EUS-guided fine-needle biopsy (EUS-FNB) is a key modality for diagnosing pancreatic lesions, but its real-world accuracy may be influenced by sampling adequacy, tumor heterogeneity, and inconclusive histology. This study aimed to evaluate the diagnostic performance of EUS-FNB for (1) all pancreatic tumors and (2) specifically pancreatic adenocarcinoma, using final histopathology as the reference standard.

We retrospectively analyzed patients undergoing EUS-FNB for pancreatic lesions in a tertiary center. Based on procedural assessment, FNB results were categorized as tumoral or non-tumoral. Final histopathology classified lesions as pancreatic tumors (adenocarcinoma, pancreatic neuroendocrine tumors, ampullary/periampullary carcinoma, insulinoma), non-tumoral pancreatic disease, or indeterminate. Diagnostic accuracy was calculated for cases with conclusive histology; indeterminate outcomes were recorded to reflect sampling limitations.

Eighty-three patients had paired FNB and final histology results. Conclusive histopathology was available in 70/83 cases (60 pancreatic tumors, 10 non-tumoral lesions). For all pancreatic tumors, EUS-FNB demonstrated a sensitivity of 96.7%, specificity of 80.0%, and an overall accuracy of 94.3% (95% CI: 86.2%–97.8%), consistent with recent large-scale studies reporting comparable accuracy for pancreatic EUS-FNB [1,2].When restricting the target condition to pancreatic adenocarcinoma, FNB showed a sensitivity of 100%, specificity of 50%, and an overall accuracy of 72.3%. Histopathology was indeterminate in 13/83 patients (15.7%), reflecting insufficient or non-diagnostic tissue acquisition.

EUS-FNB demonstrated high diagnostic accuracy for pancreatic tumors, with results aligning with the upper range of contemporary evidence, in which accuracies of 85–95% are typically reported for solid pancreatic lesions [1–3]. The lower accuracy observed for pancreatic adenocarcinoma alone, despite excellent sensitivity, highlights the challenge of differentiating adenocarcinoma from other neoplastic entities when tissue sampling is limited. These findings reinforce the strong diagnostic utility of EUS-FNB while underscoring the importance of optimal sampling techniques and careful interpretation, particularly when precise tumor subtyping is clinically relevant.