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Endometrial hyperplasia
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Endometrial hyperplasia

Contributors: Mary N.W. Towner MD, Mitchell Linder MD
Other Resources UpToDate PubMed


Endometrial hyperplasia is an abnormal proliferation of the uterine endometrial glands due to effects of estrogen unopposed by progesterone. This condition can be benign or represent a precancerous endometrial lesion. Endometrial intraepithelial neoplasia (EIN; a type of endometrial hyperplasia) is a precursor to endometrial adenocarcinoma.

Endometrial hyperplasia occurs in both pre- and postmenopausal women, but is most common in women in their early 50s, during perimenopause. The diagnosis is rare in women younger than 30. Endometrial hyperplasia diagnosed after age 60 is more likely to be EIN.

Abnormal uterine bleeding or postmenopausal bleeding is the only symptom for the vast majority of patients.

Most risk factors for endometrial hyperplasia are conditions that expose the uterus to sustained estrogen without opposing progesterone. As such, obesity, polycystic ovarian syndrome (PCOS), anovulation, nulliparity, tamoxifen use, estrogen therapy without progesterone, and early menarche or late menopause are all well-defined risk factors for endometrial hyperplasia.

There are genetic syndromes that predispose women to endometrial hyperplasia, particularly Lynch syndrome (hereditary nonpolyposis colorectal cancer), which should be suspected when a woman has a family history of endometrial, colorectal, ovarian, intestinal, or renal cancers.

Nearly 40% of women diagnosed with EIN will be found to have endometrial adenocarcinoma at the time of hysterectomy. Of women diagnosed with endometrial hyperplasia who subsequently develop endometrial adenocarcinoma, time to progression is usually between 2.5 and 6 years, depending on the degree of histologic derangement.

There are 2 major systems for classifying endometrial hyperplasia, and pathologists may report results using either.

1) EIN schema (preferred, but less commonly used):
  • Benign endometrial hyperplasia (benign)
  • EIN (precancerous)
2) World Health Organization (WHO) 2015 schema:
  • Hyperplasia without atypia (benign)
  • Atypical hyperplasia (precancerous)


N85.00 – Endometrial hyperplasia, unspecified

237072009 – Endometrial hyperplasia

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Last Reviewed:06/06/2017
Last Updated:12/25/2018
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Endometrial hyperplasia
A medical illustration showing key findings of Endometrial hyperplasia : Vaginal bleeding, Menorrhagia
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