Comparison of histological analysis and endosonographic features in esophageal granular cell tumors

Background:  The increased use of esophagogastroduodenoscopy has revealed the esophagus to be a common site of occurrence of granular cell tumors (GCT). To clarify the endosonographic features of esophageal GCT, we compared endosonographic findings and histopathological analysis of resected specimens of esophageal GCT and submucosal leiomyomas. Methods:  We enrolled a total number of 18 consecutive patients with esophageal submucosal tumors. They were preoperatively examined using 15 MHz or 20 MHz probe endoscopic ultrasonography. The endosonographic findings were retrospectively compared with hisopathological findings of the resected specimens. Results:  Five GCT and 13 submucosal leiomyomas were diagnosed histologically as well as endosonographically. Pathological analysis revealed that the dispropotional mixture of tumor cells, fibrosis and muscularis mucosa within the GCT would be endosonographically visualized as a heterogeneous hypoechoic mass. Moreover, the laterally scattered tumor cells, together with adjacent thickened muscularis mucosa, are reflected by the unclear margin of the tumor by endoscopic ultrasonography. In contrast, in the submucosal leiomyomas, tumor cells and fibrosis were uniformly mixed and the margin of the tumor was clearly demarcated. These histological findings would be endosonographically recognized as a homogeneously hypoechoic mass with a clearly demarcated border. Conclusion:  A high-frequency probe endoscopic ultrasonography is useful for differentiating esophageal GCT from submucosal leiomyomas. Considering the histological characteristics, esophageal GCT should be resected with adequate tumor-free margin when endoscopic treatment is applied.