Iatrogenic endometrial megapolyps in women with breast carcinoma

Tamoxifen, a widely used drug in adjuvant therapy of breast carcinoma, is now being tested for its effectiveness in chemoprevention. Although its side effects are few, tamoxifen increases the incidence of proliferative lesions of the endometrium, which theoretically should be preventable with progestational agents.

Two postmenopausal women treated with tamoxifen and progestational agents for breast carcinoma developed uterine enlargement and intermittent spotting. Hysterectomy revealed benign endometrial megapolyps with marked stromal decidualization and edema.

The value of multihormonal therapy in breast carcinoma is not established, and the addition of progestogens to tamoxifen may not reduce of developing endometrial lesions, including carcinoma. In both our cases, such a regimen did not prevent the occurrence of endometrial polyps which, although histologically benign, were usually large and thought clinically to be malignant. Periodic gynecologic assessment should be part of the follow-up of all women on long-term tamoxifen therapy.