|Year : 2014 | Volume
| Issue : 3 | Page : 349-353
Orthokeratinized odontogenic keratocyst crossing mandibular midline: A diagnostic dilemma
Kapil Kshirsagar1, Sonal Shah1, Supriya Kheur2
1 Department of Oral and Maxillofacial Surgery, Dr. D. Y. Patil Vidyapeeth's Dr. D. Y. Patil Dental College and Hospital, Pimpri, Pune, Maharashtra, India
2 Department of Oral Pathology and Microbiology, Dr. D. Y. Patil Vidyapeeth's Dr. D. Y. Patil Dental College and Hospital, Pimpri, Pune, Maharashtra, India
|Date of Web Publication||18-Mar-2014|
Department of Oral and Maxillofacial Surgery, Dr. D. Y. Patil Vidyapeeth's Dr. D. Y. Patil Dental College and Hospital, Pimpri, Pune - 411018, Maharashtra
Source of Support: None, Conflict of Interest: None
Orthokeratinized odontogenic keratocyst is a less-aggressive non-syndromic variant of odontogenic keratocyst (OKC). In this case report, we are highlighting an unusual presentation of OKC with paresthesia, non-vital teeth, and minimal cortical expansion. The radiograph of the patient revealed a radiolucency crossing the midline in the anterior mandible. This manuscript discusses a case which presented as a diagnostic dilemma due to variable clinical and radiological features mimicking different pathologies occurring in the anterior mandible. We have discussed various clinical and radiographic differential diagnoses of the same.
Keywords: Anterior mandible, bilateral paresthesia, orthokeratinized odontogenic keratocyst
|How to cite this article:|
Kshirsagar K, Shah S, Kheur S. Orthokeratinized odontogenic keratocyst crossing mandibular midline: A diagnostic dilemma. Med J DY Patil Univ 2014;7:349-53
|How to cite this URL:|
Kshirsagar K, Shah S, Kheur S. Orthokeratinized odontogenic keratocyst crossing mandibular midline: A diagnostic dilemma. Med J DY Patil Univ [serial online] 2014 [cited 2020 Apr 2];7:349-53. Available from: http://www.mjdrdypu.org/text.asp?2014/7/3/349/128980
| Introduction|| |
Orthokeratinized odontogenic keratocyst (OOC), a developmental cyst, was first described as a dermoid cyst by Schultz in 1927. In 1945, Philipsen considered this entity as a variant of odontogenic keratocyst (OKC). OOC gained individuality in 1981 as Wright described its clinicopathological features after observing for 30-year period.  Recently, the World Health Organization has designated OOC as a distinct clinicopathologic entity as it has peculiar clinicopathologic aspects when compared to other developmental odontogenic cysts, especially OKCs.  The OOC is histologically characterized by a thin epithelial lining with orthokeratinization and a subjacent prominent granular cell layer. The purpose of this article is to discuss a case which presented as a diagnostic dilemma due to variable clinical and radiological features mimicking different pathologies occurring in the anterior mandible.
| Case Report|| |
A 26-year-old healthy male patient reported to the Department of Oral and Maxillofacial Surgery with the chief complaint of paresthesia over his lower lip and chin since 15 days. Extraoral examination revealed no significant asymmetry of the face [Figure 1]. Intraoral examination showed obliteration of the mandibular buccal vestibule extending from the mandibular right first molar to the left first molar [Figure 2]. On palpation, the swelling was firm in consistency, non-tender, and non-pulsatile. The teeth in the mandibular arch were non-tender and firm, but the vitality test revealed that all the premolars and anterior teeth were non-vital. Orthopantomograph showed the presence of a large unilocular radiolucent lesion extending from the lower left first molar to the lower right second premolar and superoinferiorly from the root apices (involved in the lesion) up to the inferior border with well-corticated smooth margin. However, the lower border continuity was well maintained. The roots of all the teeth involved showed resorption [Figure 3]. Occlusal view showed no expansion of the lingual cortex [Figure 4]. Aspiration of the lesion was negative, suggesting it to be a tumor. Keeping in mind the main complaint of paresthesia, coupled with negative aspirate and rapid growth of the lesion in marrow spaces, a diagnosis of malignancy was suspected. Thus, a positron emission tomography (PET) scan of the patient was done to rule out malignancy or any other systemic pathology. The PET scan was clear.
On the basis of the clinical and radiological features and considering the probable benign nature of the present case, complete excision of the lesion was planned. Endodontic treatment was done for the premolars and anterior teeth.
|Figure 3: Preoperative orthopantomogram (OPG) showing well defined radiolucency in the anterior mandible, extending from the right mandibular first molar to the left second premolar|
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|Figure 4: Occlusal radiograph showing no lingual cortical bone expansion|
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The case was taken up under general anesthesia. Mucoperiosteal flap was raised to expose the underlying bone. Thinned buccal cortex was removed to expose the underlying lesion [Figure 5]. The lesion seemed to be well encapsulated and soft on palpation. A slit was made on the capsule to reveal yellowish-white, thick cheesy material [Figure 6]. After evacuating the cheesy material, cystic lining was seen which was easily separated from the bone and removed in toto [Figure 7]. Apicectomy was done on all obturated teeth and the lower left first molar was extracted. A small quantity of gelfoam was used to achieve hemostasis.
|Figure 6: Thick yellowish-white cheesy content retrieved from the lesion|
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Microscopically, it showed the presence of a central cystic lumen lined by 6-8 cell layered corrugated orthokeratinized stratified squamous odontogenic epithelium showing no rete pegs and a connective tissue capsule [Figure 8]. There was no evidence of any inflammatory cell infiltration. These features were consistent with diagnosis of OOC.
|Figure 8: Hematoxylin and eosin stained section showing corrugated orthokeratinized odontogenic epithelial lining representative of OOC (original magnifi cation 100×)|
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Malignant tumors may be found as a single periapical radiolucency mimicking a more benign lesion. They usually erode too much of alveolar crestal bone before they arrive at the apex. Radiologically, they show ragged borders and well or poorly defined periapical radiolucency. Large, ragged, well-defined tumor that has destroyed a large segment of the surface bone and has involved the apex of the tooth is also seen. Root resorption may be a feature.
Clinically, paresthesia of the soft tissues is usually seen, but the patient may be otherwise asymptomatic. Expansion of the jaws is a feature of advanced lesion. The overlying mucosa is normal in the initial stages. Later, it becomes ulcerated. It mimic benign conditions initially, and unless the other subtle telltale signs and symptoms are recognized, the clinician will not be alerted to the seriousness of the case.  Amongst the various malignancies presenting with similar clinical features is osteosarcoma.
Osteosarcoma is one of the common malignancies affecting the mandible. Mean age of the neoplasm is in the third decade.  The patient generally presents with swelling and paresthesia. Radiographically, sun-burst appearance is very common. Presence of destructive, unicentric lesion with poorly defined margins and a predominantly sclerotic, lytic, or mixed radiographic pattern should lead one to suspect an osteogenic sarcoma. , It generally involves a more radical surgery followed by adjunct chemotherapy.
Primary intraosseous carcinoma (PIOC) occurs mainly in adults in the sixth to seventh decade of life and the incidence has a male to female ratio of 3:1. It occurs usually in the posterior mandible. Its etiology is not clear; however, the most common factor may be a reactive inflammatory stimulus with or without a predisposing genetic cofactor.  PIOC can appear radiographically like any other cysts and tumors, thus it is important to be considered in the differential diagnosis of radiolucent lesions of the jaws. ,, In a pooled analysis of 33 cases recorded in world literature, performed by Thomas et al., pain was the commonest presenting feature in 17 (54.8%) patients, followed by swelling of the jaw in 16 (51.6%) and sensory disturbances in 5 (16.1%). In many instances, the nonspecific clinical findings may mimic inflammatory dental processes.  There exists a keratinizing variant which can be further confused with other keratinizing cysts and tumors. 
Metastatic carcinoma was excluded from our differential diagnosis as there was no evidence of carcinoma elsewhere in the patient. As the aspiration of the pathology was negative in our case, a solid benign tumor was the most probable differential diagnosis.
Ameloblastoma presents as a painless, slow-growing lesion causing migration and loosening of teeth, along with expansion of the cortical plates and paresthesia of the lip. The age range is 20-50 years and is five times more common in mandible than in maxilla, but more common in the posterior region. In cystic type of lesion, the aspirate could be negative or straw-colored fluid may be present. This can be confused with radicular cyst. Radiographically, unicystic variant may present as a lytic radiolucency along with root resorption.  The treatment of ameloblastoma ranges from enucleation to radical resection, depending upon the extent and histopathologic variant of the lesion.
Central giant cell granuloma more commonly affects females above 30 years of age. Mandible is more affected than maxilla. Anterior jaws are more commonly affected, and often, the lesion crosses the midline. Paresthesia is absent. The lesion is painless, slow growing, and shows expansion and thinning of cortical plates. Initial stage shows cyst-like radiolucency. The lesion seldom perforates into soft tissues. Covering mucosa appears normal unless traumatized. Expanding lesion may cause migration of teeth, but root resorption is not the rule. Serum levels can be diagnostic, but secondary systemic involvement has to be ruled out.  The treatment involves aggressive curettage with peripheral ostectomy.
Central hemangioma of the bone rarely occurs in the jaws. It may be observed as a cyst-like radiolucency with an empty cavity and a hyperostotic border. Resorption of roots of the involved teeth is sometimes seen. Usual complaint is slow-growing asymmetry of the jaw, localized gingival bleeding, numbness, and tenderness. Females are more affected than males, and the mandible (anterior region) is more affected than the maxilla. Some tumors demonstrate pulsation and bruits. Expansion of cortices with bony hard swelling is seen with normal-appearing mucosa. Teeth may exhibit a pumping action. Aspiration shows blood.  Treatment involves intralesional injections of sclerosing agents and embolization of feeder vessels.
As the case presented with a unicystic radiolucency with scalloped borders, cystic pathologies need to be evaluated as differential diagnosis.
Radicular cyst is the most common inflammatory odontogenic cyst associated with non-vital teeth. Expansion of the cortical plates is seen with normal mucosa. Initially it is bony hard, but later produces crackling sound as the bone resorbs. Root resorption may also be a feature. Aspiration shows straw-colored fluid with cholesterol crystals.  It generally requires endodontic therapy of the involved teeth with curettage and apicectomy.
Traumatic cysts are more commonly seen in the mandible than in the maxilla. The age is usually above 25 years, with history of trauma. Teeth involved are vital with intact lamina dura. Root resorption is absent. Aspiration is negative, although sometimes serosanguinous fluid or even blood may be present. The fact that the pulps of the associated teeth are vital in traumatic bone cyst clearly distinguishes it from a radicular cyst.  The treatment of choice involves surgical curettage.
| Discussion|| |
Histopathologically, the lesion was diagnosed as OOC, which is considered as a less-aggressive variant of the keratinizing cystic odontogenic tumor. The OOC was recognized as a variant of OKC based on the abundance of orthokeratin in the cystic lining.  The prevalence of OOC is very low and it is difficult to diagnose due to non-specific clinical and radiological findings. OKC is an aggressive cystic lesion with a tendency to recur around 3-60%, whereas OOC has a recurrence rate of 2.2%. 
In the present case, the entire presentation of the lesion was misleading with paresthesia of lower lip, non-vital lower anterior teeth, and minimal buccal and lingual cortical expansion, with young age of the patient. Thus, our case showed overlap of all the differential diagnosis entities, thereby increasing the risk of error in the treatment as segmental mandibulectomy.
Although there is considerable predilection for its occurrence in the mandibular third molar region and ramus, it may also occur in the maxilla. Anterior mandible is an uncommon site, with the lesion crossing the midline being a unique occurrence. 
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