Optimal Puncture Number and Tissue Evaluation Method in Endoscopic Ultrasound-Guided Fine-Needle Biopsy for Patients with Malignant Neoplasm of Pancreas.

Background/Objectives: Endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) has become the standard for diagnosing solid pancreatic masses (SPMs). However, in the absence of rapid on-site cytopathologic evaluation (ROSE), the optimal number of needle passes remains uncertain. This study aimed to evaluate the diagnostic performance of EUS-FNB using a gross-eyed evaluation with the fanning technique in patients with pancreatic malignancy. Methods: This retrospective single-center study included 140 patients with confirmed pancreatic malignancy who underwent EUS-FNB with at least three needle passes between January 2022 and December 2025. Gross-eyed visual inspection for whitish core tissue was used to assess the specimen adequacy. The primary outcome was the diagnostic rate of malignancy. The secondary outcomes included the tissue adequacy and yield rate of malignancy. Results: The diagnostic rate of malignancy improved with additional passes, 72.1% for one pass, 82.9% for two, and 90.7% for three. However, the gain beyond two passes was marginal. The tissue adequacy was high across all passes (≥94.3%), with most samples deemed adequate within two passes. The yield rate of malignancy similarly improved from 82.1% (one pass) to 91.4% (three passes). No adverse events were reported. Gross-eyed evaluation was feasible in all cases and guided effective sampling. Conclusions: EUS-FNB with two puncture numbers and the fanning technique achieves high diagnostic performance for pancreatic malignancy without the need for ROSE and MOSE. Two passes appear sufficient in most cases, supporting a simplified and safe approach that minimizes unnecessary needle passes.