[Evaluation of upper gastrointestinal submucosal lesions by endoscopic ultrasonography]

Endoscopy is an established method for diagnosing gastrointestinal tract diseases, however, suspected subepithelial lesions usually cannot be appropriately evaluated by this technique alone. The prevalence of suspected submucosal gastric lesions at routine endoscopy has been estimated to 0.5%-1%. In this review, we evaluated the role of endoscopic ultrasonography (EUS) in the diagnosis of and management strategy for submucosal lesions. EUS has emerged as the most reliable investigative procedure of choice for evaluating submucosal tumors. EUS is the method of choice to differentiate between true intramural tumors and lesions caused by extraluminal compressions due to normal or pathologic structures. It can determine the originating layer(s) of intramural lesions; can differentiate echogenicity (anechoic, hypoechoic, hyperechoic, isoechoic), vascularity, size, shape, and border characteristics. Some endoscopic findings (color, consistency, mobility, 'pillow sign') can be helpful in narrowing the differential diagnosis. On the other hand, determination of the histologic layer and the internal echo patterns of some submucosal tumors are also predictive of benign or malignant tumors. EUS can provide an accurate diagnosis in 80% of patients with benign lesions and 64% of those with malignant lesions. Hypoechoic lesions in the 3rd and 4th layer are most prone to misclassification. If these cannot be differentiated exactly, EUS can serve as a guide on fine needle aspiration (FNA) biopsy or histologic core biopsies, providing samples for cytologic or histologic analysis. After that, the endoscopist can decide whether the lesion should be periodically followed up, or removed by endoscopy, endoscopic submucosal resection (EMR) or surgery.