Clinico-pathological aspects of colorectal serrated adenomas.

Aim: To study the association of colorectal serrated adenomas (SAs) with invasive carcinoma, local recurrence, synchronicity and metachronicity of lesions.

Methods: A total of 4,536 polyps from 1,096 patients over an eight-year period (1987-1995) were retrospectively examined. Adenomas showing at least 50% of serrated architecture were called SAs by three reviewing pathologists.

Results: Ninety-one (2%) of all polyps were called SAs, which were found in 46 patients. Invasive carcinomas were seen in 3 out of 46 (6.4%) patients, of whom one was a case of familial adenomatous polyposis (FAP). A male preponderance was noted and features of a mild degree of dysplasia were seen in majority (n=75, 83%) of serrated adenomas. Follow-up ranged 1-12 years with a mean time of 5.75 years. Recurrences of SAs were seen in 3 (6.4%) cases, synchronous SAs in 16 (34.8%) cases and metachronous SAs in 9 (19.6%) cases.

Conclusion: Invasive carcinoma arising in serrated adenoma is rare, accounting for 2 (4.3%) cases studied in this series.