Peg cells and ciliated epithelium (normal constituents of the fallopian tube lining) define tubal metaplasia in the endometrium.
Ciliated cells line the fallopian tube and often, the surface endometrial cells exhibit cilia during the proliferative phase of the menstrual cycle. However, endometrial glands lined by ciliated cells is not a normal finding. Extensive tubal metaplasia is related to hyperestrogenic states such as anovulatory cycles and hormone replacement therapy.1
1 Nucci MR, Oliva Esther. Gynecologic Pathology: Foundations in Diagnostic Pathology. Philadelphia, PA: Elsevier: 2009: 222.