In performing colonoscopy over a 4-yr period on 112 patients with long-standing
ulcerative colitis, a dysplasia-associated lesion or mass (
DALM) was found in 12. This appeared as either a single polypoid mass (5 cases), a plaquelike lesion (2 cases), or multiple
polyps (5 cases). In 7 of these 12 cases
carcinoma was subsequently found. This was particularly true in the 5 cases of single polypoid masses where all 5 contained invasive
carcinoma. In none of the cases associated with
malignancy did multiple biopsies of the
DALM reveal invasive
carcinoma. In only 2 of the 7 patients with
carcinoma was the dysplasia "severe," being "mild" or "moderate" in the remaining 5. In the 27 patients with dysplasia found incidentally in random biopsies of flat mucosa only one
carcinoma was found, in contrast to the 7
cancers in 12 patients with
DALM. This difference leads us to regard the finding of
DALM, especially a single polypoid mass, as highly significant in patients with long-standing
ulcerative colitis. It carries a sufficiently high risk of
cancer, thereby constituting a strong indication for
colectomy.