Endoscopic ultrasound without tissue acquisition has poor accuracy for diagnosing gastric subepithelial tumors

Abstract

Incidental gastric subepithelial tumor (SET) is frequently found during endoscopy. Although endoscopic ultrasonography (EUS) can provide useful information, its diagnostic accuracy varies. Most of the potentially malignant tumors observed on EUS are hypoechoic lesions. Therefore, we aimed to investigate the diagnostic accuracy of EUS for hypoechoic lesions located in the submucosa or proper muscle layer. We also evaluated various characteristics for potential associations with diagnostic accuracy.A retrospective review was conducted of the medical records of 99 patients who were diagnosed with gastric SET and who underwent EUS with pathologic confirmation between March 2008 and April 2015. After reviewing the endoscopic and pathologic findings, we attempted to analyze factors that were associated with the diagnostic accuracy of EUS.The mean ± standard deviation size of the lesions was 20.0 ± 12.7 mm. The most common location was the upper third of the stomach (43.4%). The overall accuracy of EUS was 66.7%. No statistically significant difference in EUS accuracy was observed according to the location, size, or layer of the lesion. The following pathologic diagnostic methods were used: EUS-guided fine needle aspiration (3.0%), forceps biopsy (16.2%), deep tissue biopsy using cap-assisted mucosal resection (8.1%), endoscopic submucosal dissection (25.2%), and operation (47.5%). The accuracy of EUS according to the expected diagnosis of the lesion was 77.1% for gastrointestinal stromal tumor, 50% for neuroendocrine tumor, and 50% for ectopic pancreas.Although EUS is a useful tool for gastric SET in clinical practice, the accuracy of diagnostic EUS is suboptimal. When considering whether to treat gastric SET, the decision should be made based on the pathologic diagnosis.

Conflict of interest statement

The authors have no conflicts of interest to disclose.

Figures

Figure 1

Flow diagram showing the study design and population.

Figure 2

A lesion showing the histology of follicular lymphoma after endoscopic submucosal dissection (ESD). (A) Upper endoscopy showed a well defined, polypoid gastric subepithelial lesion with a size of about 1.5 cm in the middle body, anterior wall. This lesion had a central mucosal erythema that is believed to be a scar created by a previous biopsy that was performed at another medical center. (B) On endoscopic ultrasonography, the lesion appeared as a 15 mm × 5 mm hypoechoic mass in the submucosa layer without infiltration of the muscularis propria. It was presumed to be a neuroendocrine tumor, even though the lesion had inhomogeneous and multiseptated morphological features. (C) The ESD specimen of this lesion appeared to be 2.8 × 2.4 × 0.6 cm3 in size after ESD, which had been performed without complications. (D) Histopathological analysis of the ESD specimen showed lymphoid hyperplasia below the normal gastric mucosa (hematoxylin and eosin stain, original magnification ×12). (E) This structure showed back-to-back arrangement and a very thin mantle zone (hematoxylin and eosin, original magnification ×200). (F) Lymphocytes of the abnormal structure were positive for CD20; this finding was compatible with follicular lymphoma (hematoxylin and eosin, original magnification ×200).

Figure 3

A lesion showing the histology of ectopic pancreas after endoscopic strip biopsy. (A) Upper endoscopy showed a gastric subepithelial lesion in the lesser curvature of the lower body. The lesion had an irregular margin and surface. (B) On endoscopic ultrasonography, it appeared as a well defined hypoechoic mass, mainly in the muscularis propria. The lesion was therefore presumed to be a gastrointestinal stromal tumor, even though it had heterogeneous echotexture. (C) The specimen from the endoscopic strip biopsy had a yellowish inner portion, which was presumed to be pancreatic tissue. (D) Histopathological analysis of the biopsy specimen showed the lesion in the muscularis propria layer with intact overlying mucosa and submucosa (hematoxylin and eosin, original magnification ×15) (yellow arrow). (E) Viewed at greater magnification, the specimen showed the presence of pancreatic acini and ductal structures. The features were compatible with ectopic pancreas (hematoxylin and eosin, original magnification ×400).