Difference between revisions of "Odontogenic tumours and cysts"

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The general topic of ''head and neck pathology'' is covered in the ''[[head and neck pathology]]'' and ''[[head and neck cytopathology]]'' articles.  
The general topic of ''head and neck pathology'' is covered in the ''[[head and neck pathology]]'' and ''[[head and neck cytopathology]]'' articles.  
==Tooth histiology 101==
Teeth develop from a combination of:
#Epithelium (downward growth).
#Mesenchyme.
==Enamel 101==
*Arises from ''reduced enamel epithelium''.
===Reduced enamel epithelium===
====Microscopic====
Features:
*Bilayered epithelium consisting of:
**Cuboidal/columnar cells with:
***Moderate eosinophilic cytoplasm.
***Round (slightly irregular) centrally place nuclei.
Notes:
*Transforms into squamous epithelium. (???)


==Radicular cyst==
==Radicular cyst==
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*Keratinized epithelium: think keratocytic odontogenic tumour.
*Keratinized epithelium: think keratocytic odontogenic tumour.


===Dentigerous cyst==
===Dentigerous cyst===
===Clinical===
===Clinical===
*Unerupted tooth - usually wisdom teeth.
*Unerupted tooth - usually wisdom teeth.
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===General===
===General===
*Osteous lesion.
*Osteous lesion.
===Classification===
Location:
#Intra-osseous.
#*Locally aggressive.
#Peripheral.
#*Benign.
====Subclassification of intra-osseous type====
Histology:
#Solid/multicystic.
#*More commonly reoccur.
#Unicystic.
#*Unlikely to reoccur.
#*Classically found in younger individuals.


===Microscopic===
===Microscopic===
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*Stellate reticulum - star-shaped cells, found in a developing tooth.<ref>URL: [http://en.wikipedia.org/wiki/Stellate_reticulum http://en.wikipedia.org/wiki/Stellate_reticulum]. Accessed on: March 9, 2010.</ref>
*Stellate reticulum - star-shaped cells, found in a developing tooth.<ref>URL: [http://en.wikipedia.org/wiki/Stellate_reticulum http://en.wikipedia.org/wiki/Stellate_reticulum]. Accessed on: March 9, 2010.</ref>
*Tall columnar cells.
*Tall columnar cells.
**Nuclei distant from the basement membrane (reverse polarization of the nuclei).
**Palisaded nuclei with reverse polarization.
***Reverse polarization of nuclei = nuclei distant from the basement membrane/nuclei at pole opposite of basement membrane.
***Palisaded nuclei = picket fence appearance; columnar-shaped nuclei with long axis aligned perpendicular to the basement membrane -- '''key feature'''.
**Subnuclear vacuolization.
*+/-Giant cells.
*+/-Giant cells.


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*[http://www.cytochemistry.net/microanatomy/digestive/devtooth9.jpg Stellate reticulum (cytochemistry.net)].
*[http://www.cytochemistry.net/microanatomy/digestive/devtooth9.jpg Stellate reticulum (cytochemistry.net)].


==Odontogenic myxoma==
===General===
*Benign tumour of mesenchymal origin.
*Often reoccurs.
*Radiologic DDx includes ameloblastoma.
===Gross===
*Gelatinous mass.
===Microscopic===
Features:
*Paucicellular lesion with pale staining.


==See also==
==See also==

Revision as of 03:05, 14 September 2010

This article covers odontogenic tumours and cysts, which is a subset of oral pathology and can be grouped under the heading of head and neck pathology.

The general topic of head and neck pathology is covered in the head and neck pathology and head and neck cytopathology articles.

Tooth histiology 101

Teeth develop from a combination of:

  1. Epithelium (downward growth).
  2. Mesenchyme.

Enamel 101

  • Arises from reduced enamel epithelium.

Reduced enamel epithelium

Microscopic

Features:

  • Bilayered epithelium consisting of:
    • Cuboidal/columnar cells with:
      • Moderate eosinophilic cytoplasm.
      • Round (slightly irregular) centrally place nuclei.

Notes:

  • Transforms into squamous epithelium. (???)

Radicular cyst

  • AKA periapical cyst.

Clinical

  • Non-vital tooth - key feature.
    • The tooth that has lost its nerve.

Microscopic

Features:

  • Squamous epithelium - always non-keratinized.
  • +/-Giant cells.
  • +/-Cholesterol clefts.

DDx:

  • Dentigerous cyst (history is the key to differentiate).

Notes:

  • Keratinized epithelium: think keratocytic odontogenic tumour.

Dentigerous cyst

Clinical

  • Unerupted tooth - usually wisdom teeth.
    • Young adults.

Gross

  • Lesion at crown of tooth.

Microscopic

Features:

  • Squamous epithelium - always non-keratinized.
  • +/-Giant cells.
  • +/-Cholesterol clefts.

DDx:

  • Radicular cyst (history is the key to differentiate).

Notes:

  • Keratinized epithelium: think keratocytic odontogenic tumour.

Keratocystic odontogenic tumour

General

Clinical

Features:[2]

  • Most common presentation: swelling.
  • Location: usually mandible.
  • May mimic ameloblastoma radiologically.

Microscopic

Features: [3]

  • Stratified epithelium resembling squamous epithelium -- but:
    • Lacks rete ridges.
    • Artefactual separation of epithelium from the basement membrane.

DDx:

  • Odontogenic cyst.

Images:

Ameloblastoma

General

  • Osteous lesion.

Classification

Location:

  1. Intra-osseous.
    • Locally aggressive.
  2. Peripheral.
    • Benign.

Subclassification of intra-osseous type

Histology:

  1. Solid/multicystic.
    • More commonly reoccur.
  2. Unicystic.
    • Unlikely to reoccur.
    • Classically found in younger individuals.

Microscopic

Features:[4]

  • Stellate reticulum - star-shaped cells, found in a developing tooth.[5]
  • Tall columnar cells.
    • Palisaded nuclei with reverse polarization.
      • Reverse polarization of nuclei = nuclei distant from the basement membrane/nuclei at pole opposite of basement membrane.
      • Palisaded nuclei = picket fence appearance; columnar-shaped nuclei with long axis aligned perpendicular to the basement membrane -- key feature.
    • Subnuclear vacuolization.
  • +/-Giant cells.

Images:

Odontogenic myxoma

General

  • Benign tumour of mesenchymal origin.
  • Often reoccurs.
  • Radiologic DDx includes ameloblastoma.

Gross

  • Gelatinous mass.

Microscopic

Features:

  • Paucicellular lesion with pale staining.

See also

References

  1. Madras, J.; Lapointe, H. (Mar 2008). "Keratocystic odontogenic tumour: reclassification of the odontogenic keratocyst from cyst to tumour.". J Can Dent Assoc 74 (2): 165-165h. PMID 18353202.
  2. Habibi, A.; Saghravanian, N.; Habibi, M.; Mellati, E.; Habibi, M. (Sep 2007). "Keratocystic odontogenic tumor: a 10-year retrospective study of 83 cases in an Iranian population.". J Oral Sci 49 (3): 229-35. PMID 17928730.
  3. Thompson LDR. Head and neck pathology - (Foundations in diagnostic pathology). Goldblum JR, Ed.. Churchill Livingstone. 2006. ISBN 0-443-06960-3.
  4. URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970616-7. Accessed on: March 9, 2010.
  5. URL: http://en.wikipedia.org/wiki/Stellate_reticulum. Accessed on: March 9, 2010.