Diagnostic pitfalls of ultrasonographic uterine screening in women treated with tamoxifen.

Recent reports of an association between tamoxifen treatment for breast cancer and endometrial pathology prompted a screening program for women receiving tamoxifen. Twenty-two women were examined; 15 were asymptomatic, and 7 were referred because of abnormal vaginal bleeding. All underwent vaginal ultrasonography followed by endometrial sampling. The sonographic studies showed endometrial abnormalities in all 22 women--typically, irregular thickening of the endometrium. Some had cystic formations, and three had fluid in the endometrial cavity. No pathology or inadequate material was found in the endometrial samples from the 15 asymptomatic women. Endometrial polyps were suspected sonographically and removed from two of the five women with vaginal bleeding. The discrepancy between the sonographic findings and histology in the asymptomatic women could have been due to stromal edema from tamoxifen treatment. Abnormal ultrasonographic findings in asymptomatic women treated with tamoxifen probably represent insignificant changes in the endometrial architecture and not a true abnormality. The need for routine endometrial sampling or hysteroscopy in every case is therefore questionable.