Endometrioid tumors

Endometrioid cystadenoma and adenofibroma

Editorial Board Member: Gulisa Turashvili, M.D., Ph.D.
Deputy Editor-in-Chief: Jennifer A. Bennett, M.D.
Stephanie L. Skala, M.D.

Last author update: 3 August 2022
Last staff update: 24 December 2022

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PubMed Search: Ovary endometrioid cystadenoma / adenofibroma

Stephanie L. Skala, M.D.
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Cite this page: Skala SL. Endometrioid cystadenoma and adenofibroma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/ovarytumorendometadenofibroma.html. Accessed February 23rd, 2024.
Definition / general
  • Benign tumors with endometrioid type glands, sometimes associated with endometriosis
Essential features
  • Benign biphasic tumor with endometrioid type glands and fibromatous stroma
  • Sometimes associated with endometriosis
  • Squamous or mucinous metaplasia or dystrophic stromal calcifications can be seen
ICD coding
  • ICD-O:
    • 8380/0 - endometrioid cystadenoma, NOS
    • 8381/0 - endometrioid adenofibroma, NOS
  • ICD-11:
    • 2F32.Y & XH1CX5 - other specified benign neoplasm of ovary & endometrioid adenofibroma, NOS
  • Ovary
  • In some cases, endometrioid cystadenomas may represent endometriotic cysts without obvious endometrial type stroma
  • Unknown
Clinical features
  • Detected on pelvic imaging (ultrasound, CT, MRI)
  • Cystectomy / oophorectomy
Radiology description
Prognostic factors
  • These tumors are benign
Case reports
  • Not applicable; these tumors are benign
Gross description
  • Cystadenoma: usually unilocular cyst
  • Adenofibroma: firm, white nodule with honeycomb appearance to cut surface, sometimes in the wall of an endometriotic cyst (J Obstet Gynaecol 2011;31:352)
Gross images

AFIP images
With endometriosis

With endometriosis

Microscopic (histologic) description
  • Cystadenoma:
    • Cyst lined by benign endometrioid epithelium without endometrial stroma
    • Endometriosis may be present
  • Adenofibroma:
    • Widely spaced benign endometrioid glands associated with fibromatous stroma
    • Endometriosis may be present
  • Areas of mucinous or serous differentiation can be seen (Histopathology 2021;78:445)
Microscopic (histologic) images

Contributed by Stephanie L. Skala, M.D.
Variably dilated endometrioid glands

Variably dilated endometrioid glands

Endometrioid glands, some ciliated

Endometrioid glands, some ciliated

Predominantly cystic neoplasm

Predominantly cystic neoplasm

Attenuated cyst lining

Attenuated cyst lining

Virtual slides

Images hosted on other servers:

Cystic ovarian tumor

Cytology description
  • Bland endometrioid cells (epithelial cells with moderate amounts of cytoplasm and bland, eccentrically placed nuclei) and fragments of ovarian type stroma (Diagn Cytopathol 2004 Jul;31:38)
Positive stains
Negative stains
Sample pathology report
  • Ovary, right, oophorectomy:
    • Right ovary with endometrioid adenofibroma arising in a background of endometriosis
Differential diagnosis
  • Endometriosis:
    • Has associated endometrial type stroma with or without hemosiderin laden macrophages
  • Serous cystadenoma / adenofibroma:
    • Glands show only tubal type differentiation
    • WT1, ER diffusely positive
    • Membranous beta catenin staining
  • Seromucinous cystadenoma:
    • Glands show admixture of Müllerian epithelia with bland cytological features
      • Ciliated, endocervical type, mucinous, endometrioid (which may have squamous or mucinous differentiation)
    • Also associated with endometriosis
    • Some authors believe that a subset of seromucinous cystadenomas represent benign endometrioid neoplasms with foci of mucinous or serous differentiation (Histopathology 2021;78:445)
Board review style question #1

The image above shows a representative section of a 6 cm, solid and cystic ovarian mass. What is the diagnosis?

  1. Endometrioid adenofibroma
  2. Endometrioid borderline tumor
  3. Endometrioid carcinoma
  4. Endometriosis
  5. Fibroma
Board review style answer #1
A. Endometrioid adenofibroma

Comment Here

Reference: Endometrioid cystadenoma / adenofibroma
Board review style question #2
What feature distinguishes endometrioid cystadenoma / adenofibroma from endometriosis?

  1. Absence of endometrial type stroma
  2. Epithelial lining
  3. Location
  4. Mucinous differentiation
  5. Size
Board review style answer #2
A. Absence of endometrial type stroma

Comment Here

Reference: Endometrioid cystadenoma / adenofibroma
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