Lead pipe appearance of colon is a classical finding in chronic ulcerative colitis. It is found on plain radiography, CT scan, and MRI. Longstanding ulcerative colitis causes hypertrophy of muscularis layer of the large intestine. Consequently, the colon acquires lead-pipe appearance. Reference: https://radiopaedia.org/articles/lead-pipe-sign-colon Image via: https://radiopaedia.org/cases/lead-pipe-bowel