Unexplained postmenopausal uterine bleeding from atrophic endometrium: Histopathological and hormonal studies

Abstract

Objective: To study the histopathology of endometrium and the serum concentration of sex steroid hormones in different types of atrophic endometrium associated with postmenopausal uterine bleeding (PMB). Design: Prospective observational study. Main outcome measures: Types of atrophic endometrium with PMB and serum concentration of sex steroid hormones in each type during and between episodes of bleeding. Materials and methods: One hundred and nine patients with PMB were investigated. Transvaginal ultrasonography was performed for all the cases. The endometrium was considered atrophic if its thickness was <4 mm. Endometrial sampling was done and submitted to histopathological study for 97 cases of atrophic endometrium. Serum concentration of total testosterone (T), androstenedione (A), esterone (E1) and estradiol (E2) and sex-hormone binding globulin were estimated for patients with atrophic endometrium during episodes of bleeding and in 47 cases were estimated also between episodes of bleeding. Results: Organic lesions were detected in 12 cases (11.0%) and atrophic endometrium was discovered in 97 cases (88.99%). The types of atrophic endometrium were as follow: atrophic inactive 46 cases (47.42%), atrophic/weakly proliferative 38 cases (39.19%), mixed with atrophic inactive and non-inactive 7 cases (7.21%) and cystic atrophic 6 cases (6.18%). Serum levels of all sex steroid hormones TT, A, E1, and E2 were significantly higher in atrophic/weakly proliferative than atrophic inactive endometria. Serum concentration of these sex steroid hormones was significantly lower during episodes of bleeding than between these episodes. Conclusions: There are 4 histological types of atrophic endometrium, atrophic inactive, atrophic/weakly proliferative (non-inactive), mixed (inactive and non-inactive) and cystic atrophic. Serum concentration of sex steroid hormones T, A, E1, and E2 was significantly higher and SHBG was significantly lower in cases of atrophic/weakly proliferative and mixed endometria than cases of atrophic inactive and cystic atrophic endometria. This may explain the development of endometrial adendocarcinoma on the top of atrophic endometrium. Concentration of these hormones was significantly higher between episodes of bleeding than during episodes of bleeding. This fluctuation may explain PMB from atrophic endometrium.

Keywords

• Postmenopausal bleeding
• Histological types of atrophic endometrium
• Sex steroid hormones in atrophic endometrium