Pseudomembranous colitis

Endoscopic appearance of Clostridioides (formerly Clostridium) difficile-induced pseudomembranous colitis.
(Left panel) Scattered pseudomembranes are visible on top of the mucosa, being separated by areas of relatively normal mucosa. Some of the lesions have a red halo (arrows).
(Right panel) Yellow pseudomembrane circumferentially covering the entire colonic mucosa.

Endoscopic appearance of the normal sigmoid colonic mucosa. The fine vasculature is easily visible, and the surface is shiny and smooth. The folds are of normal thickness.