Endoscopic ultrasonographic characteristics of gastric schwannoma distinguished from gastrointestinal stromal tumor.

ABSTRACT

BACKGROUND/AIMS: Gastric schwannoma (GS), a rare neurogenic mesenchymal tumor, is usually benign, slow-growing, and asymptomatic. However, GS is often misdiagnosed as gastrointestinal stromal tumors (GIST) on endoscopic and radiological examinations. The purpose of this study was to evaluate EUS characteristics of GS distinguished from GIST. METHODS: A total of 119 gastric subepithelial lesions, including 31 GSs and 88 GISTs, who were histologically identified and underwent EUS, were enrolled in this study. We evaluated the EUS characteristics, including location, size, gross morphology, mucosal lesion, layer of origin, border, echogenic pattern, marginal halo, and presence of an internal echoic lesion by retrospective review of the medical records. RESULTS: GS patients comprised nine males and 22 females, indicating female predominance. In the gross morphology according to Yamada's classification, type I was predominant in GS and type III was predominant in GIST. In location, GSs were predominantly located in the gastric body and GISTs were predominantly located in the cardia or fundus. The frequency of 4th layer origin and isoechogenicity as compared to the echogenicity of proper muscle layer was significantly more common in GS than GIST. Although not statistically significant, marginal halo was more frequent in GS than GIST. The presence of an internal echoic lesion was significantly more common in GIST than GS. CONCLUSIONS: The EUS characteristics, including tumor location, gross morphology, layer of origin, echogenicity in comparison with the normal muscle layer, and presence of an internal echoic lesion may be useful in distinguishing between GS and GIST.