Randomized crossover trial comparing EUS‐guided fine‐needle aspiration with EUS‐guided fine‐needle biopsy for gastric subepithelial tumors

Aim The purpose of this study is to compare the diagnostic yield of endoscopic ultrasound (EUS)‐guided fine‐needle aspiration (EUS‐FNA) and EUS‐guided fine‐needle biopsy (EUS‐FNB) for gastric subepithelial tumors (SET). Methods Patients diagnosed SET derived from fourth layer of the stomach were prospectively enrolled and randomly assigned to undergo both EUS‐FNA using standard needle and EUS‐FNB using a core biopsy needle alternatively to the same lesion a total of four times per session. The specimen was carefully examined for the presence of a macroscopic visible core, appearing as threadlike yellowish or bloody pieces of tissue and blinded histocytologic analyses were conducted. For spindle cell lesions by hematoxylin and eosin staining (H&E) on histologic evaluation, immunohistochemical staining was performed in all cases to confirm the pathological diagnosis. Results A total of 23 patients were enrolled and underwent paired EUS‐FNA and ‐FNB sampling. The diagnostic rate due to immunohistochemical staining was 73.9% and 91.3%, respectively (P = .120). The rate of obtaining specimens with a macroscopic yellowish core and only a bloody core among the tissue specimens were respectively 43.5% and 52.2% for EUS‐FNA and 69.6% and 30.4% for EUS‐FNB. The diagnostic rate for a yellowish core (84.6%) and a bloody core (84.2%, P = .971) did not differ significantly. Conclusion Both techniques were equivalently safe and successful in terms of a high diagnostic yield for gastric SET. And the tissue that can be immunohistochemically stained is present even in the specimens that appear to be a macroscopically bloody core.