Endometrial hyperplasia classification
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Endometrial hyperplasia is further classified based on histology into simple and complex types. Endometrial hyperplasia can also be classified based on the presence or absence of cellular atypia; hyperplasia with cellular atypia and hyperplasia without cellular atypia.
The World Health Organization (WHO) Classification System
The WHO Classification (1994)
- Endometrial hyperplasia may be classified based on glandular complexity and nuclear atypicality into the following types:
Simple hyperplasia with cellular atypia
Simple hyperplasia without cellular atypia
Complex hyperplasia with cellular atypia
Complex hyperplasia without cellular atypia
The New WHO Classification (2014)
- The updated WHO classification has been proposed to simplify clinical decision making, particularly when making treatment choices.
- Simple hyperplasia without atypia
- Simple hyperplasia is characterized by:
- Complex hyperplasia without atypia
- Complex hyperplasia without atypia is defined as:
- Glands with abnormal, irregular architecture set in a background of scant intervening stroma
- Some stroma must be present,
- Basement membrane lining individual glands and a rim of intervening endometrial-type stroma between them. In addition to back-to-back and cribriform-like arrangements, other glandular architectural abnormalities warranting designation of complex hyperplasia include
- Infoldings, and budding
- Squamous or morular metaplasia
- Eosinophilic and ciliated cell changes
- Simple hyperplasia with atypia
- Complex hyperplasia with atypia
- Increased gland-to-stroma ratio (≥3:1)
- Gland complexity—caused by:
- Outward budding
- Internal papillary infoldings
- Internal bridge
- Hyperplasia without atypia
- Atypical hyperplasia/endometrioid intraepithelial neoplasia
The Endometrial Intraepithelial Neoplasia (EIN) Classification
Endometrial changes may be classified according to the International Endometrial Collaborative Group into two types:
- Benign hyperplasia (a hormone dependent diffuse lesion, which is polyclonal)
- Benign endometrial hyperplasia is mostly observed with anovulation or after prolonged exposure to estrogen.
- The morphology of endometrial hyperplasia varies from proliferative endometrium with a few cysts to heavier endometria with many dilated and contorted glands that are designated as "cystic glandular hyperplasia," "mild hyperplasia," or "simple hyperplasia."
- Endometrial intraepithelial neoplasia
- Endometrial precancers
- Epithelial crowding depicts less stromal volume which is approximately half of total tissue volume in non secretory endometrium
- Typically cells appear morphologically clonal and distinct from the surrounding endometrium.
- With advanced stage, it may become a more diffuse lesion
- In the beginning a localized clonal proliferation, which is monoclonal and neoplastic (EIN)
- The D-score is an integral part of the EIN classification :
- It is a measure of stromal volume as a proportion of total tissue volume (stroma + epithelium + gland lumen)
- The D-score is assigned based on evaluation with computerized morphometry
- Using this method, specimens are classified as:
- Benign (D >1)
- Indeterminate (0< D <1)
- EIN (D <0).
- Using this method, specimens are classified as:
- ↑ Scully RE. Histological typing of female genital tract tumours. Springer; 1994.
- ↑ Endometrial hyperplasia. Radiopedia. http://radiopaedia.org/articles/endometrial-hyperplasia-1 Accessed on March 3, 2016.
- ↑ Jorizzo JR, Chen MY, Martin D, Dyer RB, Weber TM (2002). "Spectrum of endometrial hyperplasia and its mimics on saline hysterosonography". AJR Am J Roentgenol. 179 (2): 385–9. doi:10.2214/ajr.179.2.1790385. PMID 12130438.
- ↑ Emons G, Beckmann MW, Schmidt D, Mallmann P, Uterus commission of the Gynecological Oncology Working Group (AGO) (2015). "New WHO Classification of Endometrial Hyperplasias". Geburtshilfe Frauenheilkd. 75 (2): 135–136. doi:10.1055/s-0034-1396256. PMC 4361167. PMID 25797956.
- ↑ Mutter GL (2000). "Endometrial intraepithelial neoplasia (EIN): will it bring order to chaos? The Endometrial Collaborative Group". Gynecol Oncol. 76 (3): 287–90. doi:10.1006/gyno.1999.5580. PMID 10684697.
- ↑ Baak JP, Mutter GL (2005). "EIN and WHO94". J Clin Pathol. 58 (1): 1–6. doi:10.1136/jcp.2004.021071. PMC 1770545. PMID 15623473.
- ↑ Baak JP, Ørbo A, van Diest PJ, Jiwa M, de Bruin P, Broeckaert M, Snijders W, Boodt PJ, Fons G, Burger C, Verheijen RH, Houben PW, The HS, Kenemans P (July 2001). "Prospective multicenter evaluation of the morphometric D-score for prediction of the outcome of endometrial hyperplasias". Am. J. Surg. Pathol. 25 (7): 930–5. PMID 11420465.