Value of mucin histochemistry in follow up surveillance of patients with long standing ulcerative colitis.

It has been suggested that diffuse changes in epithelial mucins may help to identify a subgroup of patients with ulcerative colitis who are at increased risk of developing colorectal cancer. Colonoscopic biopsy specimens were taken from 11 colitic patients shortly before colectomies were performed, in which cancer was identified. These patients were matched to colitic patients without cancer for age, sex, and duration of disease. Sections were stained with high iron diamine and alcian blue (HID-AB), mild periodic acid Schiff, and for peanut lectin binding sugar sequences. The sections were assessed blindly and graded semiquantitatively. Most showed ulcerative colitis in remission or mild active disease. There were no differences between the study and control groups. Metaplastic foci were more common in the group who had cancer. These showed increased staining of mucus by mild periodic acid Schiff and increased binding by peanut lectin to the supranuclear (Golgi) zone. Epithelial dysplasia (detected in four of the patients with cancer showed focal intense binding by peanut lectin to cytoplasm, mucus, and glycocalyx. Although dysplasia differed histochemically from normal tissue, special techniques did not facilitate its diagnosis.