Abstract
INTRODUCTION: Extra-gastrointestinal stromal tumors (EGISTs) are non-gastrointestinal sarcomas originating from Cajal-like cells. Recent studies show the tumor microenvironment is crucial and highlight the importance of intra-tumoral leukocyte populations in malignancies, which are greatly impacting treatment strategies in EGISTs. AIM AND OBJECTIVES: This study aims to characterize intra-tumoral leukocyte populations in EGISTs, correlating proliferative index (ki67) with leukocyte density and examining age-related effects on proliferative activity and immune response. METHODS: We conducted a retrospective analysis on 25 patients with EGIST who came at "Victor Babes" National Institute of Pathology and Bucharest University Emergency Hospital between January 2007 and June 2020. After excluding five patients, a total of 19 subjects were included in the present study. Immunohistochemistry utilizing CD5, CD20, CD45 and ki67 antibodies identified and assessed intratumoral lymphocytes, analyzed via QuPath software. Statistical analyses included Pearson correlation, Kruskal-Wallis tests and Bonferroni corrections. RESULTS: The mean age of patients diagnosed with EGIST was 51 years; ki67 expression varied among morphological types. Immunohistochemistry revealed distinct tumor-infiltrating lymphocytes (TIL) densities with significant associations between ki67 and TIL-CD05/CD20 positive cells. Age-related correlations were noted, which highlighted complexities within the tumor microenvironment. CONCLUSION: Our findings emphasize the role of the immune microenvironment in EGISTs, showing significant correlations between ki67 expression and TIL densities as well as age-related associations. This study enhances our understanding of EGIST pathophysiology, urging further exploration for improved therapeutic approaches and comprehensive insights into immune responses in EGISTs.