Ameloblastoma

From Libre Pathology
Jump to: navigation, search
Ameloblastoma
Diagnosis in short

Ameloblastoma. H&E stain.

LM stellate reticulum (star-shaped cells), tall columnar cells that have palisaded nuclei with reverse polarization, subnuclear vacuolization, +/-giant cells, +/-subepithelial hyalinization (eosinophilic acellular amorphous material)
Subtypes solid/multicystic, unicystic
LM DDx adenomatoid odontogenic tumour, ameloblastic fibroma
Site usu. mandible - see odontogenic tumours and cysts

Prevalence uncommon
Prognosis locally aggresive, rarely malignant
Clin. DDx keratocystic odontogenic tumour, odontogenic cysts

Ameloblastoma is an odontogenic tumour.

General

  • Osteous lesion.
  • Usually mandible.[1]
    • In a review of 3677 cases, the mandible-to-maxilla ratio was 5 to 1.[2]
  • May arise from an odontogenic cyst,[3] e.g. dentigerous cyst.[4]
  • Can be malignant[5] - rare.[6]

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.

Gross

  • Mass - usu. mandible or maxilla.[6]
    • Mandile most common.

Microscopic

Features:[7]

  • Stellate reticulum - star-shaped cells, found in a developing tooth.
  • 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 perpendicular to the basement membrane -- key feature.
    • Subnuclear vacuolization.
  • +/-Giant cells.
  • +/-Subepithelial hyalinization (eosinophilic acellular amorphous material).
    • Seen deep to the basement membrane.
  • Variable morphology (see below - morphology).

DDx (nuclear palisading):

Images

www:

Morphology

  • Not prognostic.

Morphologic variants:

  • Follicular ameloblastoma (classic appearance).
  • Plexiform ameloblastoma (does not have prominent palisading).
  • Acanthomatous ameloblastoma.
  • Desmoplastic ameloblastoma.
  • Basaloid ameloblastoma.

See also

References

  1. URL: http://www.waent.org/archives/2010/Vol3-2/20100618-ameloblastoma/jaw-tumor.htm. Accessed on: 30 November 2011.
  2. Reichart, PA.; Philipsen, HP.; Sonner, S. (Mar 1995). "Ameloblastoma: biological profile of 3677 cases.". Eur J Cancer B Oral Oncol 31B (2): 86-99. PMID 7633291.
  3. Eversole, LR. (Nov 1999). "Malignant epithelial odontogenic tumors.". Semin Diagn Pathol 16 (4): 317-24. PMID 10587275.
  4. 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/.
  5. Goldenberg, D.; Sciubba, J.; Koch, W.; Tufano, RP. (Oct 2004). "Malignant odontogenic tumors: a 22-year experience.". Laryngoscope 114 (10): 1770-4. doi:10.1097/00005537-200410000-00018. PMID 15454770.
  6. 6.0 6.1 Chou, YH.; Jhuang, JY.; Chang, MH.; Huang, WC.; Hsieh, MS. (Jun 2013). "Metastasizing Ameloblastoma With Localized Interstitial Spread in the Lung: Report of Two Cases.". Int J Surg Pathol. doi:10.1177/1066896913491321. PMID 23775022.
  7. URL: http://www.pathconsultddx.com/pathCon/diagnosis?pii=S1559-8675%2806%2970616-7. Accessed on: March 9, 2010.