Sonographic evaluation of the uterus in postmenopausal women receiving tamoxifen: Characterization of mid-uterine abnormalities

Background: Tamoxifen is known to exert agonist estrogenic effects on the uterus. Its use in postmenopausal women has also been associated with various endometrial and uterine abnormalities that can be detected by endovaginal sonography. Objective: To study postmenopausal patients receiving tamoxifen who were referred for evaluation following the detection of abnormal uterine findings by endovaginal sonography. Methods: Fifty-two women treated with tamoxifen for breast cancer who were found to have an abnormal uterine sonogram constituted the study population. Uterine sonograms were reviewed and clinical and sonographic data were correlated with the results of the histologic examinations. Results: Forty-five women demonstrated a thickened mid-uterine structure. Of these, in thirty-nine patients (87%) either no tissue or scant fragments of normal endometrium were obtained on curettage, and six women (13%) had endometrial hyperplasia. Seven women had fluid loculation lined by thin endometrium. Their subsequent histologic examination was normal. The sonograms of the women who demonstrated an appearance of a thickened endometrium but no neoplasia, characteristically demonstrated hyperechogenic cystic area with no midline echo. Conclusions: Among 52 postmenopausal patients receiving tamoxifen presented with an abnormal uterine sonogram, 39 (75%) women were found to have a thick mid-uterine structure resembling a thickened endometrium without histologic evidence of neoplasia. This phenomenon can be characterized by typical sonographic features, and may be differentiated from other uterine abnormalities.