|Year : 2016 | Volume
| Issue : 3 | Page : 403-407
Keratocystic odontogenic tumor of mandible
Ankita Bohra, Vipul Udawat, Anitha Bhemappa, Sugandha Arya
Department of Oral Medicine and Radiology, Vyas Dental College and Hospital, Jodhpur, Rajasthan, India
|Date of Web Publication||17-May-2016|
Vyas Dental College and Hospital, Jodhpur - 341 008, Rajasthan
Source of Support: None, Conflict of Interest: None
Keratocystic odontogenic tumor is considered to be a benign cystic neoplasia of jaw bone with a higher rate of recurrence. It is noted to be third most common odontogenic cyst after radicular and dentigerous cyst. Most common location is posterior mandible and ascending ramus. A case with odontogenic keratocyst of the right posterior mandible is presented with proper clinical and radiographic examinations along with histopathological investigation. Cystic lesion was surgically resected with iliac crest bone graft replacement and reconstruction plate placement. Follow-up of 1 year is completed with repeated radiographic examinations in 4 months interval with no evidence of recurrence.
Keywords: Cystic neoplasm, keratocystic odontogenic tumor, odontogenic cyst, odontogenic keratocyst
|How to cite this article:|
Bohra A, Udawat V, Bhemappa A, Arya S. Keratocystic odontogenic tumor of mandible. Med J DY Patil Univ 2016;9:403-7
| Introduction|| |
Keratocystic odontogenic tumor (KCOT) is a benign cystic neoplasia of jaw bone. It has unique histopathological and clinical behavior because of its higher rate of recurrence and capacity of epithelial turnover as compared to other odontogenic cysts. It was first described by Philipsen in 1956 as (OKC).  Due to its neoplastic potential, OKC are considered to be benign cystic neoplasms rather than cysts. It has been designated as "KCOT" by World Health Organization (WHO) classification of head and neck tumors in the year 2005.  Presenting here a case report of KCOT of the mandible with a review of literature.
| Case Report|| |
A 45-year-old male was referred to Department of Oral medicine and Radiology with a complaint of pain and swelling in lower right back jaw since 2-3 years [Figure 1] and [Figure 2]. Pain was continuous and dull in nature. There was no previous history of any trauma or any other surgical procedure. Medical history was unremarkable. The patient gave no history of hazardous habit. On local examination, slight facial asymmetry was present because of a diffuse swelling was presented over the right mandibular angle, approximately 6 cm × 5 cm in its anteroposterior dimension and 4 cm × 3 cm superioinferiorly. Swelling was nontender and firm in consistency. Skin over the swelling was normal. The right mandibular lymph node was palpable, mobile, and slightly tender. On intraoral examination, mouth opening was normal, mild vestibular tenderness was present with respect to the posterior right buccal vestibule [Figure 3] and [Figure 4]. Radiographic examination was suggested (intraoral peri-apical radiograph [IOPA], mandibular occlusal, orthopantamogram, computed tomography [CT] scan). IOPA of the right posterior mandible with respect to 46, 47 revealed a well-defined radiolucency present distal to the distal root of 47, with slightly scalloped borders [Figure 5]. Occlusal radiograph revealed no bucco-lingual expansion of cortical plates in favor of OKC [Figure 6]. On panoramic radiograph an apparently multilocular unilateral radiolucency was present on right mandible involving mandibular angle ramus on the right side 6 cm × 4 cm in greatest in anteroposterior dimension and 3 cm × 3 cm superioinferiorly with incomplete septa present within internal radiolucent lumen giving multilocular appearance [Figure 7]. CT scan was performed to measure the accurate extend of the lesion within the bone. CT examination of mandible, a multilocular unilateral expansile lesion was seen in right posterior mandibular angle and ascending right ramus of the mandible. About 29 mm anteroposterior, 20 mm transversely and 29 mm in vertical dimensions size of Lesion caused a breach of the mandibular cortex [Figure 8] and [Figure 9]. Radiographic diagnosis KCOT of the right mandible was given. Aspiration of the cystic lumen was taken which consisted of cheesy material with a clear fluid. Incisional biopsy was done. Histopathologic examination showed cyst wall consisted of 7-8 cells thick keratinized stratified squamous epithelium and noninflammatory fibrous connective tissue wall along with small satellite islands of odontogenic epithelium and keratinaceous debris [Figure 10]. Based on clinical and histo-pathological investigations, a final diagnosis of a KCOT. Surgical segmental resection of the right mandible was performed with removal of complete cystic lining with surrounding soft tissue with the use of Carnoy's solution, to minimize the chances of recurrences followed by iliac crest graft placement held in place by reconstruction plate placement. Post-operatively patient managed with intravenous antibiotics, analgesics and other supportive measures. The patient is under adequate follow-up from past 1 year with repeated panoramic radiographs taken after 3 months duration and showed no signs of recurrence of the lesion [Figure 11].
|Figure 5: Intraoral periapical radiograph showing diffuse radiolucency distal to 47|
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|Figure 7: Orthopantamogram showing a unilateral diffuse multilocular radiolucency in right mandibular ramus|
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|Figure 11: Hemi resection of mandible followed by titanium reconstruction plate|
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| Discussion|| |
KCOT is defined as "a benign uni- or multi-cystic, intraosseous tumor of odontogenic origin, with a characteristic lining of parakeratinized stratified squamous epithelium and potential for aggressive, infiltrative behavior." It arises from the dental lamina or basal cells of the oral epithelium.
WHO in 2005 included OKC under a neoplasm. Most commonly occur in third and fifth decade. There is slight male predilection.  Mandibular occurrences are more as compared to the maxilla, with a marked tendency to involve posterior body and ascending mandibular ramus.  OKC tends to grow in anteroposterior direction within the medullary cavity without causing much of buccolingual bone expansion. Radiographically, a well-defined radiolucency with smooth corticated sometimes scalloped margins with internal septae within the medullary cavity gives it a multilocular appearance. , The lumen may be cloudy because of keratin, and the CT number of luminal contents may be higher than the other cystic fluids. Sometimes, focal areas of perforation of cortical plates may be seen in plain radiographs and CT. Approximately, 20-45% of cases documented associated with unerupted tooth and can provide a diagnosis of a dentigerous cyst. , OKC shows less instances of root resorption as compared to the dentigerous cyst. The histological finding shows thin uniform fibrous wall with non-inflammatory changes and small satellite cysts/island of odontogenic epithelium. , The thickness of cystic stratified epithelium changes to 6-8 cells thick with a detachment of fibrous wall. The lumen shows parakeratotic epithelial cells giving a wavy corrugated appearance. ,,, Basal cell layer composed of palisaded arrangement of the cuboidal/columnar hyper chromatic epithelial cells. ,, High recurrence rate can be attributed to the satellite cysts that are retained during enucleation, thin, and fragile cystic wall that can be left behind. Carnoy's solution acts as a fixative agent and its use in odontogenic cysts and tumors shows a reduction in recurrence rate to 9%.
The differential diagnosis for KCOT includes ameloblastoma, central giant cell granuloma, odontogenic myxoma, calcifying epithelial odontogenic cyst, and dentigerous cyst. The tendency for multiplicity associated with a gene level disturbance of chromosome 9 as in nevoid basal cell carcinoma syndrome, also referred to as Gorlin-Goltz syndrome. It is s transmitted as an autosomal dominant trait.
Multiple OKCs are associated along with other manifestations such as including multiple basal cell carcinomas, benign dermal cysts, palmar-plantar pits; cranio-dentofacial anomalies, such as OKC, malocclusion, broad nasal bridge, and increased head circumference; skeletal anomalies, including frontal and parietal bossing and mandibular prognathism, as well as costal anomalies involving the rib and vertebrae; ophthalmologic abnormalities, including hypertelorism, congenital blindness, and strabismus; and neurologic anomalies, including calcifications of the falx cerebri, bony bridging of the sella turcica, and medulloblastoma.
OKC is to an important odontogenic tumor with neoplastic characteristics. Proper clinical and radiographic examination along with histopathological investigations should be performed. Due to its recurring nature, adequate follow-up is a must at least for 3-5 years of duration including clinical and radiographical check-ups.
Declaration of patient consent
Th e authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due eff orts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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