Endometrial Hyperplasia

What happens in endometrial hyperplasia

During a normal menstrual cycle, estrogen thickens the uterine lining in the first half of the cycle. After ovulation, progesterone stabilizes it, and when progesterone falls, the lining sheds as a period. When estrogen acts for long periods without progesterone, the lining keeps growing. Over time the glands become crowded, and in some cases the cells develop abnormal (atypical) features.

Types and cancer risk

Current classification (WHO) uses two categories:

Symptoms

• bleeding after menopause, even light spotting
• heavy menstrual bleeding or periods lasting longer than 7 days
• bleeding between periods
• periods closer together than 21 days
• irregular periods, or absent periods followed by heavy bleeding (common in PCOS)

Some people have no symptoms, and the thickening is found on an ultrasound for another reason.

Causes and risk factors

Anything that raises estrogen or reduces progesterone exposure:

• Obesity: fat tissue converts hormones into estrogen. The strongest common risk factor.
• Polycystic ovary syndrome: infrequent ovulation means little progesterone.
• Perimenopause: cycles without ovulation.
• Estrogen-only hormone therapy in people with a uterus.
• Tamoxifen for breast cancer, which acts like estrogen on the uterus.
• Never having been pregnant, early first period and late menopause.
• Diabetes and insulin resistance.
• Estrogen-producing tumors (rare), such as granulosa cell tumors of the ovary.
• Inherited conditions: Lynch syndrome and Cowden syndrome.

Diagnosis

1. Transvaginal ultrasound: measures the thickness of the lining. After menopause, a lining of 4 mm or less makes cancer very unlikely. A thicker lining, or persistent bleeding, needs tissue sampling.
2. Endometrial biopsy: a thin tube takes a sample through the cervix in the office. It takes a few minutes and causes cramping.
3. Hysteroscopy with dilation and curettage (D&C): a camera inspects the inside of the uterus and tissue is removed, when a biopsy is inconclusive or a polyp is suspected.

Only a tissue sample can tell hyperplasia from polyps or cancer.

Treatment

Hyperplasia without atypia

• Remove the trigger: weight loss, stopping unopposed estrogen, treating PCOS.
• Progestin therapy: the levonorgestrel intrauterine device (hormonal IUD) is the most effective first-line option, with high regression rates. Oral progestins are an alternative.
• Follow-up biopsies every 6 months until two consecutive biopsies are normal.
• Hysterectomy if hyperplasia persists or returns, bleeding continues, or by preference.

Atypical hyperplasia (EIN)

• Total hysterectomy is recommended for people who have finished having children, because of the high risk of current or future cancer. The ovaries may be kept in younger patients.
• Fertility-sparing treatment: for those who wish to become pregnant or cannot have surgery, high-dose progestin therapy (often a hormonal IUD with or without oral progestin) with biopsies every 3 to 6 months. Hysterectomy is advised after childbearing is complete.

Prevention

• maintaining a healthy weight
• taking a progestin with estrogen hormone therapy if you have a uterus
• regular progestin courses, combined hormonal contraception or a hormonal IUD for people with PCOS and infrequent periods
• prompt evaluation of abnormal bleeding
• annual review and prompt checks for bleeding while on tamoxifen

Frequently asked questions

What are the symptoms of endometrial hyperplasia?

The main symptom is abnormal uterine bleeding: heavy or long periods, bleeding between periods, periods closer than 21 days, or any bleeding after menopause. Some people have no symptoms and the condition is found on an ultrasound.

Is endometrial hyperplasia cancer?

No, but some forms can lead to cancer. Hyperplasia without atypia has a low risk of becoming cancer. Atypical hyperplasia is precancerous, and cancer is already present in a significant number of cases when the uterus is removed, so it is usually treated with hysterectomy.

What causes a thickened endometrium?

A thickened lining usually results from excess estrogen without enough progesterone, as with obesity, PCOS, perimenopause, estrogen-only hormone therapy or tamoxifen. Polyps and cancer can also thicken the lining, so a biopsy is needed to find the cause.

Can endometrial hyperplasia go away on its own?

Hyperplasia without atypia sometimes regresses on its own, especially when the cause, such as estrogen therapy, is removed. Progestin treatment makes regression much more likely. Atypical hyperplasia should always be treated.

How is endometrial hyperplasia treated?

Hyperplasia without atypia is usually treated with a progestin, most effectively a hormonal IUD, plus follow-up biopsies. Atypical hyperplasia is usually treated with hysterectomy, or with high-dose progestin and close monitoring for those who want to preserve fertility.