Correlation between endoscopic resection outcomes and endosonographic findings in gastric tumors with muscularis propria origin

Abstract

Endoscopic resection is an effective treatment for subepithelial tumors arising from the muscularis propria layer of the stomach. However, the invasion pattern revealed by the pathological examination of tumor specimens is often not consistent with the findings of preprocedural endoscopic ultrasounds (EUS). We compared the real growing patterns of tumors, as evaluated on histopathological examination, with their EUS images, and analyzed the outcomes of endoscopic resections in relation to the EUS findings. From January 2006 to June 2015, 32 patients underwent endoscopic resection for gastric tumors originating from the muscularis propria at our hospital. We divided the patients into 3 groups according to the location of the tumor as diagnosed using pre procedural EUS: submucosa (group I, n = 5), muscularis propria (group II, n = 14), and tumors extending into the outer cavity (group III, n = 13). Histopathological examination revealed 15 patients with gastrointestinal stromal tumors (GISTs), 14 with leiomyomas, and 3 with schwannomas. Accuracy of EUS in evaluating tumor invasion was 56%. Some tumors in groups I and II was removed by endoscopic submucosal dissection only. Muscular dissection was needed in 10 patients (71%) in group II and 9 patients (69%) in group III. Four patients (31%) in group III were found to have subserosal tumors. The complete resection rate was 88% (23 patients) among patients who underwent endoscopic submucosal dissection and endoscopic muscular dissection, and 67% (4 patients) among patients who underwent endoscopic subserosal dissection (ESSD). The tumor was completely removed in 12 patients (86%) in group II and 10 patients (77%) in group III. EUS accurately predicts the layer of the subepithelial tumor in the stomach; however, the pattern of invasion of surrounding structures is difficult to evaluate using EUS.