Transvaginal US and hysterosonography in postmenopausal women with breast cancer receiving tamoxifen: correlation with hysteroscopy and pathologic study.

Tamoxifen citrate therapy increases the prevalence of benign and malignant uterine lesions. At transvaginal ultrasonography (US), the finding of a thickened central endometrial complex, with or without cystic changes, is often nonspecific and may be caused by an endometrial polyp, submucosal leiomyoma (fibroid), endometrial hyperplasia, carcinoma, or cystic atrophy. In addition, because of an increased prevalence of adenomyosis or adenomyosis-like changes in women receiving tamoxifen, proper transvaginal US assessment of endometrial thickness and abnormalities is difficult in some women. Hysterosonography, as an adjunct to transvaginal US, allows identification of intracavitary lesions and focal and diffuse endometrial abnormalities and helps determine whether an abnormality is endometrial or subendometrial. Endometrial polyps may be seen at transvaginal US as nonspecific thickening of the endometrial complex, with or without cystic changes. At hysterosonography, they appear as an echogenic mass with smooth margins. Submucosal leiomyomas may protrude into the endometrial cavity, causing false endometrial thickening at transvaginal US. Hysterosonography shows a round structure arising from the myometrium with a thin, overlying endometrium. At transvaginal US, when the endometrium cannot be accurately measured or when there is a nonspecific thickened central endometrial complex, hysterosonography can provide additional information and can help in the triage for hysteroscopic versus nondirected endometrial biopsy. Correlation of transvaginal US and hysterosonographic findings with hysteroscopic and pathologic findings enhances understanding of these changes, as well as the limitations and potential pitfalls of both imaging techniques.