Difference between revisions of "Trophoblast"

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| '''Cytotrophoblast'''
| '''Cytotrophoblast'''
| '''Syncytiotrophoblast'''
| '''Syncytiotrophoblast'''
| '''Villous IT'''
| '''Villous intermediate<br>trophoblast'''
| '''Implanation site IT'''
| '''Implanation site<br>intermediate trophoblast'''
| '''Chorionic-type IT'''
| '''Chorionic-type<br>intermediate trophoblast'''
|-
|-
| Nuclear features
| Nuclear features
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| multinucleated
| multinucleated
| polyhedral
| polyhedral
| pleomorphic +/-multinucleation
| pleomorphic +/-multinucleation <br>(occasional), +/-nucleoli
| round/polyhedral
| round/polyhedral
|-
|-

Revision as of 14:18, 27 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

  • 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 poorly defined poorly defined
Cytoplasm minimal, clear to granular abundant, vacuolated abundant & eosinophilic to clear abundant & eosinophilic abundant & eosinophilic
IHC beta-hCG ??? beta-hCG ??? LMWK, inhibin ???
Image [1]

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