Efficacy and histologic frequencies of endoscopic ultrasonography-guided tissue acquisition using conventional fine-needle aspiration needles for gastric subepithelial hypoechoic mass.

ABSTRACT

Introduction/Purpose: For gastric subepithelial lesions (GSELs) showing a hypoechoic mass (HM) on endoscopic ultrasonography (EUS) imaging, the utility of EUS-guided tissue acquisition using conventional fine-needle aspiration needles (EUS-TA-CFNAN) and the frequency of histological types remain unclear. This study aimed to examine this issue. Methods: This prospective observational study enrolled 291 consecutive patients who underwent EUS-TA-CFNAN for GSELs showing an HM (GSELHM) on EUS imaging. Immunohistochemical analysis was performed for all EUS-TA-CFNAN and surgically resected specimens. The main outcome measures were the technical results of EUS-TA-CFNAN and the frequency of histological types in GSELHM. Results: The endoscopic ultrasound-guided tissue acquisition using conventional fine-needle aspiration needle diagnosis rate for GSELHM was 80.1% (95% confidence interval [CI] 75.0-84.5, 233/291). It was significantly lower for antrum (P = 0.004) and lesions smaller than 2 cm (P = 0.003). There were no adverse events. The immunohistochemical diagnoses of EUS-TA-CFNAN included 149 cases of gastrointestinal stromal tumour (GIST) (51.2%), 48 cases of leiomyoma (16.5%), 11 cases of schwannoma (3.8%), 8 cases of the ectopic pancreas (2.7%), 5 cases of subepithelial lesion like cancer (1.7%), 12 cases of other lesions (4.1%), and 58 cases of undiagnosable lesions (19.9%). The frequency of malignant or potentially malignant tumour in GSELHM was 55.0% (95% CI 49.1-60.8, 160/291). Surgery was performed in 149 patients according to the conclusive EUS-TA-CFNAN results, in which the diagnostic accuracy of EUS-TA-CFNAN was 97.3% (95% CI 94.7-99.9, 145/149). Conclusion: The use of EUS-TA-CFNAN for GSELHMs is safe and accurate. Gastric subepithelial lesions showing a hypoechoic mass have a reasonably high possibility of containing malignant or potentially malignant tumours, including GISTs.