Scanning electron-microscopic lesions in Crohn's disease: relevance for the interpretation of postoperative...

Endoscopic postoperative recurrence often occurs a few months after surgical therapy for Crohn's disease, even if the resection margins were macroscopically free of disease. Why the disease primarily recurs at the anastomotic site is not known. This study investigated resection margins in Crohn's disease in an attempt to clarify whether early lesions are relevant to the interpretation of postoperative recurrence.

Specimens of surgically resected bowel from 29 patients with Crohn's disease and tissue from 11 controls were studied with a scanning electron microscope.

In Crohn's disease, a triad of early lesions occurring in both histopathologically unaffected and affected mucosa was revealed; the triad consisted of mucosal architectural alterations, epithelial bridge formation, and goblet-cell hyperplasia or hypertrophy or both. Seventy-three percent of patients showed early alterations within histopathologically unaffected margins in the small bowel, and 71% had such alterations in the large bowel.

The findings provide further evidence for the concept of diffuse involvement of the whole gastrointestinal tract by the disease process. The endoscopic recurrence rate in the first year after the operative procedure is almost identical to the number of early lesions present during surgery. The term "postoperatively recurrent disease" should be used only if relevant clinical parameters change.