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Table of Contents
Definition / general | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Positive stains | Differential diagnosis | Additional referencesCite this page: Benign (non atypical) endometrial hyperplasia. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/uterusbenignhyperplasia.html. Accessed July 16th, 2017.
Definition / general
- Prior to 2014, the World Health Organization classified endometrial hyperplasia as simple versus complex, and nonatypical versus atypical
- This system suffered from significant interobserver variation (Am J Surg Pathol 2008;32:691)
- Reproducibility improved with a two tier classification (Histopathology 2014;64:284, Int J Gynecol Pathol 2008;27:318)
- Accordingly, the classification system was simplified in 2014, and now divides hyperplasia into two categories, benign (nonatypical) hyperplasia and atypical hyperplasia (equivalent to endometrial intraepithelial neoplasia / EIN)
- The terms "simple" and "complex" have been removed from the classification; they, however, remain in parts of the following text when citing data prior to the 2014 WHO classification
- Non atypical hyperplasia is part of the spectrum of endometrial changes due to unopposed estrogen stimulation
- Incidence: 142 per 100,000 woman-years, peaks in early 50s (Am J Obstet Gynecol 2009;200:678)
- 2 - 4x risk of progression to endometrial carcinoma compared to general population (compared to 45x for atypical hyperplasia / EIN) (Cancer 2005;103:2304)
- < 1% prevalence of carcinoma diagnosis beyond 1 year after diagnosis of benign endometrial hyperplasia (Mod Pathol 2005;18:324, Hum Pathol 2008;39:866)
Treatment
- Progestins, levonorgestrel-releasing intrauterine system (Menopause 2008;15:1002)
Gross description
- Increased endometrial volume, qualitatively different from normal cycling endometrium
Gross images
Images hosted on other servers:
Endometrial hyperplasia has lush
fronds of hyperplastic endometrium
Microscopic (histologic) description
- Gland to stroma ratio is greater than 1:1 (glands occupy more than 50% of the surface area); these areas of "gland crowding" still contain small amounts of stroma in between glands, and the individual glandular contours can be easily distinguished
- Glands are usually round or elongated; however, shape and size irregularity are common including cystic dilation
- Lining epithelium usually displays proliferative-type morphology with pseudostratified or mildly stratified columnar cells containing elongated cigar shaped nuclei
- Metaplastic change (tubal, mucinous, squamous, secretory) can be seen
- Cellular stroma with variable mitotic activity, uniformly distributed blood vessels
- By definition, there is no cytologic atypia and no significant complexity (glandular confluence with loss of individual glandular contours, cribriform or microacinar architecture)
Microscopic (histologic) images
Images hosted on PathOut servers:
Benign endometrial hyperplasia
Cytology description
- May be diagnosed as proliferative endometrium by endometrial brush cytology (Am J Clin Pathol 2000;114:412)
Positive stains
- PTEN (usually, J Med Assoc Thai 2008;91:1161)
Differential diagnosis
- Artifacts: fragmented endometrium with artificially crowded (compressed) glands
- Chronic endometritis: may have reactive glandular changes causing abnormal gland shapes and variable metaplasia; but has plasma cells, stromal spindling and edema and surface neutrophils, and gland to stroma ratio < 1:1
- Cystic atrophy: glandular to stroma ratio is < 1:1, glands lined by flat to cuboidal inactive epithelium, stroma is dense and atrophic
- Disordered proliferative endometrium: variation in glandular size and shape, metaplasia and patchy breakdown, but with a gland to stroma ratio < 1:1
- Endometrial polyp: fibrotic stroma with dilated, thick-walled blood vessels
Additional references
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