Axonal degeneration/necrosis: a possible ultrastructural marker for Crohn's disease.

Axonal degeneration/necrosis has previously been demonstrated in the small bowel autonomic nerve plexus of patients with Crohn's disease. It was suggested that this feature might be helpful in the differential diagnosis of Crohn's disease from other conditions, specifically ulcerative colitis. We performed a blind prospective study and examined tissue from 34 colonic specimens, in 15 patients, by electron microscopy. Cases of Crohn's disease (3 cases), ulcerative colitis (5 cases), and other controls [adenocarcinoma (4 cases), familial polyposis (1 case), peritonitis (1 case), and radiation colitis (1 case)] were evaluated for inflammation and axonal changes. It was found that only the cases of Crohn's disease showed extensive, seemingly independent, severe axonal changes that were unassociated with other markers of inflammation. This feature may be useful in the differential diagnosis between Crohn's disease and ulcerative colitis.