ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Incidental findings were identified in 11 specimens (6 men, 5 women): 1.-Squamous Cell Carcinoma (SCC) and Anal Intraepithelial Neoplasia (AIN) III;2.-SCC-in-situ;3.-AIN II-III;4.-Neuroendocrine Tumour (NET) poorly-differentiated;5.- Adenocarcinoma well-differentiated and AIN-II;6.-AIN-II;7.-AIN I-II;8.-Malignant Melanoma (MM);9.-Squamous Cell Carcinoma (SCC) and AIN-III;10.-AIN-II;11.-AIN-I. The resection-margins were positive in three cases, negative in three and could not be determined in five cases. Cases 1 and 2 had HIV. Cases with only AIN and cases 1 and 3 had clinical follow-up. The SCC-in-situ, margin expansion was performed. Case 9 received QT-RDT. NET and MM cases were treated at another centre. Conclusion: In our study the incidence of malignant lesions found incidentally in haemorrhoidectomy specimens was 2.47%. We consider that the surgical margins should be stained whenever possible and include a good representation of the material sent from the haemorrhoidectomy specimens, because although it is not frequent, we can find malignant lesions in these samples; and if so, we should try to provide as much histological information as possible. PS-07-046 Prognostic value of Decorin expression at the invasive front of colorectal adenocarcinomas D. Bouklas, A. Kostopoulou, A.C. Lazaris, N. Kavantzas, D. Tini- akos*, A. Gklavas, E. Kapeni, D. Karandrea, G.E. Thomopoulou *Newcastle University, Dept. of Pathology, UK; Nat. and Kapodis- trian University of Athens, Greece Background & objectives: Tumour budding (TB) and tumour- stroma ratio (TSR) are independent prognostic factors in colorectal carcinomas. Our aim was to assess the expression of small leucine- rich protein (SLRP) Decorin qualitatively and semi-quantitatively and to correlate this with TB, TSR and stromal desmoplasia. Methods: Eighty-six cases of colorectal adenocarcinoma were used to generate tissue microarrays that were stained with Masson trichrome, reticulin, orcein, and immunostained with pankeratin, decorin, CD8, and PDL1. Information about mismatch repair proteins (MMR) and Eosinophil leucocyte density were known. Decorin mRNA was assessed with rtPCR. Results: Cases were subdivided into 4 groups: Group Α 18% TB- HIGH/TSR-HIGH, Group B 14% TB-HIGH/TSR-LOW, Group C 21% TB-LOW/TSR-HIGH, Group D 40% TB-LOW/TSR-LOW. Decorin mRNA and protein expression were decreased in TB regions (p<0.003) and TSR regions (p<0.001). Decorin expression was also decreased in desmoplastic characterized areas. Decorin was a more sensitive indicator of stromal changes at the invasive front when compared with the morphologic assessment of collagen deposition and desmoplasia (p<0.001). There was no correlation between decorin expression and clinicopathologic parameters, MMR and Eosinophil density. Survival analysis showed no prog- nostic significance of Decorin protein and mRNA expression. Conclusion: Decorin expression is decreased at the tumour front and in both the TB and TSR annotated regions. Decorin is a more sensitive indicator of the initial stromal changes that take place at the tumour-stroma borders compared to morphological assessment of desmoplasia. Decorin expression appears of no prognostic value in colorectal adenocarcinomas in our cohort. PS-07-047 Simulated digital gastric cancer endoscopic biopsies and surgi- cal resections stained with PD-L1 IHC 22C3 pharmDx present similar PD-L1 expression when scored using combined positive score D. Monaco, J. Quiroz, E. Olander*, K. Kulangara, S. Hund, L. Peltz, E. Manna, S. Tabuena-Frolli *Agilent Technologies, USA Background & objectives: The dynamic range of PD-L1 expres- sion in endoscopic biopsies of gastric cancer (GC) is not as well- documented as that of surgical resections. This abstract aims to demonstrate the range of PD-L1 expression in simulated digital endoscopic biopsies (SBs) of GC. Methods: PD-L1 expression in GC SBs (simulated via ImageScope software from surgical resections stained with PD-L1 IHC 22C3 pharmDx) was evaluated in whole-slide images using combined positive score. Scores are determined by dividing the number of viable PD-L1-stained tumour cells and tumour-infiltrating immune cells by the total number of viable tumour cells. Totals are multi- plied by 100 and displayed as integers. Results: Of the 231 GC (including both gastric and gastroesophageal junction adenocarcinoma) SB samples, the average denominator, determined using QuPath, was found to be 11,742 tumour cells. In contrast, the average denominator of the 20 resection samples was 231,623 cells. Despite this greater than 19-fold difference in number of tumour cells, the distribution of combined positive score (CPS) scores remained similar in both sample types. SBs and surgical resections demonstrated similar distributions of CPS scores in terms of minimum, maximum, 25th, 50th, and 75th percentiles. In addition, the average CPS scores for SBs and surgical resections were approximately CPS 24 and CPS 25, respectively. Conclusion: These results suggest that, although the tumour cell counts of SBs are substantially lower than for resection samples, both present a dynamic range of PD-L1 expression. This suggests that GC SBs demonstrate a PD-L1 expression range similar to that of surgical resections, improving confidence in the evalua- tion of both small and large samples using CPS. PS-07-048 Impact of the Covid-19 crisis on digestive cancers operated on in a Tunisian hospital centre M. Ben Thayer, F. Khanchel, I. Helal, S. Elfekih*, R. Hedhli, E. Ben Brahim, R. Jouini, A. Chadli *Habib Thameur Hospital, Tunisia Background & objectives: Several studies have assessed the impact of the Covid-19 crisis on cancers around the world. However, no similar study has been conducted in Tunisia. We aim to Study the impact of Covid-19 crisis on the anatomopathological characteristics of different digestive cancers. Methods: We present a retrospective study conducted on cases of digestive carcinomas: colorectal (CRC), gastric (GC), pancreatic (PC) and gastrointestinal stromal tumours (GIST) operated on at Habib Thameur Hospital in between the first December 2016 and June 30, 2021.We subdivided these cases into two groups according to the date of their operation (before/during and after the lockdown) and we compared their histoprognostic characteristics. Results: These were 270 cases, including 83 diagnosed during and after confinement (30.7%). These were 219 cases of CRC, 22 cases of GC, 13 cases of PC and 16 GIST. Among the 83 cases operated starting from the lockdown, 12 were grade 3, 72 stage T3 or T4, 37 had lymph node metastases, one had visceral metastases, 27 presented vascular emboli and 31 had perineural invasion. Carcinomas operated on starting from the lockdown were statistically significantly correlated with visceral metasta- sis (p=0.01) and a more pejorative histological grade (p<10-3). S103