Endometrial hyperplasia is an overgrowth of the mucous layer lining inside the uterus (called endometrium), usually secondary to hyperstimulation by estrogen (a sex hormone found in the female body).
Estrogen stimulates the growth of endometrial cells, a process that is subsequently reversed by the action of progesterone.
Hyperplasia may be due to different causes (exogenous estrogen administration, excessive ovarian production of them …) and can be of different degrees, being the most widely accepted classification, the divide in:
