Which of the following would be the best morphological feature to distinguish ulcerative colitis from Crohn's disease?
Pseudopolyps are more commonly found in ulcerative colitis than Crohn's disease. These are discrete areas resulting from surviving islands of mucosa or heaped up granulation tissue. Since in ulcerative colitis there is diffuse mucosal inflammation these pseudopolyps are diffusely distributed. Distinguishing features between Ulcerative colitis and Crohn's disease: Ulcerative colitis Crohn's disease Rectal involvement Yes Variable Distribution Diffuse Segmental or diffuse Terminal ileum Backwash ileitis Thickened and stenosis Serosa Normal Creeping fat Mucosa Hemorrhagic Cobblestone and linear ulcers Pseudopolyps Frequent Less common Strictures No Common Fistulas No Common Lymphoid hyperplasia Infrequent Common Crypt abscess Extensive Focal Ref: Pediatric Inflammatory Bowel Disease By Petar Mamula page 227.
Diffuse distributions of pseudopolyps
Mucosal edema
Crypt abscesses
Lymphoid aggregates in the mucosa