Differential diagnosis of adenomas and dysplastic lesions in patients with ulcerative colitis.

In a retrospective study, unequivocal neoplastic lesions (126 circumscribed lesions, 10 large-area lesions) in 76 patients with known ulcerative colitis were classified into adenomas and dysplastic lesions on the basis of pathomorphological criteria. The macroscopic appearance, gland architecture, mucin vacuoles, the appearance of the nucleus, the stroma/gland ratio, the position of the proliferation zone, the interface between the lesion and the surrounding mucosa, and the state of neighbouring mucosa were all assessed. In 31 patients (41%), the lesions were classified as adenomas, in 42 patients (55%) as dysplastic lesions. A further three patients (4%) were found to have both adenomas and dysplastic lesions. The average age of the patients with adenomas was 66.0 years, that of those with dysplastic lesions 43.4 years. The mean duration of the disease in patients with adenomas was 7.2 years, and in patients with dysplastic lesions 12.6 years. Among the patients with adenomas, 65% has solitary and 35% multiple lesions; among the patients with dysplastic lesions, the corresponding figures were 27% and 73%. No significant differences were found in sex distribution, the extent of the ulcerative colitis or the site of the lesions. Successful differentiation between adenomas and dysplastic lesions in ulcerative colitis patients requires a differentiated therapeutic response.