Signs and Symptoms
- Odontogenic keratocysts are more common in the third to sixth decades of life.
- The male to female ratio is approximately 2:1.
- Most commonly found in the mandible, with half occurring at the angle of the mandible.
- Early odontogenic keratocysts usually do not display symptoms.
- Symptoms may include pain, swelling, and discharge due to secondary infection.

Pathogenesis
- Odontogenic keratocysts originate from the odontogenic epithelium in the alveolus left from tooth development stages.
- They are mainly thought to arise from rests of Serres.

Genetics
- Sporadic and syndromic odontogenic keratocysts are associated with mutations in the PTCH gene on chromosome 9q.
- PTCH is a tumor suppressor gene.
- Loss of PTCH activity leads to a brake in the cell cycle.
- A third of odontogenic keratocysts show mutations in PTCH, resulting in highly proliferative activity.
- This leads to growth of the cyst wall and favors recurrence if the epithelium is incompletely removed.

Nevoid basal-cell carcinoma syndrome
- Multiple odontogenic keratocysts are a feature of nevoid basal cell carcinoma syndrome (NBCCS).
- NBCCS is also known as Gorlin-Goltz Syndrome.
- Almost all individuals with NBCCS have odontogenic keratocysts.
- Diagnosis of multiple odontogenic keratocysts in a child necessitates referral for genetic evaluation.
- Over 80% of NBCCS-related odontogenic keratocysts will have PTCH mutations.

Diagnosis, Treatment, and Follow-up
- Diagnosis of odontogenic keratocysts is usually radiological.
- Definitive diagnosis is through biopsy.
- Aspirational biopsy of odontogenic keratocysts contains a pale, greasy fluid with keratotic squames.
- Protein content of cyst fluid below 4g% is diagnostic of odontogenic keratocysts.
- Smaller and unilocular lesions resembling other types of cysts may require a biopsy to confirm the diagnosis.
- Treatment options include marsupialization, peripheral ostectomy, simple excision, enucleation and cryotherapy, and decompression followed by enucleation.
- Annual radiographic review is recommended for follow-up.
- Long-term clinical follow-up is necessary due to potential recurrences.
- Recurrences can occur many years after treatment.
- Early detection of recurrence allows for minor surgery and curettage.
- Pronto genie keratocysts are known to recur in the posterior mandible.
- Malignant transformation to squamous cell carcinoma is unusual.
- Simple enucleation has a high likelihood of recurrence.
- Recurrence can occur as early as 5 years and as late as 40 years after removal.
- Enucleation success depends on complete removal of the cyst.
- Odontogenic keratocysts may be classified as benign neoplasms due to high recurrence rates.

See also: Cysts of the jaws.

References:
- MacDonald-Jankowski DS (January 2011). Keratocystic odontogenic tumour: systematic review.
- Crispian S (2008). Oral and maxillofacial medicine: the basis of diagnosis and treatment.
- Barnes L, Eveson JW, Reichart P, Sidransky D, eds. (2005). World Health Organization Classification of Tumours: Pathology and Genetics of Head and Neck Tumours.
- Madras J, Lapointe H (March 2008). Keratocystic odontogenic tumour: reclassification of the odontogenic keratocyst from cyst to tumour.
- El-Naggar AK, Chan JK, Grandis JR, Takata T, Slootweg PJ, eds. (2017). WHO Classification of Head and Neck Tumours.

Odontogenic keratocyst (Wikipedia)

An odontogenic keratocyst is a rare and benign but locally aggressive developmental cyst. It most often affects the posterior mandible and most commonly presents in the third decade of life. Odontogenic keratocysts make up around 19% of jaw cysts.

Odontogenic keratocyst
Other names	Keratocystic odontogenic tumour (KCOT)
Micrograph of an odontogenic keratocyst. H&E stain.

In the WHO/IARC classification of head and neck pathology, this clinical entity had been known for years as the odontogenic keratocyst; it was reclassified as keratocystic odontogenic tumour (KCOT) from 2005 to 2017. In 2017 it reverted to the earlier name, as the new WHO/IARC classification reclassified OKC back into the cystic category. Under The WHO/IARC classification, Odontogenic Keratocyst underwent the reclassification as it is no longer considered a neoplasm due to a lack of quality evidence regarding this hypothesis, especially with respect to clonality. Within the Head and Neck pathology community there is still controversy surrounding the reclassification, with some pathologists still considering Odontogenic Keratocyst as a neoplasm in line with the previous classification.