Endometrial Hyperplasia

Michael E. Toaff, MD, MSc

What is Endometrial Hyperplasia

What is the Treatment for Endometrial Hyperplasia

What is Endometrial Hyperplasia

Endometrial hyperplasia is an overgrowth or thickening of the endometrium (lining of the uterus) which may involve part or all of the endometrium. This diagnosis can only be made by the pathologist who examines a sample of tissue removed from the thickened endometrium by a procedure such as endometrial biopsy, D&C, or hysteroscopy. Examination under the microscope of the endometrial tissue shows proliferation (excessive growth) of both the endometrial glands as well as the surrounding tissue (stroma). The glands in this condition are more crowded than normal and they show additional changes. However, the key determinant of biological behavior, i.e., potential for malignancy, is the presence of changes known as atypia within the hyperplastic tissue. There are a variety of types of hyperplasia (simple, adenomatous) which are all benign as long as they do not show "atypia". Both hyperplasia with atypia and without atypia may regress spontaneously over months or years. However, whereas hyperplasia without atypia rarely progresses to endometrial cancer, hyperplasia with atypia is a precancerous condition that may progress to overt malignancy. Complex atypical hyperplasia progresses to endometrial carcinoma in 29% of women. Hyperplasia without atypia (including adenomatous type) can be effectively treated with progestins (hormones with progesterone activity). Following continuous progestin treatment of 3-4 months duration, repeat sampling of the endometrial lining is required to demonstrate resolution of the hyperplasia and exclude the presence of atypia.

Hyperplasia usually develops in the presence of continuous estrogen stimulation unopposed by progesterone. During adolescence and in the years before menopause women may have numerous cycles without ovulation (anovulatory) during which there is continuous unopposed estrogen activity. Polycystic ovary syndrome is another condition in which women are anovulatory and have unopposed estrogen effect. Similarly hormone replacement therapy consisting of estrogen without progesterone may lead to endometrial hyperplasia. In these situations, the addition of progesterone (by taking a progestin) or resumption of ovulation (spontaneously or with medications) can eliminate hyperplasia, especially hyperplasia without atypia.

A majority of hyperplastic lesions regress spontaneously.  During a mean follow up of 11.4 years, disease regressed in 69% of women with Simple atypical hyperplasia and 57% of patients with Complex atypical hyperplasia.  Eight percent of Simple atypical hypeplasia and 23% of Complex atypical hyperplasia progressed to carcinoma.  In another study, Simple hyperplasia without atypia regressed in 79% over 3 years as did 94% of Complex hyperplasia without atypia.  Complex hyperplasia with atypia regressed in 55%.

Hyperplasia without atypia may also resolve spontaneously or following a D&C. On the other hand, hyperplasia with atypia tends to persist even after treatment with progestin. Currently, endometrial hyperplasia is the indication for 5% of all hysterectomies performed in the U.S. In 43% of women undergoing hysterectomy because of atypical hyperplasia diagnosed by endometrial biopsy the removed uterus contained endometrial carcinoma.  It is obviously critical to evaluate the uterus before surgery with a D&C when a biopsy revealed endometrial hyperplasia because of the high risk that a concurrent cancer is present.  During hysterectomy the uterus should be inspected thoroughly and the surgeon should be ready to perform lymph node dissection if cancer is found. Hyperplasia, even after successful treatment, may recur, especially if conditions of unopposed estrogen persist. It is therefore necessary to assure that unopposed estrogen condition does not continue by giving progesterone intermittently or, in younger women, birth control pills. Also, it is important to monitor such patients closely (using ultrasound, endometrial biopsies etc.) long after completion of a successful course of treatment.

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What is the Treatment for Endometrial Hyperplasia

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