68-year old male with watery diarrhoea and no endoscopic lesions.
Case Discussion
Collagenous colitis is a pattern of microscopic colitis: inflammation of the colon with no endoscopic findings. There are two main patterns of microscopic colitis: lymphocytic and collagenous. While both types show increased intra-epithelial lymphocytes (although fewer than seen in lymphocytic colitis) and mucin depletion, collagenous colitis is notable for patchy thickening of the sub-epithelial basement (10 microns or more, usually at least 15-20 micron-thick).
Image Contributors
Yoon, J., Hafezi-Bakhtiari, S.
Cite
Yoon, J., Hafezi-Bakhtiari, S. Colon, collagenous colitis. Digital Laboratory Medicine Library, Dept of Laboratory Medicine & Pathobiology, University of Toronto. Published
. Accessed December 17, 2025. https://dev.dlml.cflabs.ca/image/colon-collagenous-colitis-lmp30197
