Cytologically Benign Endometrial Cells in the Papanicolaou Smears of Postmenopausal Women

ObjectiveThe objective of this study was to determine the clinical significance of the presence of benign endometrial cells in the Pap smears of postmenopausal women.MethodsA retrospective analysis of the clinical outcome of 297 postmenopausal women containing benign endometrial cells in their Pap smears was performed. All patients had subsequent endometrial biopsies or routine follow-up for 1-5 years. In addition, Pap smears of 253 of the patients were reviewed with particular reference to the morphology and type of the endometrial cells. Immunohistochemical staining with CD68 was performed in 15 selected cases to determine the origin of the stromal cells.ResultsOne hundred thirty-two (44%) women had endometrial biopsies while the remaining 165 (56%) were followed up by routine gynecologic examinations and repeat Pap smears. Endometrial lesions were detected in 14 patients of whom only 3 had significant lesions (2 atypical hyperplasias and 1 adenocarcinoma). Review of the Pap smears revealed benign superficial endometrial stromal cells in most cases (73%). Stromal cells showed CD68 positivity indicating a histiocytic origin. Glandular cells were present in 27%, either alone or in association with stromal cells. Statistical analysis revealed that the presence of endometrial glandular cells in Pap smears was associated with five times the likelihood of significant endometrial disease than found in women with normal Pap smears, although sensitivity and positive predictive value were very low (7.14 and 2.94%, respectively). Superficial endometrial stromal cells were not useful in predicting endometrial pathology.ConclusionSignificant endometrial lesions were present in 1% of postmenopausal women containing morphologically benign endometrial cells in the Pap smears. In the majority, the endometrial cells were of the superficial stromal type, which were demonstrated immunohistochemically to be histiocytes. The presence of endometrial glandular cells correlated significantly with endometrial pathology. Such an association was not observed in cases with stromal cells only.