Benign proliferation of the endometrium in the uterus. endometrial hyperplasia is classified by its cytology and glandular tissue. there are simple, complex (adenomatous without atypia), and atypical hyperplasia representing also the ascending risk of becoming malignant.

Endometrial hyperplasia is a condition of excessive proliferation of the cells of the endometrium, or inner lining of the uterus. Most cases of endometrial hyperplasia result from high levels of estrogens, combined with insufficient levels of the progesterone-like hormones which ordinarily counteract estrogen's proliferative effects on this tissue. This may occur in several settings, including obesity, polycystic ovary syndrome, estrogen producing tumours (e.g...