blocks would be processed whatever their content in a routine practice). On the non-rejected images, observers were able to recognize tissue features in FFPE block images despite loss of nuclear detail and lack of colour nuances compared to H&E slides. Accuracy to define that the blocks are exclusively composed of normal tissue yielded high scores for both tissue types: overall sensitivity/specificity of 96%/100% for pancreas (2 pathologists, 1 resident) and of 93%/83% for lungs (4 residents, 7 pathologists, 1 grossing room technician). Similar performances between the three observer populations were found. Conclusion: Direct image assessment of FFPE blocks by His- tolog® Scanner seems to yield acceptable images compared to H&E slides. Preliminary results showed that good performance of FFPE block screening can potentially be achieved for pancreas and lung tissues with very high sensitivity before the preparation of histology slides. This allows potential cost reduction in slide preparation and infrastructure costs for slide storage. PS-24-005 Audit of pathology quality assurance programmes: assessing efficacy and workload D. O’Dwyer*, M. Agarwal *University Hospital Monklands, United Kingdom Background & objectives: Studies have highlighted significant discrepancies between original and review pathology diagnoses. Quality assurance programmes can improve reporting accuracy. This audit assessed the effectiveness of quality assurance programmes within a single institution and determined the frequency of discrepancies in reporting. Methods: Retrospective review of cases collected over a one year period was performed. Cases were continuously recorded during this time following review at MDT or clinical meetings and review of randomly selected cases. Frequency of overall reporting errors was calculated and chi square analysis was performed to detect potential disproportionate review of specific specialties. Results: The continuous quality assurance programme ensured review of 7.7% of the total histology and cytopathology workload over 1 year. Proportionally more histology cases were reviewed compared to cytopathology (p=<0.00001). Randomly assigned review of cases accounted for only 9.7% of the quality assurance programme workload whilst the rest came from review at MDT or clinical meetings. The proportionate percentage of cases reviewed as per overall spe- cialty workload was significantly different: urology 49.3%, respira- tory 37.3%, H&N 16.7%, skin 9.0%, gynaecology 6.2%, gastroin- testinal 4.4% and breast 1.7% of cases. There was complete diagnostic agreement in 94.9% of reports and errors regarded as potentially clinically significant were recorded in 0.9% of cases overall. Conclusion: Our quality assurance programme ensured review of a significant proportion of overall workload compared to other studies (1.3-8.9%) with comparatively low significant error rates (0.8-5.3%). Within our institution the combined approach of random plus focused case review effectively detects reporting discrepancies and is pragmatic and efficient. To our knowledge we are the first to assess whether cases reviewed within a quality assurance programme proportionately reflect over- all workload. This information is important to improve effective- ness of quality assurance programmes. PS-24-006 Extrapulmonary POU2F3-positive small cell carcinoma is asso- ciated with variable neuroendocrine marker expression and gallbladder location M.H. Nam*, C. Chen, Y. Zhang, J. Lee, Y. Kao *Department of Pathology, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan Background & objectives: POU2F3 is recently identified as the defin- ing biomarker of a subset of small cell carcinoma (SmCC) of lung asso- ciated with neuroendocrine-low immunoprofile and poor prognosis. Here, we aimed to explore the presence of POU2F3-positive extrapul- monary SmCC and its clinicopathologic characteristics. Methods: Thirty-four extrapulmonary SmCC from various organs were collected for POU2F3 immunohistochemical stain- ing. The age, sex, primary location, histology (pure versus com- bined SmCC), and the expression of TTF-1 and available neu- roendocrine markers, including synaptophysin, chromogranin A, and/or INSM1, were recorded. To examine its specificity, we also performed POU2F3 staining on 849 cases of 32 different histo- types, including carcinomas, lymphomas, and sarcomas. Results: POU2F3 immunostaining was positive in 5 (14.7%) extrapulmonary SmCC, originating in the gallbladder (n=3), urinary bladder (n=1), and uterine cervix (n=1). The patients ranged from 52-89 years old. Histologic types were pure SmCC in 4 and combined urothelial carcinoma/SmCC in 1. Synaptophysin was positive in 4 (80%) cases, ranging from strong/diffuse to weak/focal. INSM-1 was positive in both cases with available results (focal/weak and diffuse/moderate in one each). Chromogranin A and TTF-1 were negative. In other tumour types tested, POU2F3 stain was mostly negative, except focal staining in 1 ductal carcinoma in situ of breast (3.4%), 2 gastric adenocarcinomas (1.2%), and 1 invasive carcinoma of breast (0.7%). Conclusion: Aside from pulmonary SmCC, POU2F3 expression was also found in a minority of extrapulmonary SmCC. Although the case number was small, our data suggested a potential predi- lection of gallbladder location and a wide range of synaptophysin and INSM1 expressions. Among different tumour types, POU2F3 is relatively specific to SmCC and may serve as a valuable addi- tion to the diagnostic panel for SmCC. Further study is needed to investigate the prognostic and therapeutic significance of POU2F3 expression in extrapulmonary SmCC. S165