ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 Methods: 116 postoperative GISTs were assessed in terms of histology and immunohistochemistry (CD117, DOG1, Ki67 and PHH3). The size of the tumours were based on macroscopic and radiological data. Statistical analysis included non-parametric Wilcoxon test was used to compare continuous variables and chi- square test to compare proportions. Spearman correlation coef- ficient was used to calculate correlation. All test were two sided. Results: Cycline D1 was expressed in 72/116 cases (25 LG tumours according to ESMO criteria and 47 HG tumours ) – p>0,099. No correlation was found between cycline D1 expression and PHH3 expression (rho=-0,07, p=0,444) mitotic index (rho=-0,12, p=0,216). |The correlation was found between cycline D1 expres- sion and size of the tumour (mean size of the tumour in cycline D1 positive group = 7,2cm vs cycline D1 negative group = 9,4cm; rho=-0,20, p=0,03) Conclusion: The immunohistochemical expression of cycline D1 does not correlate with mitotic index and PHH3 and Ki67 immunohistochemical expressions in GISTs. It does not discriminate between LG and HG tumours. Hence it does not influence the risk stratification of GISTs as measured in tissue material. The correlation between cyclineD1 expression and smaller size of the tumour is observed. It is to be established upon observational studies whether it may represents an independent risk factor as proved in others tumour. PS-07-024 Granulomatous appendicitis: a diagnostic challenge. Clinico- pathological retrospective study of 60 cases A. Pasco Peña*, A. Larrea, G. Aísa Rivera, M.I. Cevallos, M. Mer- cado, Á. Panizo Santos *Hospital Universitario de Navarra, Spain Background & objectives: Granulomatous appendicitis (GA) is an uncommon finding of appendectomies. The causes can be classified as infections or noninfectious. There is also a group where a cause is never identified (idiopathic). In this study, we report the clinicopathological features of GA. Methods: We performed a single-centre, retrospective study of appendectomy specimens received by our department over a 26-year period of time (1995-2021). Clinical data were col- lected retrospectively from the medical records and the his- tological slides were reviewed. Additional stainings (Ziehl- Neelsen, Gram, PAS and Groccot) and molecular studies were performed. Results: We identified 60 GA cases: 32 men and 28 women. Ages ranged 1-83 years (median 33.5yrs). 44 cases had transmu- ral acute-subacute inflammation. Granulomas were found scat- tered throughout all layers of the wall: subserosa only (11.7%), submucosa+mucosa (65%) and transmural (23.3%). 12 GA were necrotizing granulomas. In 27 cases, granulomas were found in the lymphoid follicles with concomitant extrafollicular granulomas in 15. The presence of xanthogranulomatous inflammation was seen in 10 cases. Two cases were Ziehl-Neelsen positive and one case was PCR-TBC positive. The likely clinicopathological cause of GA: idiopathic (55%; 3 cases probably due to Yersinia), Crohn’s disease (21.7%), interval appendicitis (8.3%), tuberculosis (6.7%), foreign material (6.7%), and Actinomyces (1.7%). Conclusion: The incidence of GA was very low: only 60 cases in 26 years. Idiopathic (primary) granulomatous appendicitis is the leading cause of in our series, followed by Crohn’s disease. The site of occurrence in the appendix, the morphology of the granulomas and the clinical setting is often paramount in establishing the aetiology. In our series, special stains for infectious organisms in GA are of low diagnostic yield. PS-07-025 Impact of IL-17-positive lymphocytes and -197A/G SNP in development of gastric cancer E. Aleksandrova*, J. Ananiev, K. Ivanova, M. Hadzhi, M. Galabova *Trakia University, Bulgaria Background & objectives: An expanding body of evidence impli- cates the dualistic role of IL-17, a pro-inflammatory cytokine, in both pro- and anti-tumourigenic processes. Elevated IL-17 expres- sion has been observed in a variety of tumour tissues, including gastric cancer (GC). Methods: We investigated immunohistochemically 45 GC patients with antibodies against IL-17. Genotyping for the -197A/G SNP in the IL-17A gene was performed via PCR-RFLP method. The clinicopathological parameters and survival were analysed retrospectively. Results: We observed lower infiltration of IL-17-positive lympho- cytes (-PL) in the tumour border in patients with low differentiated gastric cancer (Chi-square test, p=0.052). Also, we found a ten- dency that patients without distant metastasis had lower infiltration in the tumour border with IL-17-PL (Chi-square test, p=0.106), but in the tumour we found that non-metastasis patients had signifi- cantly lower infiltration with IL-17-PC (Chi-square test, p=0.024). Our results showed that the carriers of the G-allele for the -197A/G SNP were in advanced clinical stage of the disease (Chi-square test, p=0.072). The G-allele was also associated with the histology type of the tumour- the G-allele carriers had intestinal type tumours (Chi-square test,p=0.105). Conclusion: Our results suggest that -197A/G SNP and IL-17-pos- itive lymphocytes could be helpful to outline the progression for patients with gastric cancer. Funding: This work was financially supported by the National Sci- ence Fund, Bulgarian, Research grant number KP-06-H23/2 from 17.12.2018 PS-07-026 Prognostic value of natural killer cells in colorectal carcinoma I. Helal*, K. Ben Abdallah, F. Khanchel, S. Fkih, R. Hedhli, E. Ben Brahim, R. Jouini, A. Chadli *Habib Thameur Hospital, Tunisia Background & objectives: Natural killer cells are considered to have prognostic impact in several solid tumours. In colorectal carcinoma, their role remains obscure. We aim to determine whether the presence of NK cells in tumour tissue is associated with a better overall survival. Methods: A total of 104 tumour specimens from patients after curative resection were reviewed. Areas with the highest lymphocyte density in the centre and margins of each specimen were marked. Tissue microarrays regrouping cores extracted from marked areas were formed. Immunohistochemistry was carried out on slides resulting from the section of TMA blocks. Anti-CD56 antibody was used for NK cells identification. Results: Mean age was 61.6 years. Gender ratio Male/Female was 1.36. 84.6% of tumours were Adenocarcinomas NOS, with a low differentiated grade in 80.7% of cases. 44.2% of patients were pTNM stage III or IV. Average follow-up period was 60 months. 41 deaths occurred. Mean number of NK cells in tumour centre and margins were 2.2 and 1.52 respectively. 31.7% of patients had a total of 4 NK cells or more. There was no significant difference in densities of NK cells between the centre and the margins of the tumour. Mean survival was 55.59 months. There was no correlation between density of NK cells in tumour tissue and overall survival (p=0.272). S97