INTESTINE - Crohn's disease

This consists of terminal ileum, caecum, ascending colon and appendix. The distal portion of the terminal ileum shows marked thickening of the wall, which begins abruptly and ends apparently equally abruptly in the region of the ileo-caecal valve. The thickening of the wall is annular and is obviously narrowing the lumen. Linear ulcers are not obvious in this specimen. A loop of ileum, uninvolved, is adherent to the mesentery.
This man presented with a vesico-colic fistula, with a previous history of abdominal pain for some two years. He had had diarrhoea and one episode of bright rectal bleeding. The histology of the lesions is that of Crohn's disease.