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.