Intermediate trophoblast


Image:Intermediate trophoblast - high mag.jpg|thumb|right|Micrograph showing intermediate trophoblasts. H&E stain.
[Image:Intermediate trophoblast - lmwk - high mag.jpg|thumb|right|Implantation site intermediate trophoblast. Low molecular weight cytokeratin stain.]
Intermediate trophoblast is a distinct subtype of trophoblastic tissue that arises from the cytotrophoblast.
It is sub-categorized by location:
  • Villous intermediate trophoblast:
  • *at anchoring villi of trophoblastic column
  • Implantation site intermediate trophoblast:
  • *at implantation site, differentiated from villous intermediate trophoblast
  • Chorionic-type intermediate trophoblast
  • *at chorionic laeve of fetal membrane, differentiated from villous intermediate trophoblast

Function

The function of the implantation site intermediate trophoblast is to anchor the placenta to the maternal tissue.

Histomorphology

  • Villous intermediate trophoblast
  • * polyhedral and uniform nuclei
  • * prominent cell border; abundant eosinophilic to clear cytoplasm
  • * cohesive growth
  • Implantation site intermediate trophoblast
  • * pleomorphic irregular nuclei, large and hyperchromatic, may show multinucleation
  • * abundant eosinophilic to amphophilic cytoplasm
  • * infiltrative growth
  • Chorionic-type intermediate trophoblast
  • * round to polyhedral nuclei, may multinucleation
  • * abundant eosinophilic to clear cytoplasm
  • * cohesive growth

Pathology

Intermediate trophoblasts are thought to be the cell of origin for: