Abnormalities detected on transvaginal ultrasonography in tamoxifen-treated postmenopausal breast cancer patients may represent endometrial cystic atrophy

OBJECTIVE: This study was conducted to examine the histopathologic changes in tamoxifen-treated postmenopausal patients with endometrial thickness greater than or equal to 5 mm with transvaginal ultrasonography. STUDY DESIGN: Thirty-five tamoxifen-treated postmenopausal breast cancer patients underwent transvaginal pelvic ultrasonography with endometrial thickness greater than or equal to 5 mm followed by either curettage-hysteroscopy (n = 24), or hysterectomy (n = 11). Endometrial histopathologic findings were examined. RESULTS: Overall, endometrial polyps were the most common histopathologic finding (23 of 35 patients). Endometrial cystic atrophy was uncommonly detected in patients undergoing curettage-hysteroscopy (1 of 24 patients) compared with patients undergoing hysterectomy (9 of 11 patients). No cases of endometrial cancer or hyperplasia were detected. CONCLUSIONS: Endometrial polyps were a frequent finding in tamoxifen-treated postmenopausal women who had endometrial thickness greater than or equal to 5 mm with the use of transvaginal ultrasonography. Endometrial cystic atrophy may explain "thickened endometrium" on transvaginal ultrasonography in this patient population with no evidence of endometrial polyps, hyperplasia, or adenocarcinoma after surgical evaluation.