Predicting malignant potential of gastrointestinal stromal tumors using endoscopic ultrasound

Background The aim of this study was to determine which EUS characteristics correlate with malignant potential of GISTs. Methods All patients with a diagnosis of GIST based on surgical resection and preoperative EUS at our institution from January 2000 to July 2006 were identified. Pathology reports were used to determine NIH classification of each GIST and EUS exams were reviewed. EUS features were compared to NIH classification of very low/low risk malignant potential or intermediate/high risk malignant potential. Results Fourteen patients had lesions of very low or low risk malignant potential, and 12 patients had lesions of intermediate or high-risk malignant potential. EUS features of tumor size (P = 0.002), irregular extraluminal border (P = 0.005), local invasion (P = 0.02), and heterogeneity (P = 0.02) were statistically significant correlates of intermediate or high risk malignant potential. Conclusions EUS characteristics of tumor size, extraluminal border, depth, and heterogeneity can be used to predict malignant potential of GISTs.