Uterus
Non tumor
Endometrial metaplasia

Author: Nat Pernick, M.D. (see Authors page)

Revised: 18 January 2017, last major update March 2012

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed search: endometrial metaplasia uterus

Subtypes: clear cell, eosinophilic (oxyphilic), intestinal, mucinous, papillary, squamous, stromal, syncytial, tubal
Table of Contents
Definition / general
Cite this page: Endometrial metaplasia. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/uterusmetaplasia.html. Accessed November 22nd, 2017.
Definition / general
  • Often due to hormonal or irritative stimuli (J Clin Pathol 2011;64:97, Am J Surg Pathol 1980;4:525)
  • Must evaluate metaplasia separately from hyperplasia
  • Tends to be associated with adenocarcinoma and is more common in women at high risk for endometrial carcinoma



Clear cell metaplasia
  • Tall cells, apical nuclei and clear cytoplasm; no atypia
  • Clear cell change by itself is nonspecific
  • Case reports: with atypical endometrial hyperplasia (Ann Diagn Pathol 2003;7:381)
  • DD: clear cell adenocarcinoma

Images hosted on other servers:

Atypical endometrial hyperplasia with clear cell change




Eosinophilic (oxyphilic) metaplasia
  • Also called eosinophilic cell change
  • Estrogen induced, resembles atypical hyperplasia except there is no atypia
  • Nonspecific and very common; associated with mucinous metaplasia and ciliated (tubal) change (Mod Pathol 2005;18:1243)
  • MUC5AC+

Images hosted on other servers:

Nature.com images:

Eosinophilic
cell change in
endometrioid
adenocarcinoma

Eosinophilic cell
change and MUC5AC+
in normal proliferative
endometrium




Intestinal metaplasia
  • Rare


Micro images

Images hosted on other servers:

Intestinal metaplasia



Positive stains



Mucinous metaplasia
  • Resembles endocervical mucosa (Int J Gynecol Pathol 1983;1:383); benign features
  • Associated with hyperestrogen states, endometrial polyps
  • Multifocal lesions associated with lobular endocervical glandular hyperplasia / pyloric gland metaplasia (Histopathology 2009;54:184)
  • May produce mucometra if cervical stenosis present
  • Mucin pools are associated with neutrophils


Micro images

Images hosted on other servers:


Left: simple mucinous metaplasia in the basalis of an atrophic endometrium
Middle: Complex papillary mucinous metaplasia in curettings
Right: Complex endometrioid hyperplasia with a glandular space lined by micropapillary mucinous metaplasia (arrow)


Nature.com images:

Mucinous metaplasia in adenocarcinoma




Papillary proliferation / papillary change
  • Rare, usually postmenopausal women
  • May be similar to papillary syncytial change
  • Usually benign behavior
  • Polypectomy or curettage appears to be adequate treatment (Am J Surg Pathol 2001;25:1347)
  • More aggressive treatment may be needed for extensive complex papillary proliferations


Gross description
  • 0.7 cm to 3.0 cm in size, 2/3 occur in endometrial polyps


Micro description
  • Focal areas of fibrovascular cores without atypia, usually near endometrial surface
  • Either simple or complex papillary patterns
  • Often metaplastic epithelial changes


Micro images

Images hosted on other servers:

Papillae are limited to the surface
epithelium and composed of
bland uniform lining cells



Cytology description


Differential diagnosis
  • Well differentiated / low grade papillary adenocarcinoma


Squamous metaplasia
  • Occurs in normal or hyperplastic endometrium, polyps and leiomyomas; also as part of malignant processes
  • Usually diffuse (adenoacanthosis) or in morules (rounded aggregates of bland cells with indistinct cytoplasmic borders)
  • Usually in premenopausal women with exogenous hormones (Arch Pathol Lab Med 1995;119:458) or with polycystic ovary disease; also associated with foreign body reactions, chemical irritants and endometritis
  • Note: central necrosis of morules is common and not specific for malignancy
  • Ichthyosis uteri: complete replacement of endometrium by squamous epithelium; may be associated with malignancy (Diagn Pathol 2006 May 19;1:8)


Micro images

Images hosted on other servers:

Squamous metaplasia

Left: with squamous cell carcinoma; right: with endometrioid carcinoma



Nature.com images:

Squamous and
mucinous
metaplasia post
tamoxifen therapy



Differential diagnosis



Stromal metaplasia


Micro images

Images hosted on other servers:

Endometrial stromal
nodule with smooth
muscle metaplasia



Differential diagnosis
  • Retained fetal parts



Syncytial change
  • Also known as papillary syncytial change, surface syncytial change
  • Finding in endometrial biopsies and curettings from patients with uterine bleeding
  • Associated with anovulatory dysfunctional bleeding, endometrial hyperplasia, estrogen usage or other hormonal treatment
  • Appears to be degenerative, not reparative (Int J Gynecol Pathol 2008;27:534)


Micro description
  • Denuded endometrial surface produced by breakdown or breakthrough bleeding covered by sheet-like plaque of regenerating epithelial cells, often eosinophilic, without discrete cell boundaries (Mod Pathol 2000;13:309)
  • Nuclear debris, neutrophils and rounded clumps of endometrial stromal cells usually present
  • Usually no papillae with fibrovascular cores
  • May resemble microglandular hyperplasia due to small glandular lumina or pseudolumina


Micro images

Images hosted on other servers:

Surface papillary syncytial change

p16+



Nature.com images:

Surface syncytial change



Positive stains



Tubal (ciliated cell) metaplasia
  • Markedly increased ciliated cells (nonmetaplastic endometrium have some ciliated cells), resembles fallopian tube; often seen with endometrial hyperplasia and other hyperestrogenic states
  • Presence of atypia does not affect prognosis (Mod Pathol 2011;24:1254)


Micro Images

Images hosted on other servers:

Tubal-type ciliated epithelium

Tubal metaplasia

Complex stellate; complex, cribriform glands; mosaic p16 positivity



Nature.com images:

Hyperplastic endometrium
with ciliary change
(tubal metaplasia)



Positive stains