EUS-FNA/B represents a key diagnostic modality for the evaluation of gastric subepithelial lesions, which are often incidentally identified and comprise a heterogeneous group of pathologies. However, the diagnostic performance of EUS-FNA/B is affected by lesion-specific features, procedural factors, and operator expertise. This study aimed to identify the factors associated with the diagnostic yield of EUS-FNA/B in two tertiary centers in Greece.

Data from consecutive patients with gastric subepithelial lesions who underwent EUS-FNA/B between 2017 and 2025 were retrospectively collected. Variables collected included patient demographics, needle type and diameter, number of needle passes, lesion size, and final cytological diagnosis. Associations between lesion size, needle characteristics, number of passes, and diagnostic cytology were assessed.

A total of 118 EUS-FNA/B were performed in 118 consecutive patients, 56 (47%) males and 63 (53%) females, with a median age of 67,5 years (range: 29–90). Cytology was diagnostic in 100 cases (85%) and non-diagnostic in 18 cases (15%). Of the diagnostic samples, 88 (88%) were reported as neoplastic while 11(11%) were non-neoplastic. In the neoplastic category, the predominant diagnosis was of gastrointestinal stromal tumor (53,4%), followed by leiomyoma (39,7%). In the non-neoplastic category, the most common diagnosis was pancreatic rest (18%). Lesion size >19 mm (OR = 0.29, 95% CI: 0.12–0.72, p = 0.007), ≥2 needle passes (OR = 5.99, 95% CI: 2.20–16.3, p < 0.001) and use of EUS-FNB needle  (OR = 4.21, 95% CI: 1.57–11.3, p = 0.004) were associated with a higher diagnostic yield.

The results of our study suggest that performing two or more needle passes, targeting lesions >19 mm, and the use of EUS-FNB needles were independently associated with a significantly higher diagnostic yield in the evaluation of gastric subepithelial lesions.