RT Journal Article SR Electronic T1 Unusual cause of colonic mucosal ulceration and gastrointestinal bleeding JF Frontline Gastroenterology JO Frontline Gastroenterol FD BMJ Publishing Group Ltd SP flgastro-2021-101844 DO 10.1136/flgastro-2021-101844 A1 Youseung Kim A1 Varun Kesar A1 David LeBel YR 2021 UL http://fg.bmj.com/content/early/2021/06/14/flgastro-2021-101844.abstract AB