Gastrointestinal stromal tumors of the stomach: Endosonographic differentiation in relation to histological risk

Background and Aim: The aim of this study was to determine the endosonographic characteristics of gastrointestinal stromal tumors (GISTs) of the stomach according to histological risk classification. Methods: Twenty-four cases of histologically proven c-kit positive GISTs were divided into three groups according to histological risk: low risk (n = 14), intermediate risk (n = 7) and high risk (n = 3). Endoscopic ultrasonography (EUS) features recorded were: size, ulceration, regularity of marginal border, lobulation, shape of tumor, marginal halo, homogeneity, internal echogenic or cystic foci, and the presence of exophytic development. Results: Significant differences were seen in size between the groups studied (P = 0.026). All tumors in the high risk group had mucosal ulceration, which was more commonly seen in the intermediate risk group compared to the low risk group (P = 0.014). All tumors in the high risk group had irregular borders, but only three cases out of 11 in the low risk group had irregular borders (P = 0.039). Thirteen cases in the low risk group and five cases in the intermediate risk group had an oval or round shape; however, only one case in the high risk group showed this (P = 0.043). The optimal size value for prediction of the intermediate and high risk group was 30 mm. Sensitivity and specificity with this value was 80% and 79%, respectively. Conclusion: Large, especially larger than 30 mm, GISTs of the stomach with irregular borders, mucosal ulceration and a non-oval shape on EUS suggest higher risk GISTs of the stomach. These criteria might aid in the clinical management of GISTs of the stomach.