Benign endometrial adenofibroma and polyp in patients receiving tamoxifen: findings on transvaginal ultrasonography and magnetic resonance imaging

Abstract

Tamoxifen, a selective estrogen receptor modulator, is widely used to treat breast cancer, but an association has been reported between tamoxifen and the development of endometrial lesions, including endometrial carcinoma, endometrial polyps, and endometrial hyperplasia. There have also recently been a few reports on the relation between tamoxifen and adenofibroma. We present two case reports, one of a patient with a uterine adenofibroma and one of a patient with an endometrial polyp, both of whom received tamoxifen. Cases 1 and 2 are 75- and 65-year-old postmenopausal women, respectively, undergoing tamoxifen therapy. In both cases, endometrial thickening and many small cysts in the uterine cavity were revealed by transvaginal ultrasonography or magnetic resonance imaging. Postoperative microscopic examination confirmed the mass as an adenofibroma in case 1 and as an endometrial polyp in case 2.

Adenofibroma of the endometrium protruding into the vaginal cavity: Findings on transvaginal ultrasonography, MRI and CT

“…A number of recent reports have examined relationships between tamoxifen treatment and adenofibroma 9,10 , 12 . Tamoxifen, a selective estrogen receptor modulator (SERM), acts as a partial estrogen receptor agonist in addition to an antagonist, and the antiestrogenic properties are responsible for the effectiveness of this agent as a breast cancer treatment.…”

“…Tamoxifen is associated with a relative risk ratio of 1.5–2.5 for the development of endometrial carcinoma 13 . Although the causal relation between tamoxifen and adenofibroma is not definitive, characteristic MRI and ultrasonographic findings are common 9,10 , 12 . However, when typical MRI findings (fibrous core and intratumoral cyst in thickened endometrium) are absent, distinguishing between endometrial polyp and endometrial carcinoma is difficult 8 .…”