Odontogenic tumours and cysts

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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.

The vast majority of oral malignancies are squamous cell carcinoma. Common odontogenic cysts are dentigerous cysts, and radicular cysts.[1]

Tooth histology 101

Teeth develop from a combination of:

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

Identifying stuff

Pulp:

  • Paucicellular.
  • Pale staining.

Enamel:

  • Hyperchromatic (dark purple).
  • "Fish scale" appearance.

Image:

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. (???)

Specific entities

Odontoma

General

  • Usually diagnosed clinically.
  • Benign.
  • Most common odontogenic tumour - considered to be a hamartoma.[2]
  • Etiology unknown.[3]
  • Typically first two decades of life.

Classification:[2]

  • Compound odontoma - tooth-like structure.
  • Complex odontoma - disorganized mass of odontogenic tissues.

Microscopic

Features:[2]

  • Dentin.
  • Cementum.
  • Pulpal tissue.
  • Enamel - has a "fish-scale" appearance.
    • Usually lost during decalcificiation.

Images:

Radicular cyst

  • AKA periapical cyst.

Clinical

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

Microscopic

Features:

  • Squamous epithelium - non-keratinized - important.
  • +/-Giant cells.
  • +/-Cholesterol clefts.
  • +/-Abundant plasma cells.

DDx:

Dentigerous cyst

General

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

Treatment:

Gross

  • Lesion at crown of tooth.

Microscopic

Features:

  • Squamous epithelium.
    • Classically described as non-keratinized - in which case the diagnosis is straight forward - important.
    • Approximately half have keratin.[6]
  • +/-Giant cells.
  • +/-Cholesterol clefts.

DDx:

Images:

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Keratinized

MAXILLARY SINUS CYST, LEFT, EXCISION:
- ACANTHOTIC STRATIFIED SQUAMOUS EPITHELIUM WITH INFLAMMATION, COMPACT
KERATIN AND FOCAL PARAKERATOSIS -- CONSISTENT WITH DENTIGEROUS CYST WITH KERATIN.
- BENIGN BONE.
- NEGATIVE FOR ODONTOGENIC KERATOCYSTIC TUMOUR (ODONTOGENIC KERATOCYST).

Keratocystic odontogenic tumour

Ameloblastoma

Adenomatoid odontogenic tumour

General

  • Paedatric population, typically female.
  • Recurrences rare.[8]

Main clinical DDx:

Treatment:

  • Surgical enuclation.[8]

Gross

  • Usually maxilla.[8]

Microscopic

Features:

  • Palisaded nuclei.
  • Whorled epithelium.

Notes:

  • No stellate reticulum.

DDx:

Image

IHC

Features:[8]

  • CK5 +ve.
  • CK19 +ve.

Ameloblastic fibroma

General

  • Paedatric population.

Microscopic

Features:

  • Palisaded nuclei.
  • Fibrous stroma.

Notes:

  • No stellate reticulum.

DDx:

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. Eichhorn, W.; Wehrmann, M.; Blessmann, M.; Pohlenz, P.; Blake, F.; Schmelzle, R.; Heiland, M. (Apr 2010). "Metastases in odontogenic cysts: literature review and case presentation.". Oral Surg Oral Med Oral Pathol Oral Radiol Endod 109 (4): 582-6. doi:10.1016/j.tripleo.2009.11.013. PMID 20303056.
  2. 2.0 2.1 2.2 2.3 Nelson, BL.; Thompson, LD. (Dec 2010). "Compound odontoma.". Head Neck Pathol 4 (4): 290-1. doi:10.1007/s12105-010-0186-2. PMID 20533004.
  3. Yadav, M.; Godge, P.; Meghana, SM.; Kulkarni, SR. (Apr 2012). "Compound odontoma.". Contemp Clin Dent 3 (Suppl 1): S13-5. doi:10.4103/0976-237X.95095. PMID 22629054.
  4. Dhanrajani, PJ.; Abdulkarim, SA.. "Multiple myeloma presenting as a periapical lesion in the mandible.". Indian J Dent Res 8 (2): 58-61. PMID 9495138.
  5. Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 748. ISBN 978-1416031215.
  6. Yoshiura, K.; Higuchi, Y.; Araki, K.; Shinohara, M.; Kawazu, T.; Yuasa, K.; Tabata, O.; Kanda, S. (Jun 1997). "Morphologic analysis of odontogenic cysts with computed tomography.". Oral Surg Oral Med Oral Pathol Oral Radiol Endod 83 (6): 712-8. PMID 9195629.
  7. Moosvi, Z.; Tayaar, SA.; Kumar, GS. (Apr 2011). "Neoplastic potential of odontogenic cysts.". Contemp Clin Dent 2 (2): 106-9. doi:10.4103/0976-237X.83073. PMC 3180832. PMID 21957386. //www.ncbi.nlm.nih.gov/pmc/articles/PMC3180832/.
  8. 8.0 8.1 8.2 8.3 8.4 8.5 Handschel, JG.; Depprich, RA.; Zimmermann, AC.; Braunstein, S.; Kübler, NR. (Aug 2005). "Adenomatoid odontogenic tumor of the mandible: review of the literature and report of a rare case.". Head Face Med 1: 3. doi:10.1186/1746-160X-1-3. PMID 16270916.

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