Ulcerative Colitis • Chronic relapsing ulcero-inflammatory disease, most common Inflammatory Bowel Disease (IBD) • Location; Rectum, does not involve other areas if GIT • Gross features; - Pseudopolyps - Areas of friable, bloody residual mucosa - Hemorrhage - Extensive broad-based ulceration - Backwash ileitis - No skip lesions • Microscopy - Inflammation limited to mucosa and submucosa - No granulomas seen - Crypt abscesses containing neutrophils - Dysplasia • Radiography; Lead pipe appearance due to loss of haustrations Crohn’s Disease • Chronic granulomatous ulcero-constrictive disease • Location; Terminal ileum, involves GIT from mouth to anus • Gross features; - Aphthous ulcer - Thick bowel and narrow lumen - Fissures, strictures and fistula - Serpentine linear ulceration - Creeping fat - Skip lesions - Cobblestone appearance • Microscopy - Transmural inflammation - Non-caseating granuloma - Lymphoid aggregates - Dyplasia less likely • Radiography; String sign in terminal ileum due to narrowing of lumen