What is true about ulcerative colitis

Classically, ulcerative colitis begins in the rectum, and in continuity extends upwards into the sigmoid colon, descending colon, transverse colon, and sometimes may involve the entire colon. The colonic contents may rarely backflow into the terminal ileum in continuity, causing 'back-wash ileitis' in about 10% of cases. Grossly, the characteristic feature is the continuous involvement of the rectum and colon without any uninvolved skip areas compared to Crohn's disease. TEXTBOOK OF PATHOLOGY 6TH EDITION HARSH MOHAN PAGE NO:567,568 IMAGE REF: GENERAL AND SYSTEMIC PATHOLOGY RAMDAS 2ND EDITION, PAGE 509