Ovary
Endometrioid tumors
Endometrioid carcinoma

Editorial Board Member: Gulisa Turashvili, M.D., Ph.D.
Deputy Editor-in-Chief: Jennifer A. Bennett, M.D.
Ozlen Saglam, M.D.

Topic Completed: 16 February 2021

Minor changes: 22 February 2021

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PubMed search: Ovarian endometrioid carcinoma [TI]

Ozlen Saglam, M.D.
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Cite this page: Saglam O. Endometrioid carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/ovarytumorendometrioidcarcinoma.html. Accessed April 17th, 2021.
Definition / general
  • Ovarian carcinoma resembling endometrioid adenocarcinoma of the endometrium
Essential features
  • Most common ovarian endometrioid tumor
  • Usually low grade and diagnosed at early stages
  • May be associated with endometriosis and adenofibroma
Terminology
  • Seromucinous carcinoma is included as a subtype of endometrioid ovarian carcinoma in the 2020 WHO blue book for female genital tumors
ICD coding
  • ICD-11: 2C73.01 - endometrioid adenocarcinoma of ovary
Epidemiology
Sites
  • Ovaries
Pathophysiology
  • Most common molecular alterations: WNT / beta catenin signaling pathway (CTNNB1 - 53%), PI3K pathway (PIK3CA - 40% and PTEN - 17%) (Mod Pathol 2014;27:128)
Etiology
  • Unknown
Clinical features
  • Most common symptoms are abdominal distention and pain
  • Background endometriosis is not associated with survival (J Gynecol Oncol 2018;29:e18)
Laboratory
Radiology description
Prognostic factors
Case reports
Treatment
  • Surgery for early stage cancers
  • Adjuvant chemotherapy is associated with survival benefit for patients with inadequately staged and grade 2 stage I cancers (Gynecol Oncol 2020;156:315)
  • Patients with advanced stage disease (FIGO III and IV) might benefit from platinum based chemotherapy (Future Oncol 2018;14:123)
Gross description
  • Usually unilateral; only 5% bilateral
  • Cystic with solid component and areas of hemorrhage
  • With or without polypoid nodule in endometriotic cyst
  • Mean tumor size: 11 cm (range: 3 - 22 cm)
  • Reference: Arch Gynecol Obstet 2008;278:209
Gross images

AFIP images
Surface of ovary and opened uterus

Ovary and uterus with tumor

Arising in endometriotic cyst

Tumor arising in endometriotic cyst



Contributed by Ayse Ayhan, M.D.
Bilateral endometrioid cancer, left: 730g, 14.5x12.6cm

Smooth ovarian capsule

Bilateral endometrioid cancer, left: 730g, 14.5x12.6cm

Multiple papillary excrescences

Bilateral endometrioid cancer, left: 730g, 14.5x12.6cm

Papillary / nodular solid component

Partially opened cyst wall

Partially opened cyst wall

Cyst wall outer surface

Cyst wall outer surface

Solid / papillary areas

Solid / papillary areas


Serial sections

Serial sections

Cross section

Cross section

Outer aspect

Outer aspect

Partially opened cyst wall

Partially opened cyst wall

Fixation

Fixation

Ovarian mass lesion

Ovarian mass lesion

Frozen section description
  • Depending on histologic grade, a combination of glandular and solid areas may be seen
  • Squamous differentiation may be present
  • Differential diagnosis depends on histologic grade but includes metastatic carcinoma, well differentiated Sertoli-Leydig cell tumor and serous carcinoma (Arch Pathol Lab Med 2019;143:47)
Frozen section images

Contributed by Ozlen Saglam, M.D.
Endometrioid carcinoma with papillary architecture

Endometrioid carcinoma with papillary architecture

Low grade nuclear features

Low grade nuclear features

Microscopic (histologic) description
  • Most common morphologic pattern is confluent (back to back) glands
  • Stromal invasion is usually by expansion; rarely, destructive stromal invasion can be observed
  • Squamous metaplasia (morules or keratin pearls), cytoplasmic mucin, intracytoplasmic vacuoles, oncocytic changes, clear cell changes and cilia and sex cord-like elements (sertoliform) can be observed; none of these morphologic features affect the histologic grade (Am J Surg Pathol 2007;31:1203)
  • Histologic grading: same as for endometrial endometrioid adenocarcinoma
    • FIGO grade 1: less than 5% solid component
    • FIGO grade 2: 6 - 50% solid component
    • FIGO grade 3: more than 50% solid component
  • Endometriosis or adenofibroma may be present in the background
  • Vascular invasion is rare
  • Might be associated with serous, undifferentiated carcinoma and yolk sac tumor (mixed carcinoma) (Am J Surg Pathol 1994;18:687, Am J Surg Pathol 1996;20:1056)
  • Morphologic features in favor of synchronous endometrial and ovarian tumors:
    • Both tumors are low grade
    • No myometrial invasion or less than 50% myometrial inivasion
    • There is no involvement in any other anatomical sites
    • No lymphovascular involvement in either tumor
    • Background atypical endometrial hyperplasia in the endometrium
    • Unilateral ovarian involvement and unifocal parenchymal distribution of tumor
    • Lack of ovarian capsular, multifocal or hilar involvement
    • Presence of endometriosis or adenofibroma in the ovary (Int J Gynecol Pathol 2019;38:S75)
Microscopic (histologic) images

Contributed by Ozlen Saglam, M.D.
Endometrioid adenocarcinoma, FIGO grade 1

Endometrioid adenocarcinoma, FIGO grade 1

Endometrioid adenocarcinoma, FIGO grade 2

Endometrioid adenocarcinoma, FIGO grade 2

Endometrioid adenocarcinoma, FIGO grade 3

Endometrioid adenocarcinoma, FIGO grade 3

Areas with squamous differentiation

Squamous differentiation

Peritoneal keratin granuloma

Peritoneal keratin granuloma

Ciliated cells

Ciliated cells


Secretory cells

Secretory change

Oncocytic cells

Oncocytic cells

Spindle cells

Spindle variant

Trabecular pattern resembling sex cord stromal tumor

Trabecular pattern
resembling sex
cord stromal tumor

Endometrioid cancer and background adenofibroma

Endometrioid carcinoma and background adenofibroma

Atypical / papillary endometriosis

Endometriosis



Contributed by Sakinah A Thiryayi, M.D. and Gulisa Turashvili, M.D., Ph.D. (Case #500)
Glandular architecture

Glandular architecture

Back to back glands

Back to back glands

Low grade cytology

Low grade cytology

Cellular intervening stroma

Cellular intervening stroma


Plump stromal cells

Plump stromal cells

Inhibin

Inhibin

p53

p53

Virtual slides

Images hosted on other servers:
Background endometriosis

FIGO grade 1, background endometriosis

Cytology description
  • Large cohesive cell clusters
  • Mild nuclear membrane irregularities
  • May see squamous differentiation
  • Detection in pelvic washing: sensitivity 58%, specificity 89% Cancer 2004;102:150
Positive stains
Negative stains
Molecular / cytogenetics description
  • Ovarian endometrioid cancers and associated endometriosis share mutations in majority of cases (85 - 90%) (J Pathol 2018;245:265)
  • CTNNB1 (53%), PIK3CA (40%), KRAS (33%), ARID1A (30%) and PTEN (17%) are common mutations (Cancer Cell 2007;11:321, Mod Pathol 2014;27:128)
  • The Cancer Genome Atlas (TCGA) molecular classifiers for endometrial carcinoma has categorized ovarian endometrioid carcinoma into prognostically significant groups (Mod Pathol 2017;30:1748)
Sample pathology report
  • Left ovary and fallopian tube, salpingo-oophorectomy:
    • Endometrioid adenocarcinoma, FIGO grade 1 (see synoptic report)
    • Tumor size: 8.5 cm
    • Ovarian surface: not involved by carcinoma
    • Fallopian tube: not involved by carcinoma
    • Additional findings: background endometriotic cyst
Differential diagnosis
Board review style question #1

A 48 year old woman with endometrial carcinoma underwent laparoscopic staging procedure and a right ovarian adenocarcinoma was identified. Endometrial and ovarian lesions have identical morphology (see image). The ovarian lesion is confined to the right ovary and endometrial cancer has superficial myometrial invasion. Which immunostain can be useful to rule out metastatic endometrial adenocarcinoma?

  1. Immunostains are not contributory in differential diagnosis
  2. Napsin A
  3. PAX8
  4. Vimentin
  5. WT1
Board review style answer #1
A. Immunostains are not contributory in a differential diagnosis

Comment Here

Reference: Endometrioid carcinoma
Board review style question #2
Which of the following is associated with favorable disease outcome in patients with ovarian endometrioid carcinoma?

  1. Strong PAX8 expression
  2. WT1 expression
  3. Vimentin expression
  4. Cytoplasmic napsin A expression
  5. Low grade tumor and nuclear beta catenin expression
Board review style answer #2
E. Low grade tumor and nuclear beta catenin expression

Comment Here

Reference: Endometrioid carcinoma
Board review style question #3
What clinical manifestations have most commonly been associated with functioning stroma in ovarian tumors?

  1. Adrenergic manifestations
  2. Androgenic manifestations
  3. Estrogenic manifestations
  4. Progestogenic manifestations
Board review style answer #3
C. Estrogenic manifestations

Comment Here

Reference: Endometrioid carcinoma
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