Radiological detection of colonic dysplasia (precarcinoma) in chronic ulcerative colitis.

Epithelial dysplasia occurring in long-standing ulcerative colitis is a precancerous lesion. Macroscopically it has a nodular or villous appearance or may be indistinguishable from the surrounding mucosa. An investigation into the radiological diagnosis of dysplasia, using in vivo and in vitro double-contrast examinations with magnification radiographic studies, correlated with the histological analysis, has been made in four patients. Characteristic radiological abnormalities have been identified in the areas of the mucosa associated with histologically proven dysplasia. These appearances include nodularity and irregular areas with sharply angulated edges which may represent enlarged areae colonicae. The demonstration of these changes is an indication for endoscopic examination and biopsy of the suspicious area.