Case Report
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World J Gastroenterol. Jul 14, 2013; 19(26): 4267-4270
Published online Jul 14, 2013. doi: 10.3748/wjg.v19.i26.4267
Unexpected endoscopic full-thickness resection of a duodenal neuroendocrine tumor
Ken Hatogai, Yasuhiro Oono, Kuang-I Fu, Tomoyuki Odagaki, Hiroaki Ikematsu, Takashi Kojima, Tomonori Yano, Kazuhiro Kaneko
Ken Hatogai, Yasuhiro Oono, Tomoyuki Odagaki, Hiroaki Ikematsu, Takashi Kojima, Tomonori Yano, Kazuhiro Kaneko, Division of Digestive Endoscopy, Department of Gastroenterology, National Cancer Center Hospital East, Kashiwa City, Chiba 277-8577, Japan
Kuang-I Fu, Department of Gastroenterology, Juntendou University Nerima Hospital, Tokyo 177-8521, Japan
Author contributions: Hatogai K drafted the manuscript under the direction of Oono Y; Fu KI revised the manuscript; Ikematsu H, Odagaki T and Kojima T contributed the case in endoscopic diagnosis; Yano T and Kaneko K made the final corrections and comments.
Correspondence to: Ken Hatogai, MD, Division of Digestive Endoscopy, Department of Gastroenterology, National Cancer Center Hospital East, 6-5-1, Kashiwanoha, Kashiwa City, Chiba, 277-8577, Japan. kn_hatogai@hotmail.com
Telephone: +81-4-71331111 Fax: +81-4-71319960
Received: February 1, 2013
Revised: April 3, 2013
Accepted: April 10, 2013
Published online: July 14, 2013
Processing time: 162 Days and 7.7 Hours
Abstract

A 57-year-old man underwent endoscopy for investigation of a duodenal polyp. Endoscopy revealed a hemispheric submucosal tumor, about 5 mm in diameter, in the anterior wall of the duodenal bulb. Endoscopic biopsy disclosed a neuroendocrine tumor histologically, therefore endoscopic mucosal resection was conducted. The tumor was effectively and evenly elevated after injection of a mixture of 0.2% hyaluronic acid and glycerol at a ratio of 1:1 into the submucosal layer. A small amount of indigo-carmine dye was also added for coloration of injection fluid. The lesion was completely resected en bloc with a snare after submucosal fluid injection. Immediately, muscle-fiber-like tissues were identified in the marginal area of the resected defect above the blue-colored layer, which suggested perforation. The defect was completely closed with a total of 9 endoclips, and no symptoms associated with peritonitis appeared thereafter. Histologically, the horizontal and vertical margins of the resected specimen were free of tumor and muscularis propria was also seen in the resected specimen. Generally, endoscopic mucosal resection is considered to be theoretically successful if the mucosal defect is colored blue. The blue layer in this case, however, had been created by unplanned injection into the subserosal rather than the submucosal layer.

Keywords: Endoscopic mucosal resection; Submucosal tumor; Neuroendocrine tumor; Hyaluronic acid; Perforation; Duodenum; Endoclip

Core tip: We herein report a case of endoscopic full-thickness resection of a duodenal neuroendocrine tumor after unplanned injection into the subserosal layer. Generally, large perforations require urgent salvage surgery and duodenal perforation is more serious than other sites of the gastrointestinal tract because of bile acid and pancreatic juice. In this case, we found the ‘‘mirror target sign’’ immediately, and repaired the defect endoscopically. Prompt recognition of this sign and rapid closing of the defect is important to minimize injury.