You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is True about ulcerative colitis, all except and explain in detail?
Ulcerative colitis always involves the rectum and extends proximally in a continuous fashion to involve all or pa of the colon. Skip lesions are not seen. Disease of the entire colon is termed pancolitis. Isolated islands of regenerating mucosa often bulge into the lumen to create small elevations, termed pseudopolyps. Granulomas are not present. REF: ROBBINS BASIC PATHOLOGY, 9TH EDITION. PAGE 590. IMAGE REF: ROBBINS BASIC PATHOLOGY, 9TH EDITION, FIG.14-30, PAGE 591