What does it mean when sigmoidoscopy report says mucosa mild patchy erythema found in area extending from the rectum to distal sigmoid. large fistula 1cm from anal verge at 6o'clock.opening 3-4mm?

Changes: Described on report are consistent with inflammation (patchy erythema) and a vicious tunneled communication (fistula) between the colon and skin and/or bowel loops, for example. Such changes are typically seen in inflammatory bowel disease, but other causes cannot be ruled out. Your main reference should be your gastroenterologist who would be best positioned to discuss findings in proper context.