An abnormal thickening of the uterine lining, often from estrogen without enough progesterone.
Endometrial hyperplasia is an overgrowth of the uterine lining. It can result from estrogen stimulation that is not balanced by progesterone, and may cause abnormal bleeding.
Some forms carry a risk of progressing to cancer, so it is evaluated by a clinician, often with an endometrial biopsy.