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Authors: Dr. Santosh Patil, Dr. Divyanshee Bishnoi


Odontogenic keratocyst, now officially known as the keratocystic odontogenic tumour requires special attention because of its aggressive biological behaviour and peculiar histological features. The tumor may occur as asymptomatic and solitary lesion, however, it may be associated with Nevoid Basal Cell Carcinoma Syndrome. The aim of this paper is to report four cases of keratocystic odontogenic tumour and highlighting its presenting features and treatment modalities.

Keywords: Keratocystic odontogenic tumour, mandible, keratocyst, bone, case report



Philipsen in 1956 described the odontogenic keratocyst (OKC), which later designated by the World Health Organization (WHO) as a keratocystic odontogenic tumour (KCOT) and is defined as “a benign uni- or multicystic, intraosseous tumour of odontogenic origin, with a characteristic lining of parakeratinized stratified squamous epithelium and potential for aggressive, infiltrative behaviour.” WHO “recommends the term keratocystic odontogenic tumour as it better reflects its neoplastic nature”.1 KCOTs occur over a wide age range with a pronounced peak incidence in the second and third decades. It is seen more frequently in males rather than in females.2


A male patient of 21 years reported with a complaint of slow growing swelling on the left side of face since 2 months which was associated with mild localized dull aching pain. Extraorally there was a large swelling over the left side of face extending from inferior orbital margin to the lower border of mandible (Figure1). The swelling was bony hard and non tender. Intraorally no relevant findings were noted. OPG (Orthopantomograph) revealed a large radiolucency extending from the mandibular left second molar tooth to involve the body, ramus and coronoid process (Figure2). Histopathological examination revealed multilayered parakeratinised squamous epithelium.


Case 2

A 42 year male reported to us with a gradually increasing swelling over right side of face since 6 months. No associated pain or parasthesia was reported. On extra oral examination a well defined swelling was seen over right side of mandible which was hard and non tender (Figure3). Intra orally obliteration of right buccal vestibule was noted (Figure4). OPG revealed radiolucency with scalloped margins extending between the roots, from the right parasymphyseal area to the body of mandible (Figure5). Histopathology revealed a cystic lumen lined by parakeratinized stratified epithelium along with keratin flecks. The epithelium was 4-8 layers thick, showed surface corrugation and focal areas separating from underlying connective tissue.


Case 3

A 27 year female presented with a complaint of swelling on left side of jaw since 3 months. Patient gave a history of swelling in the same region 3 years back which regressed after surgical treatment and later recurred. On examination a solitary swelling was noted on the left side of mandibular parasymphyseal region which was hard and moderately tender (Figure6). Intraorally a hard swelling was noted on the left side of anterior mandibular region (Figure7). OPG revealed oval radiolucency on left parasymphyseal region with smooth margins along with endodontically treated teeth with blunt apices suggesting of apicoectomy. The lesion had a central darker radiolucency surrounded by a less dense peripheral area bounded by well defined borders (Figure8). Histopathology revealed mature connective tissue exhibiting deep infiltration of epithelial islands with basal cells in picket fence appearance.



A young patient aged 12 years complained of a progressive swelling in the lower jaw since 4 months. No history of pain or parasthesia was reported. On examination a huge swelling was noted in the mandibular anterior region extraorally, which was diffuse and nontender (Figure9). Intraorally focal swelling was noted in the region of right mandibular canine and premolar (Figure10). Mandibular lateral incisor and canine were missing. Intraoral radiographs revealed a partial multilocular radiolucency with impacted lateral incisor (Figure11). OPG showed radiolucency in the mandibular symphyseal and parasymphyseal region along with displacement of anterior teeth (Figure12). Histological findings revealed a keratinizing stratified squamous epithelial layer, with palasided basal cells.



They occur most commonly in the mandible, especially in the posterior body and ramus regions. When occur in maxilla KCOTs are commonly located in the lateral incisor-canine region or sometimes in maxillary sinus.3 Mostly KCOTs are of central type and an uncommon peripheral type. Patients may complain of swelling, pain, discharge or they may be asymptomatic4. KCOTs shows characteristic clinical feature of local destruction potential and multiplying tendency when associated with nevoid basal cell carcinoma syndrome (NBCCS) or Gorlin-Goltz syndrome.5

Radiographically KCOTs are present as unilocular or multilocular lesion with corticated borders which can be scalloped. Other features include growth along the length of mandibular bone, displacement of teeth, root resorption and lingual cortical expansion.

Additional information about the lesion can be obtained with the help of computed tomography where the tumor contents usually have low attenuation typical of fluid with low concentrated protein. On magnetic resonance images, KCOT show low to intermediate signal intensity on T1- weighted images and high signal intensity on T2 –weighted images6.

Histopathologically KCOT displays thin and friable wall. Cystic lumen may contain clear fluid similar to serum transudate or may be filled with a cheesy substance consisting of keratinaceous debris. Inflammatory infiltrate findings are uncommon in this tumor. A uniform layer of stratified squamous epithelium with six to eight cells in thickness present as epithelial lining. Cyst lining epithelium may detach from the fibrous wall. Flattened parakeratotic epithelial cells are present on the luminal surface with wavy or corrugated appearance. Basal epithelial layer consist of cuboidal or columnar cells with palisade arrangement which can be hyperchromatic. Small satellite cyst, cords or islands of odontogenic epithelium may also be observed.2

The treatment of KCOT include marsupialization, enucleation and primary closure, enucleation with excision of the overlying mucosa and packing, decompression with secondary enucleation, treatment of whole cavity with Carnoy’s solution before enucleation and radical surgery.7

As the pathologic epithelium left in situ, marsupialization is not the accepted treatment for KCOT. But this can be a treatment of choice for large unilocular lesion with extremely thin lining when followed by enucleation with primary closure or packing.8

Surgically tumor can be treated conservatively or aggressively. As conservative treatment is “cyst-oriented”, it includes enucleation with or without curettage or marsupialization. It has been concluded that conservative approach can be used in all age groups, also in patients with NBCCS and it has an advantage of preservation of anatomical structures. Aggressive treatment is used when KCOT show “neoplastic nature” in NBCCS cases, large KCOTs and recurrent lesions. This modality includes peripheral ostectomy, chemical curettage with Carnoy’s solution or en block resection.9

OKCs differ from other jaw tumors by their potential aggressive behavior ranging from 5% to 62.5%.10 Recurrence of cyst can be due to incomplete removal of cyst lining, growth of new KCOT from satellite cyst and development of new KCOT in an adjacent area.11 Following surgery postoperative follow up with annual radiological examination is essential.12 Tumor can recur even after 10 year follow-up and treatment. Due to difficulty in removal of the tumor from the ramus KCOT may have higher tendency of recurrence in the angle and ramus region of mandible as compared to those occurring in the body13. Along with this another aggressive biological potential of KCOT is malignant transformation, 12 cases in this series have been reported in the literature.14


The biological nature of KCOT requires an aggressive treatment and the recent reclassification of KCOT by WHO as a neoplasm motivate clinicians in this direction. Although recurrence rate is noted lowest in resection, considering the radical nature of the procedure, unless resection is necessary, it is advantageous to use enucleation in combination with Carnoy’s solution or marsupialization. With continuation of research, treatment may become molecular in nature. This could eliminate the need for aggressive management of lesion. The consideration of the OKC as a tumor and the research that influenced this change will greatly influence the future treatment plans for the same.

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  14. Keszler A, Piloni MJ. Malignant transformation in odontogenic keratocysts. Case report. Medicina Oral 2002; 7: 331-35.

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