The overall architecture is regular. The crypts are mildly elongated and towards the surface the epithelium has a serrated or 'saw-tooth' outline. There is no dysplasia. Although the epithelium bears a superficial resemblance to incomplete intestinal metaplasia in the stomach it is not truly metaplastic. Furthermore, cell turnover time is decreased, not increased as would be expected in hyperplastic states. The resultant 'hyper-mature' cells migrate towards the lumen in a spiral fashion giving rise to the serrated appearance.