Cryptitis The pathology in ulcerative colitis typically involves distoion of crypt architecture, inflammation of crypts (cryptitis), frank crypt abscess, and hemorrhage or inflammatory cells in the lamina propria. Pathology of ulcerative colitis. Macroscopic features Ulcerative colitis is a mucosal disease that usually involves the rectum and extends proximally to involve all or pa of the colon. The lesion is continuous and normal areas between the lesions (skip lesions) do not occur. With mild inflammation the mucosa is erythematous and has a fine granular surface that appears like sand paper. In severe cases mucosa is hemorrhagic. ulcerated and edematous. In long standing cases. inflammatory polyps (pseudopolyp) may be present as a result of epithelial regeneration. With many years of disease the mucosa becomes atrophic and featureless and entire colon becomes narrowed and shoened. Microscopic features :? The impoant pathological characteristic is that the process is limited to the mucosa and superficial submucosa with deeper layers unaffected except in fulminant disease. Two major features in ulcerative colitis suggests chronicity Distoion of the crypt architecture of the colon (cryptitits) - Crypts may be bifid and reduced in number often with a gap between crypt bases and musculoris mucosae. Diffuse predominantly mononuclear infiltrate in lanzina propria is universally present - Neutrophilic infiltration of epithelial layer produce collection of neutrophils in crypt (crypt abscess).