Alerts and Notices
SynopsisEndometrial 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)
- Hyperplasia without atypia (benign)
- Atypical hyperplasia (precancerous)
N85.00 – Endometrial hyperplasia, unspecified
237072009 – Endometrial hyperplasia
Differential Diagnosis & Pitfalls
- Endometrial adenocarcinoma
- Atrophic postmenopausal bleeding – Thin endometrial stripe on ultrasound.
- Endometrial polyp – May appear as thickened endometrial stripe on transvaginal ultrasound. Saline sonohysterogram can help identify.
- Anovulatory bleeding in premenopausal woman – Will usually have irregular menses.
- Intracavitary leiomyoma (fibroid) – May be seen on transvaginal ultrasound and/or saline sonohysterogram.
- Coagulation disorders (inborn or iatrogenic) – Can be ruled out with labs.
- Hypothyroidism – Can be ruled out with labs.
Drug Reaction DataBelow is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.