Fascin is overexpressed in inflammatory bowel disease and in colonic epithelium actively undergoing restitution and regeneration. Fascin immunoreactivity was detected in specimens of human colorectal mucosa by immunoperoxidase staining. A: Diverticulitis resection margin showing positive staining in the crypt base - 200 × magnification. B: Ulcerative colitis showing positive staining in the base of the elongated crypts - 100 ×. C: Crohn's colitis showing strong positive staining toward the base of the elongated crypts - 100 ×. D: Crohn's colitis showing patchy fascin immunoreactivity throughout the gland - 200 ×. E: Ulcerative colitis with low-grade dysplasia showing strong and widespread fascin expression - 100 ×. F: Ulcerative colitis with high-grade dysplasia showing strong and widespread fascin expression - 200 ×. G: Ulcerative colitis showing fascin staining in the flattened epithelial cells undertaking restitution - 200 ×. H: enlargement of an area of panel G illustrating the fascin-positive epithelial cells (arrowheads). I: fascin positive epithelial cells undertaking restitution in a sample of Crohn's colitis. J: A regenerative polyp in a sample of ulcerative colitis showing fascin positivity in the newly forming crypts - 200 ×. K & L: Fascin expression in branching crypts (arrowheads) in regenerating ulcerative colitis tissue - 200 ×.