Open biopsy guided by endoscopic ultrasonography from a gastric submucosal tumor growing outside the stomach.

Submucosal tunneling bloc biopsy for submucosal tumors growing inside the gastric wall is a safe and reliable method. However, it is difficult for an endoscopist to perform submucosal tunneling bloc biopsy and detect the demarcation line between the proper muscular layer and the capsule layer of submucosal tumors growing outside the gastric wall. A submucosal tumor in the lesser curvature of the stomach was identified in a 74-year-old man by esophagogastroduodenoscopy. Computed tomography revealed hetero-density with partial calcification of the tumor growing outside the gastric wall, that connected to approximately 10 mm of the muscular layer. Almost all of the tumor body was located outside the stomach. After the small connecting area was detected by endoscopic ultrasonography, two markings were placed at the opposite ends of the tumor. The tumor was removed via snare resection between the markings located immediately above the top of the tumor. After the biopsy site was reconfirmed using endoscopic ultrasonography, a large bloc biopsy was conducted. This new "open biopsy under endoscopic ultrasonography" is a simple, safe, and reliable method to obtain samples from any type of submucosal tumor growing inside or outside the stomach.