Non tumor
Pregnancy related changes

Topic Completed: 1 September 2011

Minor changes: 15 October 2019

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PubMed search: pregnancy-related changes uterus

Nat Pernick, M.D.
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Cite this page: Pernick N. Pregnancy related changes. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/uteruspregnancy.html. Accessed May 26th, 2020.
Definition / general
  • These changes are similar with intrauterine pregnancy, ectopic pregnancy and progesterone therapy
  • See also Arias-Stella reaction
  • Maternal portion of placenta composed of endometrial lining during pregnancy; due to influence of progesterone (Wikipedia)
  • Cells are highly characteristic: sheets of large polygonal cells with abundant cytoplasm, minimal atypia
Gestational hyperplasia
  • Gross description: lush decidua, placental fragments, gestational sac
  • Micro description: early - prominent glandular secretion, stromal edema and predecidual reaction, all simultaneous; implies fertilized ovum has implanted; later changes - glands are tubular, not coiled
  • Glandular cells may have inclusion-like cleared chromatin resembling HSV infection, due to replacement of chromatin by fine filamentous network that is immunoreactive for biotin (J Clin Pathol 1997;50:153); may see intermediate trophoblasts or villi
  • DD: late secretory changes in cycling endometrium
Placental site nodules
  • Also called implantation site reaction
  • Uncommon; benign; usually regresses after delivery or abortion (Indian J Pathol Microbiol 2009;52:240)
  • Micro description: numerous chorionic-type extravillous (intermediate) trophoblasts with large, atypical nuclei arranged in a syncytium, often with mitotic figures that may invade blood vessels (to keep them patent during pregnancy); also cytotrophoblasts and syncytiotrophoblasts, chronic inflammatory cells
  • Positive stains: hPL (intermediate trophoblasts), hCG (syncytiotrophoblasts, cytotrophoblasts), keratin
  • Differential diagnosis:
Gross images

Images hosted on other servers:

Fetus within uterus

Microscopic (histologic) images

Images hosted on other servers:

Decidua: various images

Gestational endometrium: various images

Placental site nodule: various images

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