Odontogenic keratocyst

Odontogenic keratocyst
	External resources
EHVSC	10179 10178
Wikipedia	keratocystic odontogenic tumour
Pathology Outlines	topic/mandiblemaxillakeratocyst
Rosai Collection	14023

Odontogenic keratocyst
	Diagnosis in short
	; Keratocystic odontogenic tumour. H&E stain.
Synonyms	odontogenic keratocyst (old term)
LM	stratified epithelium with "ribbon-like appearance" with palisaded basal cell layer, parakeratosis, artefactual separation of epithelium from the basement membrane
LM DDx	odontogenic cyst (dentigerous cyst), squamous cell carcinoma
Site	usually mandible - see odontogenic tumours and cysts
Syndromes	nevoid basal cell carcinoma syndrome
Signs	mass lesion
Prevalence	uncommon
Clin. DDx	ameloblastoma

Odontogenic keratocyst, abbreviated OKC, is an uncommon odontogenic cyst.

It was known as keratocystic odontogenic tumour, abbreviated KOT, from 2005 to 2017.^[1]^[2]

General

May be associated with nevoid basal cell carcinoma syndrome.
Very rarely transforms to a squamous cell carcinoma.^[3]^[4]

Clinical

Features:^[5]

Most common presentation: swelling.

Gross

Location: usually mandible.
May mimic ameloblastoma radiologically.

Microscopic

Features: ^[6]

Stratified epithelium (resembling squamous epithelium) with:
- "Ribbon-like appearance" - important.
  - Typically 8-10 cell layers thick - with relatively uniform thickness.
  - Lacks rete ridges.
- Palisaded basal cell layer.
Parakeratosis (keratinized cells with nuclei) - key feature.
Artefactual separation of epithelium from the basement membrane.

DDx:

Odontogenic cyst.
- Orthokeratinized odontogenic cyst^[7] - usu. dentigerous cyst - has orthokeratosis instead of parakeratosis.
  - Orthokeratosis = keratinized cells no nuclei; parakeratosis = keratinized cell with nuclei.

Images

KOT - intermed. mag. (WC)
KOT - very high mag. (WC)
KOT - poor quality. (WC)
KOT - showing artefactual clefting - poor quality. (WC)

www:

KOT (els-cdn.com).^[8]

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Right Maxillary Sinus Mass, Excision:
     - Consistent with odontogenic keratocyst (benign ribbon-like squamous epithelium
       with keratinization, separated from the underlying hyaline stroma with cartilage).
     - Benign respiratory mucosa with mild inflammation.
     - NEGATIVE for malignancy.

References

↑ 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.
↑ El-Naggar, Adel K, ed. (2017), WHO Classification of Head and Neck Tumours, WHO/IARC Classification of Tumours, 9 (4th ed.), Lyon, France: IARC Press, ISBN 978-92-832-2438-9, http://publications.iarc.fr/Book-And-Report-Series/Who-Iarc-Classification-Of-Tumours/Who-Classification-Of-Head-And-Neck-Tumours-2017.
↑ Lee, JW.; Gates, R.; Wignall, A. (Aug 2011). "Squamous cell carcinoma arising from a keratocystic odontogenic tumor.". Otolaryngol Head Neck Surg 145 (2): 356-7. doi:10.1177/0194599811399270. PMID 21493332.
↑ Tan, B.; Yan, TS.; Shermin, L.; Teck, KC.; Yoke, PC.; Goh, C.; Balakrishnan, A.. "Malignant transformation of keratocystic odontogenic tumor: Two case reports.". Am J Otolaryngol 34 (4): 357-61. doi:10.1016/j.amjoto.2013.01.002. PMID 23374486.
↑ 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.
↑ Thompson LDR. Head and neck pathology - (Foundations in diagnostic pathology). Goldblum JR, Ed.. Churchill Livingstone. 2006. ISBN 0-443-06960-3.
↑ Macdonald-Jankowski, DS. (Dec 2010). "Orthokeratinized odontogenic cyst: a systematic review.". Dentomaxillofac Radiol 39 (8): 455-67. doi:10.1259/dmfr/19728573.
↑ URL: http://www.sciencedirect.com/science/article/pii/S0968605305000992#fig5. Accessed on: 11 March 2013.

[pmid18353202-1] 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.

[isbn_978-92-832-2438-9-2] El-Naggar, Adel K, ed. (2017), WHO Classification of Head and Neck Tumours, WHO/IARC Classification of Tumours, 9 (4th ed.), Lyon, France: IARC Press, ISBN 978-92-832-2438-9, http://publications.iarc.fr/Book-And-Report-Series/Who-Iarc-Classification-Of-Tumours/Who-Classification-Of-Head-And-Neck-Tumours-2017.

[pmid21493332-3] Lee, JW.; Gates, R.; Wignall, A. (Aug 2011). "Squamous cell carcinoma arising from a keratocystic odontogenic tumor.". Otolaryngol Head Neck Surg 145 (2): 356-7. doi:10.1177/0194599811399270. PMID 21493332.

[pmid23374486-4] Tan, B.; Yan, TS.; Shermin, L.; Teck, KC.; Yoke, PC.; Goh, C.; Balakrishnan, A.. "Malignant transformation of keratocystic odontogenic tumor: Two case reports.". Am J Otolaryngol 34 (4): 357-61. doi:10.1016/j.amjoto.2013.01.002. PMID 23374486.

[pmid17928730-5] 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.

[6] Thompson LDR. Head and neck pathology - (Foundations in diagnostic pathology). Goldblum JR, Ed.. Churchill Livingstone. 2006. ISBN 0-443-06960-3.

[pmid21062939-7] Macdonald-Jankowski, DS. (Dec 2010). "Orthokeratinized odontogenic cyst: a systematic review.". Dentomaxillofac Radiol 39 (8): 455-67. doi:10.1259/dmfr/19728573.

[8] URL: http://www.sciencedirect.com/science/article/pii/S0968605305000992#fig5. Accessed on: 11 March 2013.

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Odontogenic keratocyst

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