The sensitivity of cervical cytology for detection of endometrial carcinoma is poor. In patients with known endometrial cancer, the Papanicolaou (Pap) smear will contain malignant cells less than 50% of the time. If the Pap smear does detect atypical or malignant cells, often the patient will have endometrial hyperplasia or carcinoma. Healthy women shed endometrial cells during the first half of their menstrual cycle. Endometrial cells should not be found on Pap smears from postmenopausal women. The presence of any endometrial cells on cervical cytology in a postmenopausal woman is associated with endometrial hyperplasia or cancer. Endometrial biopsy should be done if cervical cytology detects atypical or malignant endometrial cells in any woman or normal endometrial cells in a postmenopausal woman (Burk, Cherkis, Eddy, Gondos, Ng, Yancey)