Carcinoma of the endometrium in patients treated with tibolone.

BACKGROUND

Tibolone is a synthetic steroid with estrogenic, androgenic and progestogenic properties, which has been used as an alternative to estrogen replacement therapy in several countries. One of its outstanding features is that it does not stimulate endometrial proliferation.

CASES

We report four cases of histologically diagnosed adenocarcinoma of the endometrium in women using tibolone.

CONCLUSIONS

Although we do not suggest causality between the use of tibolone and the development of endometrial malignancy, the association described should alert physicians to thorough investigation in patients presenting with vaginal bleeding while on tibolone, despite the absence of endometrial thickness by sonogram.