Beyond microscopic colitis: a clinicopathologic evaluation of endoscopically apparent collagenous colitis, including...

Area of Science:

• Gastroenterology
• Pathology
• Endoscopy

Background:

• Collagenous colitis (CC) is characterized by chronic watery diarrhea and a thickened subepithelial collagen layer, typically with normal endoscopic findings.
• Endoscopically apparent variants of CC, including nodular patterns, are less commonly described.

Purpose of the Study:

• To describe endoscopically apparent variants of collagenous colitis, specifically nodular collagenous colitis (NCC).
• To analyze clinical, endoscopic, and histologic features of normal versus endoscopically apparent CC variants.

Main Methods:

• Retrospective review of 201 collagenous colitis (CC) cases.
• Classification of endoscopic findings into normal, subtle abnormalities, or nodular CC (NCC).
• Analysis of clinical features, medication exposures, and histology.

Main Results:

• Endoscopic abnormalities were observed in 12.9% of CC cases (16 subtle, 10 NCC).
• Clinical, histologic, and treatment features did not significantly differ between groups.
• Trends noted included increased Paneth cell metaplasia in apparent CC, higher prevalence of celiac disease and angiotensin receptor blocker use in NCC.

Conclusions:

• Endoscopically apparent CC, including NCC, can persist and may present with distinct associated conditions.
• The presence of endoscopic abnormalities should not preclude a diagnosis of CC if other features are consistent.
• Endoscopic findings like nodularity may persist even after clinical remission.