|Year : 2015 | Volume
| Issue : 2 | Page : 259-263
Large keratocystic odontogenic tumor of the mandible
Sri Krishna Koppula, Ashutosh Kumar, Devarshi Nandi, Anand Choudhary
Department of Oral Medicine and Radiology, Hazaribag College of Dental Sciences and Hospital, Hazaribag, Jharkhand, India
|Date of Submission||18-Oct-2014|
|Date of Acceptance||20-Oct-2015|
|Date of Web Publication||21-Nov-2015|
Department of Oral Medicine and Radiology, Hazaribag College of Dental Sciences and Hospital, Demotand, Hazaribag - 825 301, Jharkhand
Source of Support: None, Conflict of Interest: None
| Abstract|| |
The odontogenic keratocyst (OKC) is a rare odontogenic cyst of epithelial origin. There are many types of cysts of the jaws, but what make the odontogenic keratocyst unusual are its characteristic features including its potentially aggressive behavior, high recurrence rate, and an association with the nevoid basal cell carcinoma syndrome. Odontogenic keratocysts, now reclassified as keratocystic odontogenic tumors (KCOTs) by the World Health Organization, are a clinical entity with a characteristic microscopic picture, kinetic growth, and biological behavior. The characteristic features are unique among all the different inflammatory and developmental cysts that occur in the jaws. In this report, we present a 35-year-old female patient with a massive KCOT with buccal cortical plate expansion and unusual anteroposterior extension extending from the premolar area up to the condyle.
Keywords: Cyst, keratocystic, odontogenic, tumor
|How to cite this article:|
Koppula SK, Kumar A, Nandi D, Choudhary A. Large keratocystic odontogenic tumor of the mandible. J Indian Acad Oral Med Radiol 2015;27:259-63
|How to cite this URL:|
Koppula SK, Kumar A, Nandi D, Choudhary A. Large keratocystic odontogenic tumor of the mandible. J Indian Acad Oral Med Radiol [serial online] 2015 [cited 2019 Sep 20];27:259-63. Available from: http://www.jiaomr.in/text.asp?2015/27/2/259/170153
| Introduction|| |
The World Health Organization classification of head and neck tumors-2005 describes the keratocystic odontogenic tumor (KCOT) as a benign uni- or multicystic, intraosseous tumor of odontogenic origin, with a characteristic lining of parakeratinized stratified squamous epithelium and potential aggressive, infiltrative behavior. It arises from the proliferation of the epithelial dental lamina in both maxilla and mandible and occurs in patients of all ages. Seventy to eighty percent of KCOTs are found in the mandible, commonly in the angle region. It may be solitary or multiple. The latter is usually one of the stigmata of the inherited nevoid basal cell carcinoma syndrome (NBCCS).  This entity was earlier termed as the odontogenic keratocyst (OKC). KCOTs are fast-growing tumors of the jaw leading to minimal facial deformity and are a risk factor for nearby vital structures such as the maxillary sinus, and the base of the skull in maxilla and the inferior alveolar nerve canal in the mandible. Moreover, there is significant bone destruction, and hollowing and thinning of the bone. Hence, their earliest detection and prompt treatment is compulsory. The KCOTs are long latent, often symptomless, and may attain remarkable dimensions without significant deformation of the jaw bones. An important characteristic of KCOT is its propensity to grow in an anteroposterior direction within the medullary cavity of the bone causing minimal expansion. Compared to other types of jaw cysts, KCOTs have a striking tendency to rapid growth and re-occurrence. In this report, we present a 35-year-old female patient with a massive KCOT with buccal cortical plate expansion and unusual anteroposterior extension extending from the premolar area up to the condyle.
| Case Report|| |
Chief complaint and history
A 35-year-old female patient reported to the Department of Oral Medicine and Radiology with a chief complaint of swelling on the left side of the face with reduced mouth opening since 1 week. On obtaining a detailed history, the patient revealed that the swelling was initially small in size and progressively grew in size in the last 7 months. She further said that the swelling rapidly increased in size in the last 1 month causing facial swelling and asymmetry, which ultimately caused pain in the left side of the face and partial closure of the left eye since 1 week. The patient described the pain as dull throbbing type which was radiating to the left eye and head. There were no other associated symptoms. The patient had visited a local dentist for the same complaint from where she was referred to our department.
On extraoral examination, a single diffuse oval-shaped swelling was noted on the left side of the face, measuring approximately 10 × 10 cm, extending superoinferiorly from the lower eyelid to 1.5 cm below the lower border of the mandible, causing partial obliteration of the eye, and anteroposteriorly from the angle of mouth and ala of nose to the tragus of the left ear involving the ramus and angle of the mandible. The skin overlying the swelling was of the same color as that of the skin on the adjacent areas without any evidence of discharge. However, the skin over the swelling was smooth surfaced in contrast to the skin on the adjacent areas and the contralateral side [Figure 1]a. On palpation of the swelling, a surface rise in temperature and tenderness was noted. The swelling appeared firm in consistency. Compressibility, fluctuation, blanching, and pulsatility were negative. The left submandibular lymph nodes were enlarged, firm, and tender.
On intraoral examination, restricted mouth opening (approximately 1 cm) was evident and the swelling had obliterated the left buccal vestibule with respect to 35, 36, and 37 [Figure 1]b. 35 and 36 were grossly decayed where vestibular tenderness was also present. 37 showed grade I mobility. 38 was clinically missing. No evidence of discharge was noted from either the swelling or the gingival sulcus of the teeth.
Provisional and differential diagnosis
Based on the clinical findings and history, a provisional diagnosis of cellulitis following a dentoalveloar abscess involving 35 and 36 was made, considering the grossly decayed status of 35 and 36. Dentigerous cyst involving 38, ameloblastoma, and KCOT were considered under the differential diagnosis.
Aspiration of the mass after observing all sterile precautions revealed no aspirate.
The complete blood picture was normal except for a hemoglobin percentage of 9.2 g%, total leukocyte count of 18,400 cells/mm 3 , neutrophil percentage of 85%, lymphocyte percentage of 8%, and an erythrocyte sedimentation rate (Wintrobe's method) of 40 mm/h.
The orthopantomograph (OPG) revealed a unilocular radiolucency involving the left posterior body, ramus and angle of the mandible, causing ballooning of the ramus with complete destruction of the anterior border of ramus, coronoid process, and partly the condyle. Distal roots of 37 and 38 were enveloped within the radiolucency. 34, 35, and 36 showed periapical radiolucency. 35 and 36 were grossly carious. A single unilocular spherical radiolucency measuring approximately 1 × 1 cm was evident adjacent to the distal aspect of the crown of impacted 48 [Figure 2]a. In the anteroposterior dimension, the radiolucency extended from the occlusal surface to cementoenamel junction of the horizontally impacted 48. The temporomandibular joint (TMJ) view showed the same findings [Figure 2]b.
Posteroanterior view of skull
The posteroanterior (PA) view of skull showed the same findings seen in OPG. There was evidence of cortical expansion and thinning with loss of cortication involving the entire ramus. The unilocular radiolucency distal to 48 was also evident [Figure 3].
Cone beam computed tomography
The OPG findings were further corroborated by cone beam computed tomography (CBCT). The CBCT images in axial, sagittal, and coronal slices revealed a well-defined hypodense area involving the left mandibular posterior body, angle and ramus, along with the coronoid and condylar processes to a certain extent. The size of the lesion was approximately 44 × 35.4 mm. There was evidence of cortical expansion and thinning with loss of cortication at places throughout the entire mass in the mandible. The internal structure of the lesion appeared completely hypodense and 38 appeared to be submerged in the lesion on the anterior aspect [Figure 4]a and b.
|Figure 4: (a) Panoramic view and (b) Axial section in CBCT scan of the patient|
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Based on the clinical examination and investigations, a working diagnosis of a benign odontogenic tumor in relation to the left side and dentigerous cyst involving 48 was made.
The patient was treated under local anesthesia with infiltration around the periphery of the lesion. Initial incision was given intraorally along the anterior border of the ramus in the left buccal mucosa posterior to the second molar. A window was created to reach the cystic cavity [Figure 5]a. The window was laterally extended followed by extraction of 37 and 38 [Figure 5]b]. Gradually, the contents of the cyst, which were fragile, were evacuated using a surgical curette [Figure 5]c and d] and the lumen was filled with povidone-iodine solution and gauze for 24 h. On the next day, the povidone-iodine gauze was replaced by iodoform gauze, which was repeatedly changed every week [Figure 5]e]. The patient was kept on cefotaxime 1 g injection twice daily, gentamicin 80 mg injection twice daily, and diclofenac sodium tablet SOS for 3 days. Against medical advice, the patient was unwilling for treatment of the radioculency involving 48.
|Figure 5: (a) Intraoperative view. (b) Extracted 37 and 38. (c and d) Cystic contents and (e) Cystic space packed with iodoform gauze|
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The H&E stained sections of the tissue specimen from the left mandible revealed a cystic capsular connective tissue lined by orthokeratinized squamous epithelium. The epithelium of the cyst was uniform and orthokeratinized with a prominent granular layer showing detachment from the underlying connective tissue capsule at a few places. The epithelium also showed palisading basal cell layer with nuclear hyperchromatism of basal cells. The underlying connective tissue capsule was fibrous showing areas of inflammation and extravasated RBCs. The lumen was densely filled with orthokeratin squames [Figure 6]. The histopathologic findings were suggestive of a KCOT.
Over a week following the surgical therapy and with adjunct antibiotics, there was reduction in the facial swelling with a reduction of the swelling in the infraorbital region [Figure 7]a]. There was a significant improvement in facial symmetry and increase in mouth opening in the following 1 month [Figure 7]b]. The functional harmony of the patient also improved with the healing of intraoral surgical wounds. One year after the surgical therapy, there was evidence of significant bone formation without relapse [Figure 7]c.
|Figure 7: Postoperative (a) extraoral view after 1 week, (b) extraoral view after 1 month, and (c) OPG after 1 year|
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| Discussion|| |
In 1876, Mikulicz first described the KCOT as a part of a familial condition affecting the jaws, but the term OKC was first introduced by Philipsen in 1956.  The KCOT, formerly known as OKC, received its new designation in order to better convey its neoplastic nature, its specific histopathologic features, and biological behavior. The KCOT represents between 4 and 12% of all odontogenic cysts and is believed to arise from the dental lamina, with recent studies suggesting the role of the PTCH gene.
Although earlier studies have mentioned a male predilection for KCOT, in the present case, the patient was a female. The mandible is more often involved than the maxilla, and the lesions occur mostly in the molar, angle, and ascending ramus area,  as seen in the present case. The present case showed expansion of the buccal and lingual cortical plates, which is slightly different from the usual behavior of KCOT. An association with impacted teeth is seen in 46.7-75% of cases and the diameter of these cysts commonly ranges from 2 to 7 cm.  The present case was found in association with an impacted 38 with the lesion measuring approximately 4.40 × 3.54 cm.
An important feature of KCOT is its ability to grow in the anteroposterior direction without causing a remarkable swelling that can be diagnosed at an earlier phase.  The KCOT seems to follow the way of least resistance and tends to hollow out the bone, thereby replacing the bone marrow, rather than giving rise to periosteal bone formation, which would result in a bony swelling. Symptoms like pain and paresthesia develop only when the swelling has grown to a larger extent. Most of the KCOTs are discovered incidentally during routine radiographic examination and seldom have any clinical symptoms. Single KCOTs are common, whereas multiple KCOTs are seen in association with NBCCS.  Gorlin and Goltz established the association of multiple basal cell epitheliomas, jaw cysts, and bifid ribs, a combination that is referred as the "Gorlin-Goltz syndrome" or the NBCCS.  In the present case, the radiolucency involving 48 could not be further investigated due to lack of patient consent. Since the radiographic diagnosis of the radiolucency in 48 was more in favor of a dentigerous cyst, and the major and minor criteria were missing, Gorlin-Goltz syndrome was ruled out in this patient.
Imaging studies generally show unilocular radiolucencies with well-demarcated sclerotic margins. Larger lesions may become multiloculated with scalloped borders. The cyst is often times associated with an impacted tooth, and is mistaken to be a dentigerous cyst. Adjacent teeth may be displaced, but root resorption rarely occurs. Computed tomographic (CT) scans and contrast-enhanced magnetic resonance imaging (MRI) may be useful in assessment of cortical perforation and soft tissue involvement. ,,
Histologically, the KCOT has a fibrous wall lined by epithelium with a thin layer of stratified squamous epithelium. This epithelium has a basal layer, which is six to eight cells thick, and a lining of flattened keratotic epithelial cells. The formed keratin lines the luminal surface of the epithelial cells in a slightly wavy or corrugated pattern. The luminal content can have different consistencies described as a "straw-colored fluid," "thick pus-like" material, or a caseous, thick, cheesy, milk white mass. The varying consistencies reflect various densities of the keratinaceous debris. Histologically, KCOTs have been classified into three categories: Parakeratinized, orthokeratinized, or a combination of the two types. Most of them (86.2%) are parakeratinized, 12.2% are orthokeratinized, and 1.6% of them have features of both orthokeratin and parakeratin.
Prognosis and recurrence
Orthokeratinized KCOTs have a substantially lower recurrence rate than the parakeratinized KCOTs. According to Crowley et al.,  parakeratinized OKCs recur in at least 42.6% of cases compared to only 2.2% for orthokeratinized OKCs. The KCOT in the present case was of the orthokeratinized variety. There is also a risk for the malignant transformation of KCOTs with clinical manifestations of spinocellular carcinoma.  KCOTs have a tendency to form satellite cysts, and the epithelial lining locally detaches from the connective tissue wall, which was also noted in the present case. The mitotic activity of the KCOT epithelial cells is greater than any other odontogenic cysts. 
Because of its aggressive nature and high recurrence rate, resection of the jaw is the frequently followed treatment modality. However, it is preferable to perform enucleation in combination with Carnoy's solution or marsupialization, as far as possible, instead of radical resection, to treat KCOT. 
| Conclusion|| |
KCOTs are fast-growing cysts of the jaws. Early diagnosis and prompt treatment is required to prevent facial deformity. Treatment requires utmost care to prevent recurrences because of their high recurrence rates.
Declaration of Patient Consent
The 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 efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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