Colonoscopy, mucosal biopsy and brush cytology in the assessment of patients with colorectal inflammatory bowel disease.

Patients with total long-standing mucosal ulcerative colitis are at an increased risk of developing carcinoma of the colon or rectum. Recently it has been suggested that cytological examination of the colon may play an important role in the examination of these patients. The present study was undertaken in order to determine the malignancy/severe dysplasia rate in our patients and to examine the role of cytology in comparison with mucosal biopsy in the detection of mucosal abnormality. Three patients had severe dysplasia in the absence of active inflammation (7.1%). Fifty-four patients were examined concurrently by histology and cytological brushing and at least seven specimens were obtained from each patient. Cytological examination detected active mucosal inflammation more often than histological examination at all sites in the colon. There was good agreement between the cytologists' evaluation, routine histopathological examination and endoscopic evaluation of the colorectal mucosa, although the latter tended to underestimate the degree of active inflammation. It was concluded that, since there was no real improvement in sampling by brush cytology, there may be little advantage in supplementing routine biopsy with brush cytology in patients with long-standing inflammatory bowel disease.