Endometrioid carcinoma

Topic Completed: 1 August 2010

Minor changes: 6 August 2020

Copyright: 2002-2020, PathologyOutlines.com, Inc.

PubMed search: endometrioid carcinoma [title]

Jamie Shutter, M.D.
Page views in 2019: 49,125
Page views in 2020 to date: 35,025
Cite this page: Shutter J. Endometrioid carcinoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/uterusendometrioid.html. Accessed August 11th, 2020.
Definition / general
  • Relatively indolent tumors that arise in background of endometrial hyperplasia
  • Also called type 1 endometrial carcinoma
  • Adenoacanthoma: endometrioid adenocarcinoma with well differentiated (benign appearing) squamous differentiation; similar prognosis as other well differentiated adenocarcinomas; prognosis is dependent on glandular, not squamous component
  • Associated with estrogen replacement therapy (usually well differentiated and endometrioid with good prognosis)
  • Rare if ovarian dysgenesis or castration
  • Rates much higher in white vs. black women
  • Both carcinoma and hyperplasia are linked to prolonged estrogenic stimulation without progestational agents; both are also associated with estrogen secreting tumors
Clinical features
  • 80% of endometrial carcinomas
  • Local or diffuse, invades through myometrium
  • Most women have Stage I disease, moderate or well differentiated tumors
  • 5 year survival - Stage 1 (90%), Stage 2 (30% - 50%), Stage 3 / 4 (20%)
Prognostic factors
Case reports
  • Well differentiated tumors: hysterectomy plus radiation therapy if greater than 50% myometrial invasion
  • Moderately differentiated tumors: hysterectomy plus radiation therapy if myoinvasive
Gross description
  • Usually large uterus if myometrial invasion, but uterus may be normal sized even with myometrial invasion if tumor begins in cornu
Gross images

Images hosted on other servers:

With leiomyosarcoma

Yellowish white tumor
originating from the
endometrium with sharply
delineated leiomyoma

Microscopic (histologic) description
  • Back to back endometrial-type glands of varying differentiation / atypia with no intervening stroma
  • May occasionally show a villoglandular pattern
  • Stroma present is usually desmoplastic, may have foamy cells due to tumor necrosis (not specific for carcinoma, derived from stroma not histiocytes; fat positive, mucin negative)
  • Adjacent endometrium often exhibits EIN or atypical hyperplasia
  • Vascular invasion is associated with chronic inflammation around lymphatics
  • May have trophoblastic differentiation with hCG+ cells
  • Commonly has squamous metaplasia

Well differentiated (FIGO grade 1)
  • Extensive, complex epithelial growth pattern with little intervening stroma
  • Usually budding and branching of large glands causing papillary structures
  • May be villoglandular on low power
  • May have true papillae (DD: clear cell carcinoma, serous carcinoma), but without atypia
  • Mild to moderate atypia is allowed or only focal; if atypia is more severe, FIGO grade is increased to moderate (FIGO grade 2)
  • Some are myoinvasive
  • Often has benign squamous differentiation (adenoacanthoma), focal mucinous, secretory or ciliated features
  • Usually stage 1, with 95% relapse free survival rate

Moderately differentiated (FIGO grade 2)
  • 6% - 50% of nonsquamous tumor is composed of sheet-like tumor cells without glandular features
  • Tumor cells have moderate pleomorphism, prominent nucleoli

Poorly differentiated (FIGO grade 3)
  • > 50% of nonsquamous tumor is composed of sheet-like tumor cells without glandular features
  • Tumor cells have high grade features
  • Glands poorly formed when present
  • May contain malignant squamous cells
  • Angiolymphatic invasion common
Microscopic (histologic) images
Scroll to see all images.

Corded and hyalinizing pattern - Case #294:

Endometrial biopsy

Total abdominal hysterectomy

Well differentiated tumors:

Glands lack cytologic atypia

Masses of glands with different patterns

A confluent glandular pattern is present

Glands show atypia, but are still separated by wisps of stroma

Desmoplastic or scirrhous
stromal response of
invasive carcinoma

Foam cells are seen centrally

These illustrations show small, round, regular glands growing in a confluent pattern

Confluent glands lined predominantly
by a single row of cells with large,
round, normochromatic nuclei

Moderately differentiated tumors:

Solid sheets of tumor cells are seen in addition to glands

Anisonucleosis, prominent nucleoli and nuclear clearing

Poorly differentiated tumors:

Adenocarcinoma of endometrioid type

Malignant glands at the center

Images hosted on other servers:

Moderately differentiated tumors:

Visible in this illustration are confluent glands lined
predominantly by a single row of cells with large,
round, normochromatic nuclei that are somewhat
variable in size and irregularly distributed

Poorly differentiated tumors:

Solid tumor masses infiltrating the myometrium

Solid tumor mass with several mitotic figures

Partly solid and partly gland
forming tumor masses infil-
trating the myometrium


With leiomyosarcoma #1, #2

Cytology images

Images hosted on PathOut server:

Endometrial aspirate of well differentiated tumor

aspirate of poorly
differentiated tumor

Electron microscopy images

Images hosted on PathOut server:

Fairly pleo-
morphic nuclei
with noteworthy

Numerous lysosomes,
prominent free ribosomes,
lipid vacuoles

Differential diagnosis
  • Ciliary metaplasia
  • Papillary change
  • Progesterone treatment related changes
  • Shedding endometrium with papillary syncytial metaplasia
  • Villoglandular endometrioid carcinoma
  • Well differentiated tumors: atypical hyperplasia / EIN (Mod Pathol 2000;13:309)
  • Poorly differentiated tumors: serous carcinoma
Additional references
Back to top