[Viewpoint] Ulcerative colitis: moving beyond the mucosal dogma

Ulcerative colitis has traditionally been regarded as a non-fibrotic, solely mucosal disease, whereas Crohn's disease is characterised by transmural inflammation and fibrosis. However, more recent evidence supports the existence of disease involvement beyond the mucosa in ulcerative colitis. Intestinal ultrasound has allowed for dynamic, in-vivo characterisation of the transmural alterations that occur in ulcerative colitis, such as increased bowel wall thickness, submucosal thickening, loss of bowel wall stratification, haustral loss, and mesenteric fibrofatty proliferation.