Correlation between inflammation, vascularization, adipocyte percentage and exocrine cell percentage at the resection margin and the postoperative pancreatic fistula rate after distal pancreatectomy

Postoperative pancreatic fistula (POPF) remains the most common and impactful complication after distal (left) pancreatectomy (DP). While previous studies have identified histological features such as acinar cell content and fibrosis as risk factors for POPF after pancreatoduodenectomy (PD), their relevance in DP remains unclear. The aim of this study was to investigate whether histopathological features at the pancreatic transection margin are associated with clinically relevant POPF after DP. This retrospective pilot study included 51 patients who underwent DP between 2019 and 2022 at the Department of Surgery, Klinikum rechts der Isar, Technical University of Munich. Immunohistochemical staining of pancreatic resection (transection) margin tissue was performed for leukocytes (CD45), M1 macrophages (CD68), endothelial cells (CD31), exocrine cells (PanCK), and adipocytes. Quantitative analysis was conducted using the QuPath digital pathology platform, and associations between these histological features and clinically relevant POPF were assessed. CR-POPF occurred in 21 of 51 patients (41.2%). No significant differences were observed in the area fractions of CD45 (p = 0.139), CD68 (p = 0.318), CD31 (p = 0.476), PanCK (p = 0.656), or adipocyte content (p = 0.398) between the POPF and No POPF groups. Histological features at the pancreatic resection margin did not correlate with the development of POPF. Unlike in PD, histological composition of the pancreatic stump—specifically inflammation, vascularity, adipocyte content, and exocrine tissue—does not appear to predict POPF after DP. These findings suggest that technical, mechanical, and postoperative management factors may play a more dominant role in fistula formation in this context. Further prospective, multicenter studies are needed to validate these observations and guide risk stratification strategies.