A 52-year-old perimenopausal woman has had vaginal bleeding for a week. She has no medical problems and takes no medications. Hysteroscopy is performed and there is a single, 2-cm, smooth, soft mass protruding into the endometrial cavity. Biopsies are taken. What is the microscopic examination of this lesion most likely to show?

She has an endometrial polyp, seen most often in perimenopausal and postmenopausal women. The lesion can lead to abnormal bleeding but rarely gives rise to malignancy. Endocervical glands with squamous metaplasia are seen most often with chronic cervicitis. Papillae with marked cellular atypia are seen with the serous type of endometrial carcinoma. Smooth muscle cells in bundles characterize a leiomyoma, which may be submucosal. Tubular glands lined by clear cells with glycogen are seen with the rare clear cell carcinoma.