Rectal biopsy as a prognostic guide in Crohn's colitis.

In a retrospective study, 64 rectal biopsies from 27 patients with Crohn's disease limited to the large bowel have been reviewed using a semiquantitative grading of histological abnormality. The subsequent clinical course was assessed independently, and patients were included in one of four categories: (1) remaining asymptomatic; (2) showing continued moderate inflammatory activity; (3) requiring colectomy; and (4) dying as a direct result of colonic disease. Biopsies from group (4) showed a greater degree of histological abnormality than those in the other three groups. This difference was statistically significant for first biopsies ((4)-(1) p less than 0-05; (4)-(2) p less than 0-05). In any one patient the histological appearances were relatively constant from one biopsy to the next. The presence of either fissuring or ulceration suggested a poor prognosis.