A research article to be published on July 21, 2009 in the World Journal of Gastroenterology addresses this question. This research led by Professor Kim and his colleagues in Pusan National University, South Korea. They evaluated the EUS features of gastric GISTs in comparison with gastric leiomyomas, and tried to determine the EUS features that could predict the malignant potential of gastric GISTs according to the histological risk classification.
In their study, to differentiate GISTs from leiomyomas by EUS, the following four features were helpful; inhomogenicity, hyperechogenic spots, a marginal halo and higher echogenicity as compared with the surrounding muscle layer. These features appeared more frequently in GISTs than in leiomyomas. The presence of at least two of these four features had a sensitivity of 89.1% and a specificity of 85.7% for predicting GISTs.
Except for tumor size and irregularity of the border, most of the EUS features were not helpful in predicting the malignant potential of GISTs. On multivariate analysis, only the maximal diameter of the GISTs was an independent predictor. The optimal size for predicting malignant GISTs was 35 mm. The sensitivity and specificity using this value were 92.3% and 78.8%, respectively.Gastric mesenchymal tumors are often asymptomatic, and they are usually incidentally discovered during upper gastrointestinal endoscopy for unrelated conditions.