THE DIAGNOSTIC EFFICACY OF CONTRAST ENHANCED-ENDOSCOPIC ULTRASONOGRAPHY IN DIFFERENTIAL DIAGNOSIS OF GASTRIC GASTROINTESTINAL STROMAL TUMOR (GIST) AND NON-GASTROINTESTINAL STROMAL TUMOR

Aims The aim of this study is to find specific features on CE-EUS in differential diagnosis of GIST with other SETs.

Methods We retrospectively reviewed the findings of CE-EUS of 25 hypoechoic tumors, located in gastric proper muscle layer in 25 patients The presence and degree of tumor vessel in the SET on CE-EUS was evaluated. The results were compared to histological diagnosis, in which obtained by EUS guided fine needle aspiration with biopsy or/and surgical resection.

Results 17 of 25 SETs were diagnosed as GIST by histological results. 6 SETs were diagnosed as leiomyoma and 2 SETs were schwannoma. In 14 of 17 GISTs tumor vessel was observed and In 8 non-GISTs tumor vessels were not observed. On statistical analysis, the presence of tumor vessel was significantly related to GIST (Odds ratio, 4.250; 95% confidential interval, 1.8–10.0; P < 0.001); 1 or 2 tumor vessels(1 +) in 5 cases, 2 or 3 tumor vessels (2 +) in 6 cases, more than 3 tumor vessels (3 +) in 3 cases and no tumor vessels in 3 cases. The sensitivity, specificity, accuracy and positive predictive value with vessel enhancement were about 100%, 66.7%, 77.4% and 84%. In 17 of GISTs hypoenhancement was observed in 5 cases, isoenhancement in 11 cases and hyperenhancement in 1 case. In 8 of non-GISTs, hypoenhancement was observed in 5 cases, isoinhancement in 2 cases, unenhancement in 1 case. The results showed that the tendency of correlation between iso-enhancement pattern and GISTs, but there was no statistical significance. (OR, 7.78 l; 95% CI 1.165–51.915; P = 0.061).

Conclusions The findings of tumor vessel enhancement in CE-EUS is useful for differential diagnosis between GIST and non-GIST in gastric hypoechoic tumor of proper muscle layer. The echo patterns of contrast enhancement were insufficiency for differential diagnosis between GIST and non-GIST.