Difference between revisions of "Trophoblast"

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(→‎Trophoblast table: +age of villi table)
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==Villi and age - table==
==Villi and age - table==
{| class="wikitable"
{| class="wikitable"
| Gestational age
| '''Gestational age'''
| Nucleated RBCs
| '''Nucleated [[RBC]]s'''
| Cytotrophoblast / syncytiotrophoblast
| '''Cytotrophoblast / <br>syncytiotrophoblast'''
| Villi size
| '''Villi size'''
| Vessels
| '''Vessels'''
| '''Other'''
|-
|-
| First trimester
| First trimester
Line 141: Line 142:
| large
| large
| few; location central
| few; location central
|
|-
|-
| Second trimester
| Second trimester
| rare
| rare
| cytotrophoblast difficult to identify
| cytotrophoblast difficult to identify; syncytial knots uncommon
| intermediate
| intermediate
| intermediate; location: central/periphery
| intermediate; location: central/periphery
|
|-
|-
| Third trimester
| Third trimester
| absent
| absent
| cytotrophoblast indistinct
| cytotrophoblast indistinct; syncytial knots common
| small
| small
| abundant; location: periphery of villi
| abundant; location: periphery of villi
| focal calcifications
|}
|}



Revision as of 14:19, 8 February 2011

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 / closer to mother : syncytiotrophoblasts.
  • Inner layer of villus / 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

  • Abbreviated: IT.
  • 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).

Subtypes

Three subtypes of IT are recognized:[3]

  1. Implanation site IT.
  2. Villous IT.
  3. Chorionic-type IT.

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.

Trophoblast table

Based on Shih et al.:[3]

Cytotrophoblast Syncytiotrophoblast Villous intermediate
trophoblast
Implanation site
intermediate trophoblast
Chorionic-type
intermediate trophoblast
Nuclear features round, small multinucleated polyhedral pleomorphic +/-multinucleation
(occasional), +/-nucleoli
round / polyhedral
Cell borders well-defined poorly defined (?) well-defined moderately-defined poorly defined (?)
Cytoplasm minimal, clear to granular abundant, vacuolated abundant & eosinophilic to clear abundant & eosinophilic abundant & eosinophilic
Location villi - deep to
syncytiotrophoblast
villi - superficial to
cytotrophoblast -
nearest to maternal blood
villi implanatation site chorion
Function stem cell produces hormones ??? anchor placenta ???
IHC beta-hCG ??? beta-hCG ??? inhibin+, hPL+, beta-hCG-[4] ???
Image [1]

hPL = human placental lactogen.

Notes:

  • Keratin is positive in all trophoblastic tissue and negative in decidual tissue.[4]

Villi and age - table

Gestational age Nucleated RBCs Cytotrophoblast /
syncytiotrophoblast
Villi size Vessels Other
First trimester present both can be identified large few; location central
Second trimester rare cytotrophoblast difficult to identify; syncytial knots uncommon intermediate intermediate; location: central/periphery
Third trimester absent cytotrophoblast indistinct; syncytial knots common small abundant; location: periphery of villi focal calcifications

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. 3.0 3.1 3.2 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 4.2 4.3 Yeh IT, O'Connor DM, Kurman RJ (May 1990). "Intermediate trophoblast: further immunocytochemical characterization". Mod. Pathol. 3 (3): 282–7. PMID 1694585.