To increase the diagnostic accuracy of subepithelial tumors, larger tissue samples are required. It is difficult to obtain adequate tissue samples. There were several biopsy methods to obtain tissue samples. Pathological examination would include mitosis counts, particularly in hypoechoic subepithelial tumors located in the 4th layer of the gastric wall, where differentiation between leiomyoma of benign nature and gastrointestinal stromal tumor (GIST) of malignant potential is essential.

So We hypothesize that unroofing biopsy is an more appropriate method than EUS-FNB(endoscopic ultrasonography guided fine needle biopsy). We will compare diagnostic accuracy and complications between EUS-FNB & unroofing biopsy.

Inclusion Criteria:

• Older than 19 years old and younger than 80 years old
• Suspected upper gastrointestinal subepithelial tumors(≥15mm, ≤35mm) that were originated from muscularis propria layer on endoscopic ultrasonography(EUS)

Exclusion Criteria:

• Patient who had bleeding tendency
• Any previous surgery on esophagus, stomach or duodenum
• Patients who can not be underwent sedated endoscopy
• Gastrointestinal subepithelial tumor that was not origianted from muscularis propria layer on EUS
• Constrast related allergic disease