Submucosal lifting agent ORISE gel causes extensive foreign body granuloma post endoscopic resection.

BACKGROUND: Submucosal injection of lifting solution is often performed to facilitate endoscopic mucosal resection or endoscopic submucosal dissection. ORISETM gel is a synthetic solution recently approved by the US Food and Drug Administration (FDA) in 2018 for use as submucosal lifting solution for endoscopic resection procedures and has gained popularity for its convenient pre-filled syringe. However, here the present two cases show that ORISETM gel induces marked foreign body giant cell granulomatous reaction in the submucosa and muscularis propria following endoscopic resection. METHODS AND RESULTS: A 73-year-old female underwent laparoscopic right colectomy after her initial endoscopic polypectomy of a hyperplastic polyp, and a 78-year-old male had partial gastrectomy following endoscopic mucosal resection of an invasive adenocarcinoma. Both patients had submucosal injection of ORISETM gel during endoscopic procedures, and the surgical resection specimens showed ORISETM gel deposition and extensive foreign body giant cell granulomatous reaction in the submucosa and muscularis propria. CONCLUSION: These cases raise the awareness that ORISETM gel stimulates extensive foreign body reaction at the injection site, and the further consequence is still unclear.