Premalignant Lesions Of The Endometrium

Premalignant endometrial lesions are a characteristic sequence of endometrial hyperplasia (EH) that progress to endometrial carcinoma (EC). Two types of precursor lesions can lead to the two types of endometrial carcinoma. Atypical hyperplasia/endometrioid intraepithelial neoplasia (AH/EIN) is the premalignant phase for endometrioid adenocarcinoma or type 1 endometrial carcinoma. Over 90% of endometrioid carcinomas are thought to develop from preexisting AH/EIN lesions. Type 1 endometrial carcinoma is typically seen in pre and peri-menopausal women. The etiologic factors include the predominance of estrogen combined with progesterone insufficiency. Rarely, atypical hyperplasia is associated with a secretory or mucinous cell type. Endometrial intraepithelial carcinoma (EIC) is thought to be the precursor lesion for the type 2 or serous carcinoma and a few of the endometrial clear cell carcinomas. Type 2 serous carcinoma is seen in post-menopausal women and is associated with atrophy of the endometrium.Type 1 endometrial carcinoma accounts for nearly 80 to 85% of all endometrial malignancies. AH shows many of the mutations that are seen in invasive endometrioid carcinoma. P53 inactivation is the driving mutation for serous carcinoma. Type 2 serous carcinoma is about 3 to 10% of all newly diagnosed cases, and clear cell carcinoma and other rare endometrial carcinomas together account for the rest.