Odontogenic Keratocyst 

 

Odontogenic keratocyst (OKC) is a parakeratin lined cyst like lesion within bone.

OKCs mostly occur in the 2nd and 3rd decades of life; although can occur over a wide age range with male predilection. Odontogenic keratocyst comprises of 4 to 12 percent of all odontogenic cysts. Ninety percent of odontogenic keratocysts are solitary. Multiple cysts are found in Nevoid Basal Cell Carcinoma Syndrome / Gorlin Syndrome[1]. 

The most commonly involved body part in mandible, 65-85%; mostly posterior mandible. Normally, they are associated with third molars but may be present without associating with third molars; rarely occur in soft tissues.

They are considered to arise from dental lamina. 

Clinical Features 

Odontogenic keratocysts are often asymptomatic. They are incidentally discovered on radiographs. They can cause symptomatic swelling. They can cause parasthesia of lip and teeth. Symptoms of pain and drainage are found if secondarily infected. They can cause local bone and soft tissue destruction, but usually spare teeth and roots.

Swelling observed at the right buccal mucosa (dotted area) posterior to the orifice of Stensen’s duct-arrow head [3].

Odontogenic keratocyst-exposed anterior to the masseter muscle.

Radiographic features 

Mostly, they are seen as small unilocular radiolucent lesions with variable sclerotic margins. Larger lesions are often seen multilocular with variable scalloped margins. Therefore, They may resemble radicular cyst, dentigerous cyst, lateral periodontal cyst, and ameloblastoma.

Keratocystic Odontogenic tumer in orthopantomograph being shown as  multiple radiolucencies associated with mandibular anterior region, maxillary right and left as well as mandibular left impacted third molar tooth [5].

Classic look to a keratocyctic odontogenic tumor in the right mandible in the place of a former wisdom tooth. Unicystic lesion growing along the bone. Lesion was seen by oral surgeon on routine panoramic radiography without any symptoms [2].

Histology

Histological findings in the above slides are
a: The cyst wall is lined with parakeratinized squamous cells with a corrugated surface.
b: Nuclei of the cells in the basal layer are palisaded. The rete ridge of the epithelium is not evident [3]. 

Differential Diagnosis

1. Ameloblastoma
2. Dentigerous cyst
3. Peri-apical cyst
4. Lateral periodontal cyst

Prognosis

Recurrence rates of OKC are from 20% to 56% with enucleation alone. Resection have been reported to have no recurrences, but it may be considered excessive for a benign cyst.

Multiple lesions can occur when OKCs are associated with Nevoid Basal Cell Carcinoma Syndrome (NBCCS)/Gorlin Syndrome Therefore, early diagnosis and follow-up of the patient with OKC is important as there is always a possibility of developing other features of NBCCS in the future.

Treatment

Treatment is given taking into consideration of recurrence and morbidity. Following are the treatments given alone or in combination to a patient of odontogenic Keratocyst. 

1. Decompression.
2. Enucleation with possible curettage.
3. Chemical curettage with Carnoy’s solution.
4. Marsupialization.
5. Resection.

Case Studies

For further studies on case reports, you can consult the reference number 4 and 5.

Ref:

1. Morrison A. Odontogenic keratocyst. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/mandiblemaxillakeratocyst.html. Accessed September 11th, 2022.
2. https://en.wikipedia.org/wiki/File:Classic_keratocystic_odontogenic_tumour.jpg
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3837368/figure/F1/
4. https://www.pathologyoutlines.com/caseofweek/case503.htm
5. K. M. Veena, Rekha Rao, H. Jagadishchandra, Prasanna Kumar Rao, "Odontogenic Keratocyst Looks Can Be Deceptive, Causing Endodontic Misdiagnosis", Case Reports in Pathology, vol. 2011, Article ID 159501, 3 pages, 2011. https://doi.org/10.1155/2011/159501