Contrast-enhanced harmonic endoscopic ultrasonography for differential diagnosis of submucosal tumors of the upper gastrointestinal tract

Background and Aim: The study aims to evaluate contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) for the differential diagnosis of submucosal tumors (SMT) of the upper gastrointestinal tract. Methods: Between June 2008 and May 2015, 157 consecutive patients with submucosal lesions of the upper gastrointestinal tract were evaluated by CH-EUS. This was a single-center retrospective analysis of prospectively collected data in a registry. The data from 73 patients who later underwent surgical resection were analyzed in this study. Surgical specimens served as the final diagnoses. The two CH-EUS variables of blood flow (hyper-enhancement vs hypo-enhancement) and homogeneity of enhancement pattern were evaluated. Results: The final diagnoses were 58 gastrointestinal stromal tumors (GISTs) and 15 benign SMTs (two lipomas, five leiomyomas, five schwannomas, two glomus tumors, and one ectopic pancreas). On CH-EUS, 49 of 58 (84.5%) GISTs presented with hyper-enhancement, whereas 4 of 15 (26.7%) benign SMTs showed hyper-enhancement; 21 of 58 (36.2%) GISTs showed inhomogeneous contrast enhancement, while only 2 of 15 (13.3%) benign SMTs demonstrated inhomogeneous contrast enhancement. If hyper-enhancement was considered to indicate GISTs, the sensitivity, specificity, and accuracy were 84.5%, 73.3%, and 82.2%, respectively. If inhomogeneous enhancement was considered to indicate GISTs, the sensitivity, specificity, and accuracy were 36.2%, 86.7%, and 46.6%, respectively. In lesions of less than 2 cm, hyper-enhancement was a more sensitive indicator of GISTs than inhomogeneous enhancement. Conclusions: Hyper-enhancement and inhomogeneous enhancement were found to be a characteristic of GISTs. CH-EUS was useful for discrimination of benign SMTs from GISTs.