Coexistence of adenomyosis uteri and endometrial cancer is associated with an improved prognosis compared with endometrial cancer only.

The present study aimed to identify differences in protein expression in cases of endometrioid endometrial cancer (EEC) with and without coexisting adenomyosis uteri (AM), and to evaluate the histopathological and prognostic distinctions. The total cohort included 22 patients in Group A (patients with concomitant AM and EEC) and 35 patients in Group B (patients affected only by EEC). Evaluation of the following factors was performed: Tumour grade, International Federation of Gynaecology and Obstetrics (FIGO) stage, survival, and expression of estrogen receptor β (ERβ), glycodelin and inhibin βB. Group A (AM and EEC) was associated with a lower tumour grade (G1, 90.9 vs. 45.7%; P=0.001) and a lower FIGO stage (FIGO stage I, 100 vs. 80%; P=0.002) compared with Group B (EEC only). In the survival analysis, Group A was associated with a significantly higher 5-year survival rate (95 vs. 82%; P=0.024) than Group B. In addition, the expression of ERβ in Group A was significantly higher (P<0.001), whereas the expression of glycodelin is significantly lower (P=0.028), compared with Group B. The results of the present study indicate that the presence of AM in cases of EEC may be a positive prognostic factor.