Ovary

Other nonneoplastic lesions

Ectopic decidual reaction



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PubMed Search: Ectopic decidual reaction

Aurelia Busca, M.D., Ph.D.
Carlos Parra-Herran, M.D.
Page views in 2024 to date: 1,873
Cite this page: Busca A, Parra-Herran C. Ectopic decidual reaction. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/ovarynontumorectopicdecidual.html. Accessed April 14th, 2024.
Definition / general
  • Presence of ectopic decidualized uterine stromal cells in the ovary
Essential features
  • Presence of ectopic decidualized uterine stromal cells in the ovary
  • Usually an incidental finding associated with pregnancy
  • Typically transient, will regress 4 - 6 weeks postpartum
Terminology
  • Ectopic decidua or ovarian deciduosis
Epidemiology
  • Associated with pregnancy
  • In a study of 307 consecutive caesarean sections, macroscopic deciduosis was found in 31 (10.1%) cases (Eur J Obstet Gynecol Reprod Biol 2016;197:54)
  • Can also develop as a result of exogenous progesterone effect
Sites
  • Ectopic decidua have been described in the cervix, ovary and fallopian tube; also peritoneal surface, appendix, bladder, small and large intestine, mesentery, lymph nodes
Pathophysiology
Diagnosis
  • Often an incidental finding in surgical specimens or a discrete nodule / mass discovered during caesarean section
Radiology description
Case reports
Treatment
  • Benign entity, no further treatment necessary; usually regresses 4 - 6 weeks postpartum
  • If mass forming and showing worrisome features for malignancy on imaging, the lesion is excised to establish the correct diagnosis
  • Reference: Case Rep Obstet Gynecol 2015;2015:217367
Clinical images

Images hosted on other servers:
Macroscopic appearance

Macroscopic appearance

Microscopic (histologic) description
  • Large polygonal cells with abundant eosinophilic cytoplasm, bland nuclei and visible nucleoli
  • No glands present (to differentiate it from decidualized endometriosis)
  • Reference: Case Rep Obstet Gynecol 2015;2015:217367
Microscopic (histologic) images

Contributed by Aurelia Busca, M.D., Ph.D.
Deciduosis of ovarian stroma

Deciduosis of ovarian stroma

Areas of deciduosis

Areas of deciduosis

Ovarian surface adhesions with deciduosis Ovarian surface adhesions with deciduosis

Ovarian surface adhesions with deciduosis


Ovarian surface adhesions with deciduosis Ovarian surface adhesions with deciduosis

Ovarian surface adhesions with deciduosis

Ovarian deciduosis in a patient on progestin therapy Ovarian deciduosis in a patient on progestin therapy

Ovarian deciduosis in a patient on progestin therapy

Negative stains
Sample pathology report
  • Ovary, oophorectomy:
    • Benign ovary with focal deciduosis
Differential diagnosis
  • Endometriosis:
  • Epithelial ovarian neoplasm when mass forming:
    • Histologic features are bland and mitotic activity is low in deciduosis
    • Absence of glands in deciduosis
    • Epithelial proliferation with variable atypia and architectural complexity in epithelial neoplasms
  • Peritoneal mesothelioma or peritoneal carcinomatosis when there is additional involvement of peritoneal surface:
    • Histologic features are bland in deciduosis; also, context of pregnancy is helpful
    • Increased atypia, proliferation and architectural complexity in carcinomatosis and mesothelioma
  • Metastatic squamous cell carcinoma with keratinization:
    • More atypical
    • Presence of necrosis
    • Mitotically active
    • Cytokeratin+
Board review style question #1

Which of the following is true about the ovarian change illustrated in the figure shown above?

  1. It is a malignant process
  2. It is only seen in the ovary
  3. It requires lymph node sampling and full staging for management
  4. More sampling is required to demonstrate the presence of glands
  5. Typically associated with pregnancy
Board review style answer #1
E. Typically associated with pregnancy. The image shows ovarian deciduosis, which is associated with pregnancy, is typically transient and resolves postpartum. Answer A is incorrect because ovarian deciduosis is a benign process typically associated with pregnancy. Answer D is incorrect because it consists of stromal tissue, without glands. Answer C is incorrect because it typically regresses after pregnancy and does not require treatment. Answer B is incorrect because deciduosis can be seen at other sites (cervix, peritoneal cavity, etc.).

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Reference: Ectopic decidual reaction
Board review style question #2
Which of the following is true about ovarian deciduosis?

  1. It can be mistaken for endometriosis
  2. It is CD10 negative by immunohistochemistry
  3. Presence of nuclear atypia indicates malignant potential
  4. Responds to chemotherapy
  5. Treatment includes resection with or without chemotherapy
Board review style answer #2
A. It can be mistaken for endometriosis with stromal decidualization but unlike endometriosis, it does not contain glands. Answer B is incorrect because both have CD10 positive stroma. Answers C, D and E are incorrect because ovarian deciduosis is a benign incidental process and does not require treatment.

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Reference: Ectopic decidual reaction
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