Endosonographic large-bore biopsy of gastric subepithelial tumors: a prospective multicenter study.

Background: Once gastric subepithelial lesions (SEL) are found, tissue diagnosis is required, considering the possible differential diagnosis of gastrointestinal stromal tumors (GIST). Previous studies have shown insufficient accuracy of endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA) using cytologic analysis.

Methods: The feasibility and yield of EUS-FNA-based histologic tissue acquisition for gastric SEL, using 19 G large-bore needles, was assessed in a 4-year multicenter, prospective study. All consecutive patients, who were referred for EUS-FNA for all SEL greater than 1 cm, were included.

Results: Of 100 patients with suspected gastric SEL, 71 lesions were found to be eligible. Endoscopic biopsies or resections or surgery were used alternatively for a variety of reasons in 25 patients. EUS-FNA using the 19 G needle was finally performed in 46/71 cases (65%) with one to four needle passes. Sufficient material for a definite or a suspected histological diagnosis was obtained in 52 and 7% of the cases, respectively. In 41%, the samples were not informative. Immunohistochemistry was possible in 91% of cases with sufficient amounts of tissue; 30% were GIST. Self-limited, mild hemorrhage occurred in 22%; one patient developed a fatal abscess.

Conclusion: Even when intended, EUS-guided 19 G FNA is only feasible in 46% of gastric SEL. The diagnostic yield of 19 G FNA was only 52%, but with excellent differentiation between GIST and leiomyoma. Infectious complications must be prevented.