Indian Journal of Dental Research

: 2011  |  Volume : 22  |  Issue : 1  |  Page : 157--160

Keratocystic odontogenic tumor with impacted maxillary third molar involving the right maxillary antrum:An unusual case report

Abhishek Gupta, Bhagavandas Rai, Manju A Nair, Mitul K Bhut 
 Department of Oral and Maxillofacial Surgery, Pacific Dental College, Debari, Udaipur - 313 024, Rajasthan, India

Correspondence Address:
Abhishek Gupta
Department of Oral and Maxillofacial Surgery, Pacific Dental College, Debari, Udaipur - 313 024, Rajasthan


The odontogenic keratocyst (OKC), first described by Phillipsen in 1956, has metamorphosized as a keratocystic odontogenic tumor (KCOT) as reported in WHO classification of head and neck tumors in 2005. KCOT is a benign intraosseous neoplasm of the jaw and its occurrence in maxilla is unusual and its appearance in maxillary antrum along with maxillary impacted third molar is very uncommon. This article reports a case of KCOT associated with impacted maxillary third molar in right maxillary antrum and describes its rare site of occurrence.

How to cite this article:
Gupta A, Rai B, Nair MA, Bhut MK. Keratocystic odontogenic tumor with impacted maxillary third molar involving the right maxillary antrum:An unusual case report.Indian J Dent Res 2011;22:157-160

How to cite this URL:
Gupta A, Rai B, Nair MA, Bhut MK. Keratocystic odontogenic tumor with impacted maxillary third molar involving the right maxillary antrum:An unusual case report. Indian J Dent Res [serial online] 2011 [cited 2020 Oct 22 ];22:157-160
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Full Text

The term odontogenic keratocyst (OKC) was first described by Phillipsen in 1956. [1] OKC is now designated by the WHO as keratocystic odontogenic tumor (KCOT) in 2005 and is defined as 'a benign unicystic or multicystic, intraosseous tumor of odontogenic origin, with a characteristic lining of parakeratinized stratified squamous epithelium and potential for aggressive, infiltrative behavior. [2],[3] These cysts are generally derived from epithelial remnants of the tooth germ and another origin is from basal cells of the overlying oral epithelium.

KCOT is seen in the second and third decade of life [1] with a peak incidence between 11 and 40 years of age and rare occurrence in individuals older than age of 70 years. KCOT has a slight male predilection. [1] Its common site is in mandible than maxilla; in mandible, the majority of the cysts occur in mandibular ramus and molar area. [1] Unusual location has also been reported, such as the anterior portion of maxilla, maxillary antrum, and maxillary third molar area. But in maxilla, canine region is the most common location for KCOT [4] and occurrence of KCOT in maxillary antrum involving the impacted maxillary molar is very rare. [1],[5],[6] Six cases have been reported with KCOT in maxillary antrum. In addition, the OKC is the specific type of odontogenic cyst that may be associated with the nevoid basal cell carcinoma syndrome [1],[3] (NBCCS).

Radiographically KCOT appears as well defined radiolucency which may be unilocular or multilocular. KCOT are poor bone resorbers and hence involve the cancellous bone in early stages of its development. The compact bone is invaded much later; therefore very little expansion is observed in keratocyst. [7] Cystic lesion which has been reported for long periods of time showed scalloped margins due to the regional resorption of the surrounding bone. [7] Treatment approaches vary in different studies from:- marsupilization, enucleation and primary closure, enucleation and packing open with adjuvant therapy as carnoy's solution or cryotherapy, to marginal or radical section. [8]

KCOT has a high recurrence rate. [9] The recurrence of KCOT in patient with basal cell nevus syndrome occurred more; a high rate of recurrence in multilocular radiographic appearance was also found, [9] and histological presence of one or more daughter cysts was significantly related to recurrence. KCOT totally enucleated in one piece exhibited a lower recurrence frequency than those removed in several pieces.

 Case Report

A 64-year-old female patient was referred to the Department of Oral and Maxillo Facial Surgery, Pacific Dental College and Hospital, India, with chief complaint of pain in right cheek region since 2 months. The patient gave the history of mild intermittent nonradiating pain in the right cheek region. Extraoral examination revealed no swelling over the right cheek region but tenderness was present and no discharge from the nose. Intra-oral examination revealed missing teeth of 18, 13, 23, 28, 37, 33, 46. Orthopantomograph showed the presence of impacted 18, 13, 28 and impacted maxillary right third molar was displaced in right maxillary antrum [Figure 1]. To visualize- the lesion in more detail, computed tomography (CT) was performed in coronal and axial planes. CT revealed that- an expansile, low density cystic lesion was seen in right maxillary antrum with impacted third molar tooth in anterior causing thinning of the antral wall, widening of ipsilateral maxillary osteum and blockage of osteomeatal unit, bony nasal septum was minimally deviated toward left [Figure 2]. A tentative diagnosis of dentigerous cyst was made.{Figure 1}{Figure 2}

The surgical enucleation of the lesion was planned under general anesthesia. An aspiration biopsy was performed. It exposed cheesy white content [Figure 3]. Right maxillary antrum was accessed using the Caldwell Luc technique, antral wall eroded by the cystic lesion, after osseous trepanation cystic lesion was visualized [Figure 4] The lesion containing impacted maxillary third molar enucleated in single piece and wall of bony cavity were curetted, and prophylactic chemical cauterization was done using Carnoy's Solution [Figure 5]. A medicated gauze pack was kept inside bony cavity with one end out through right nostril. This pack was removed after 2 days.{Figure 3}{Figure 4}{Figure 5}

Enucleated tissue was sent for histopathological examination. Histopathological report showed parakeratinized stratified squamous epithelial lining with 6-8 cell layer thickness showing surface corrugation, connective tissue stroma was loose, fibro cellular in nature with trabecular bone and showed the presence of chronic inflammatory cells like lymphocytes, lipid laden macrophages and plasma cells [Figure 6]. A pseudo stratified ciliated columnar epithelium representing maxillary antrum lining. These finding were suggestive of infected keratinized cystic odontogenic tumor (KCOT). The healing was satisfactory and the patient was followed up for 1 year with no evidence of recurrence.{Figure 6}


Jaw cysts are very common due to the presence of odontogenic epithelial remnants. Among the jaw cysts OKC is the third most common. [4] The WHO recommends the term KCOT because of its aggressive and infiltrative nature. [2],[3] Presence of daughter cysts, thin friable cystic lining and various other explanations are given for the high recurrence of KCOT. [6]

KCOT is commonly occurs in the second and third decade of life and slightly predilection for men. In our case, the female patient was in her sixth decade of life. Most common site for KCOT is the mandibular ramus and molar area. [1] In maxilla, common site for the occurrence of KCOT is the canine region. [4] Less than 1% of all cases of KCOT occur in maxilla with maxillary antrum involvement. [1] We report a rare site of the occurrence of KCOT associated with impacted maxillary third molar in right maxillary antrum. It is difficult to diagnose clinically due to the lack of consistent clinical characteristics. In this case, the patient had only intermittent pain in right cheek region. Radiographically KCOT appears as a well - defined unilocular or multilocular radiolucency. [7] Orthopantomograph shows impacted maxillary third molar in right maxillary antrum, its radiographic appearance may be misinterpreted so CT was required for information on extent of lesion, helping to diagnose, and perioperative management.

Other cystic and neoplastic diseases such as dentigerous cyst, lateral periodontal cyst, radicular cyst, ameloblastoma, adenomatoid odontogenic tumor can present with same radiological features. [1] Therefore if clinical and radiological features indicate KCOT, a definitive diagnosis cannot be made without histopathological examination. Ideally histopathological examination, accurate clinical, ragiographic, intraoperative observation along with most effective treatment is needed, in order to avoid its recurrence. [1]

Histologically KCOT have been classified as parakeratotic and orthokeratotic. [1],[6] These types refer to the histologic characteristics of the lining and the type of keratin produced. The orthokeratotic subtype produces keratin more closely resembling the normal keratin produced by the skin, with a keratohyaline granular layer immediately adjacent to the layers of keratin, which do not contain nuclei. The parakeratotic subtype has more disordered production of keratin; no keratohyaline granules are present, and cells slough into the keratin contains nuclei and is referred to as parakeratin. The parakeratotic type is the most frequent (80%) and has a more aggressive clinical presentation than the orthokeratotic variants. [1] The lesion reported in this case is a parakeratotic KCOT. Treatment options for KCOT are marsupilization, simple enucleation and primary closure, enucleation with the use of carnoy's solution or cryotherapy, marginal, or radical section. [8] The KCOT removed in single piece exhibited a lower recurrence frequency.The carnoy's solution is a tissue fixative that penetrates bone to a depth of 1.54 mm. Goal of using carnoy's solution is to kill epithelial remnants and dental lamina in the osseous margin. [5] We treated the lesion with enucleation and curettage along with carnoy's solution because of the high recurrence rate, and removed lesion in single piece and no recurrence was found after 1 year follow up.

The main difference between KCOT and other jaw cysts is their potential aggressive behavior, [5] recurrence is usual occurring in the first 5 year after operation. Recurrence is thought to be based on great mitotic activity and growth potential found in epithelium, therefore postoperative follow up is required. However it is difficult to diagnose the recurrence of maxillary antral cysts after surgical removal of initial lesion.

In conclusion, KCOT is relatively rare in maxillary antrum along with impacted maxillary third molar. CT is important to assessing full extent of lesion. A definitive diagnosis must be made with histopathological examination. As the lesion has high recurrence rate, we believe that accurate clinical, radiological, and surgical observation, and the use of carnoy's solution together with enucleation, curettage, or peripheral ostectomy along with follow up is necessary in order to avoid recurrence.


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