Difference between revisions of "Trophoblast"

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**Single uniform nucleus.
**Single uniform nucleus.


===Implantation site===
 
*Intermediate trophoblast.
==Intermediate trophoblast==
===General===
*Found at implantation site.
 
*Thought to be the cell of origin for:<ref name=pmid11192071>{{cite journal |author=Shih IM, Kurman RJ |title=The pathology of intermediate trophoblastic tumors and tumor-like lesions |journal=Int. J. Gynecol. Pathol. |volume=20 |issue=1 |pages=31–47 |year=2001 |month=January |pmid=11192071 |doi= |url=}}</ref>
**Exaggerated placental site (EPS).
**Placental site nodule (PSN).
**Placental site trophoblastic tumor (PSTT).
**Epithelioid trophoblastic tumor (ETT).
 
===Microscopic===
Features:
*Large cells.
*Eosinophilic cytoplasm.
**May be multi-nucleated.


====IHC====
====IHC====

Revision as of 16:17, 22 July 2010

Chorionic villi are part of a normal pregnancy. They are derived from the conceptus, i.e. NOT maternal.

Tumours arising from the trophoblast are dealt with in gestational trophoblastic disease.

Chorionic villi 101

  • Maternal blood is around villi.
  • Fetal blood (nucleated (fetal) RBCs) in the villi.

Basic histology

  • Outer layer of villus: syncytiotrophoblasts.
  • Beneath syncytiotrophoblast (and closer to fetus) cytotrophoblasts.

Chorionic villi 102

  • Syncytiotrophoblasts (eosinophilic cytoplasm with vacuoles (contain hCG), multiple hyperchromatic nuclei).
    • Large + many irreg. or lobular hyperchromatic nuclei.
    • Eosinophilic vacuolated cytoplasm (contains hCG).
    • Closest to mom - covers cytotrophoblast.[1]
  • Cytotrophoblasts (polygonal shape, distinct borders, clear cytoplasm, in cords, single nucleus).
    • Polygonal shaped cells in cords/masses.
    • Distinct cell borders.
    • Covered by syncytiobrophoblast[2] - closer to fetus than syncytiotrophoblasts.
    • Clear cytoplasm.
    • Single uniform nucleus.


Intermediate trophoblast

General

  • Found at implantation site.
  • Thought to be the cell of origin for:[3]
    • Exaggerated placental site (EPS).
    • Placental site nodule (PSN).
    • Placental site trophoblastic tumor (PSTT).
    • Epithelioid trophoblastic tumor (ETT).

Microscopic

Features:

  • Large cells.
  • Eosinophilic cytoplasm.
    • May be multi-nucleated.

IHC

Features:[4]

  • hPL (human placental lactogen) +ve.
  • beta-hCG -ve.
  • Keratin +ve.
  • EMA +ve in 2nd & 3rd trimester.

Notes:

  • Cytotrophoblast and syncytiotrophoblast - keratin +ve.[4]

Age of villi

Young villi

Old villi

  • Blood vessels present and at the periphery of villus - contain nucleated (fetal) RBCs.
  • Syncytial knots.

See also

References

  1. http://upload.wikimedia.org/wikipedia/commons/4/45/Gray37.png
  2. http://upload.wikimedia.org/wikipedia/commons/4/45/Gray37.png
  3. Shih IM, Kurman RJ (January 2001). "The pathology of intermediate trophoblastic tumors and tumor-like lesions". Int. J. Gynecol. Pathol. 20 (1): 31–47. PMID 11192071.
  4. 4.0 4.1 Yeh IT, O'Connor DM, Kurman RJ (May 1990). "Intermediate trophoblast: further immunocytochemical characterization". Mod. Pathol. 3 (3): 282–7. PMID 1694585.