Patchiness of mucosal inflammation in treated ulcerative colitis: a prospective study

Area of Science:

• Gastroenterology
• Inflammatory Bowel Disease (IBD) research
• Colorectal pathology

Background:

• Ulcerative colitis (UC) is typically characterized by continuous colonic inflammation, often most severe in the rectum.
• Rectal sparing or patchy disease patterns have historically raised suspicion for Crohn's disease (CD).
• Previous observations suggest occasional rectal sparing and patchiness can occur in UC.

Purpose of the Study:

• To prospectively investigate the prevalence of patchiness, including rectal sparing, in patients with treated ulcerative colitis.
• To determine if these findings necessitate a change in diagnosis from UC to CD.

Main Methods:

• Prospective study of consecutive patients with longstanding ulcerative colitis.
• Left colon divided into three zones for scoring disease activity.
• Biopsy specimens graded for histologic activity by a blinded observer.
• Patchiness defined by endoscopic or histologic criteria, including rectal sparing.

Main Results:

• 17 out of 39 patients (44%) showed endoscopic evidence of patchiness, with 5 (13%) exhibiting rectal sparing.
• 13 out of 39 patients (33%) demonstrated histologic evidence of patchiness, including 6 (15%) with rectal sparing.
• 9 patients (23%) had both endoscopic and histologic evidence of patchiness; no difference in rectal therapy use was noted between patchy and non-patchy groups.

Conclusions:

• Patchy inflammation and rectal sparing are relatively common findings in treated ulcerative colitis.
• These patterns should not automatically prompt a diagnostic shift to Crohn's disease in patients with established UC.
• The study refines understanding of UC presentation, particularly in treated populations.