Clinicopathological features of serrated adenoma of the colorectum: comparison with traditional adenoma

Aim-Serrated adenoma is a recently described category of colorectal adenoma. The aim of this study was to determine whether serrated adenomas have clinicopathological findings distinct from "traditional" adenoma. Methods-Colonoscopy records for 1995-1998 were reviewed, and all traditional adenomas and serrated adenomas identified. Tumour site and endoscopic configuration were compared between the two types of adenoma. In polypectomised lesions, size and grade of dysplasia were compared between the two groups. Results-There were 3305 traditional adenomas and 43 serrated adenomas. Serrated adenomas were more often found in the rectosigmoid colon than the traditional adenomas (67.5% v 42.2%, p = 0.0008). Polypectomy was more often done for serrated adenomas (27 of 43 lesions, 62.8%) than for traditional adenomas (626 of 3305 lesions, 18.9%, p < 0.0001). Size (mean (SD) maximum dimension, 12 (6) mm v 13 (3) mm) and incidence of high grade dysplasia (14.8% v 13.6%) in endoscopically removed specimens were not different between the two types. Conclusions-The therapeutic judgement applied to the management of traditional adenoma seems to be appropriate for serrated adenoma.