This study evaluated the clinical significance of endometrial cells in Papanicolaou test (Pap test). A retrospective study was performed from the cytological database of Seoul National University Hospital. The results of Pap tests of women aged 40 years or older between January 1998 and December 2007 were sorted. Medical records were reviewed to identify the presence of endometrial cells from cytology, and cytologic and histologic follow-ups were performed to determine the clinical significance of the lesions. Among 75,673 Pap cases, 832 cases presenting normal endometrial cells (nEMCs) were included in this study. Their follow-up data are as follows: 800 with nEMCs, 5 with atypical EMCs (aEMCs), and 27 with endometrial cancer cells (EMCCs) on cytologic and histologic follow-ups. Significant endometrial or cervical diseases were found in 0.5%, 40%, and 100% of the cases on the following-up the pathologic examination of the women with nEMCs, aEMCs, and EMCCs, respectively. Unlike aEMCs and EMCCs, nEMCs on Pap tests did not increase the risk of developing endometrial hyperplasia or endometrial cancer in women aged 40 years or older. There is no clinical benefit to perform routine endometrial work-up in women with nEMCs, as recommended in the 2001 Bethesda System. However, symptomatic women with nEMCs on Pap test should perform endometrial work-up regardless of menopausal status.
Keywords: Bethesda system; cervical cytology; endometrial neoplasm.