What are the types of thick endometrium?

Simple Endometrial Hyperplasia (Without Atypia):

This type of endometrial hyperplasia has very normal looking cells that aren’t likely to become cancerous. This condition will also improve without treatment. Hormone therapy will helps in some cases.

Simple Or Complex Atypical Endometrial Hyperplasia:

An overgrowth of abnormal cells which causes this kind of precancerous condition. Without any treatment, the risk of endometrial or uterine cancer will increase.