Journal of Advanced Clinical and Research Insights

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Keratocystic odontogenic tumor
Keratocystic odontogenic tumor
Anjani Kumar Jha1, Nonitha S2, Tejavathi Nagaraj3, Hema Keswani2, Sarvesh Vijay2
1Department of Dentistry, Narayan Medical College & Hospital, Jamuhar, Rohtas, Bihar, India
2Department of Oral and Maxillofacial Pathology, Sri Rajiv Gandhi College of Dental Sciences and Hospital, Bengaluru, Karnataka, India
3Department of Oral Medicine and Radiology, Sri Rajiv Gandhi College of Dental Sciences and Hospital, Bengaluru, Karnataka, India
Correspondence: Department of Oral and Maxillofacial Pathology, Sri Rajiv Gandhi College of Dental Sciences and Hospital, Bengaluru, Karnataka, India.
Phone: +91-8123041469
Received 29 December 2017;
Accepted 22 February 2017
doi: 10.15713/ins.jcri.198
Odontogenic cysts are considered as non-neoplastic benign lesions. Odontogenic keratocyst is a cystic lesion of tooth origin with an intrusive clinical behavior involving an elevated recurrence rate. It has been renamed to keratocystic odontogenic tumor (KCOT), as it explains its tumor nature which is distinguished by stratified squamous epithelium with parakeratinization and a prospective for destruction, impregnating behavior, and for the possibility for malignant transformation in the wall of the lesion. Histologic examination is necessary for diagnosis as the clinician find it difficult to manage the lesion since the true nature of the lesion is not revealed. This article is an attempt to extend an outline of a diverse strand of KCOT.
Keywords:Benign tumor,odontogenic tumor,PTCH, satellite cyst
How to cite this article: Jha AK, Nonitha S, Nagaraj T, KeswaniH, Vijay S. Keratocystic odontogenic tumor. J Adv Clin ResInsights 2018;5:15-17.


Originally recounted by Philipsen in 1956, the odontogenic keratocyst (OKC) is now nominated by the World Health Organization (WHO) as a keratocystic odontogenic tumor (KCOT) and 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."[1]

WHO "endorse the title KCOT, as it imitates its tumor nature." KCOT possibly contemplate as a benign tumor rather than a traditional cyst depending on its clinical behavior (Toller 1967).[2]

Ahlfors et al. proposed that "if OKC was identified as an actual, benign cystic epithelial tumor, the query of advanced treatment modalities has to be answered."[3] Harring et al. designated this cystic lesion by declaring that "After more than 30 years of research, the aspects of KCOT in terms of histogenesis, pathogenesis, histology, high recurrence rate, and malignant possibility are still being puzzled."[4] The WHO reclassified OKC as a tumor.
  • Behavior: As proposed before, the KCOT is regionally catastrophic and eminently recurrent in nature.
  • Histopathology: KCOT is characterized by budding of basal layer into connective tissue and mitotic figures in the suprabasal layers.[5]
  • Genetics: PTCH ("patched"), a tumor suppressor gene intricate in both nevoid basal cell carcinomas (NBCCS) and sporadic KCOTs, usually diverse a receptor complex with oncogeneSMO ("smoothened") for the SHH ("sonic hedgehog") ligand. PTCH attaching to SMO obstructs growth-signal transduction. The bond between SHH and PTCH releases this inhibition. If the normal functioning of PTCH is off-track, the proliferation-stimulating effects of SMO are allowed to prevail.[6]

KCOT is a benign growth of odontogenic origin with a probable destructive and penetrating behavior. It is most predilicted in mandible and manifests a unilocular, round, oval, scalloped radiolucent area, while huge lesions may show multilocular areas.[7] A prime feature of KCOT is its proclivity to spread in an anterior to posterior direction.[2] The aggressive behavior of KCOT to the extent that they impale cortical bone and involved surrounding soft tissues have been reported. According to (Browne, 1971), he showed that after the removal of KCOT the recurrence rate with satellite cysts was 23.7% and those without satellite cysts was 24.4%.[2]

Possible reasons for recurrence are:
  1. Insufficient eviction of the native cyst's lining.
  2. Spread of a new lesion from tiny satellite cysts of odontogenic epithelial rests left behind after the surgical treatment.
  3. Evolvement of an unrelated KCOT in an adjoining radius of the jaws, which is interpreted as a reappearance.[8]

Case Report

A 32-year-male came with a swelling on the right side of the face since 8 months. On extra-oral assessment, facial asymmetry wasobserved toward the right side of mandible [Figure1]. Intra-oralswelling was present on the right lower vestibular area measuringaround 1.5 cm × 3 cm with obliteration. On palpation, theswelling was soft to firm in consistency. Provisional diagnosiswas given as KCOT with differential diagnosis of ameloblastoma.

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Jha, et al. Keratocystic odontogenic tumor

Panoramic radiograph revealed radiolucency with respect to45 extending till angle and condylar region of the mandible. Themargins were sclerotic [Figure 2]. An excisional biopsy specimenwas consigned for histopathological evaluation [Figure 3].

Histopathological findings

The H and E stained soft tissue section shows cystic, corrugatedparakeratinized stratified squamous epithelium of 6-8 layerthickness with characteristic basal cell palisaded arrangement.The capsular connective tissue is mainly composed of fibroustissue. Separation of epithelium from connective tissue is seenat the focal area. Scanty inflammatory infiltrate is also seen in thecapsular tissue wall [Figures 4 and 5]. The presence of satellitecysts was noted in few areas [Figure 6].

Keratocystic odontogenic tumor
Figure 1: Extra-oral view with slight swelling on the right side ofthe mandible

Keratocystic odontogenic tumor
Figure 2: Panoramic radiograph revealed radiolucency with respectto 45 extending till angle and condylar region of mandible

Based on clinical, radiographical and histopathologicalfindings, the final diagnosis was concluded as KCOT.


Philipsen in 1956 was the first person to give the description of OKChistologically for all the cysts that showed keratinization. Pindborgand Hansen 1963 concluded the histological criteria, which were laterconfirmed by Browne in the year 1970 and 1971. KCOTs incorporatealmost 11% of all cystic lesion of the jaws. They appear frequently in thelower jaw region, specifically in the posterior body and ramus.[2] Thecase reported here also shows the same site predilection. KCOT as amatter of course generally effect bone, but a few cases with peripheralKCOT have also been published in the English literature. Patients maycomplain of swelling, pain, and discharge or may be asymptomatic innature[9] whereas our patient reported with asymptomatic swelling.KCOT has many differentiating clinical and histologic featureswhich includes: (i) Prospect for provincially devastative manner; (ii)comparatively more recurrence rate, and (iii) titled as a undeviatingfinding in the NBCCS syndrome, or Gorlin syndrome. It is mostfrequently reported in the second, third, and fourth decades of life atthe posterior lower jaw region in case of male patients. The features ofthe reported case are also in concurrence with the previous reportedcases. The radiographic finding of KCOT includes unilocular ormultilocular lesion. Tiny unilocular cystic lesions can be startled withperiapical, dentigerous, lateral periodontal cysts or gingival cysts, andhuge unilocular KCOT can resemble ameloblastoma. A unilocularKCOT appears as a radiolucent lesion with well-defined margins.Resorption of root, eviction of erupted tooth or migration of impactederupted teeth may be obvious.[2,5]

Keratocystic odontogenic tumor
Figure 3: Macroscopic picture of the obtained specimen

Keratocystic odontogenic tumor
Figure 4: The H and E stained histological section shows cysticlining with lumen corrugated epithelium with budding into theconnective tissue [Low power]

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Keratocystic odontogenic tumor Jha, et al.

Keratocystic odontogenic tumor
Figure 5: Basal cells of epithelium showing tall columnar polarizedcells with palisaded or tombstone appearance [high power]

Keratocystic odontogenic tumor
Figure 6: Daughter/satellite cyst into the connective tissue [highpower]

On microscopic assessment, KCOT shows invariableparakeratinized epithelium with corrugation, thick cellsshowing a flat basal surface lining called the fibrous wall. Thecystic chamber is bounded with a slim coating of connectivetissue roofed by stratified squamous epithelium which is eitherorthokeratinized or parakeratinized in nature.[5,8]

Morgan et al., 2005 classified surgical regimen for KCOTas moderate or assertive. The moderate management is "cystoriented"and thus comprises enucleation, with or withoutcurettage, or marsupialization. The convenience is maintenanceof anatomy. Assertive treatment approaches the "tumor nature"of the KCOT and constitutes peripheral ostectomy, chemicalcurettage with Carnoy's solution or en bloc resection. As perliterature review, the recurrence rate is proportionately lowwith assertive management, whereas more moderate methodgravitate to outcome high recurrence rate.[10]

Clinical significance

KCOTs have a more reversion rate, observed ranging from 25%to 60%.[5] The Angle of mandible and Ramus are the areas inthe mandible where vision is compromised at the operative fieldbecause of its anatomical site, which results in the incompleteremoval of tumor, which causes subsequent recurrences.[9] Hence,the proper diagnosis and management of KCOT are necessary.

  1. Abdullah WA. Surgical treatment of keratocystic odontogenictumour: A review article. Saudi Dent J 2011;23:61-5.
  2. Shear M, Speight P. Cysts of the Oral and Maxillofacial Regions.4th ed. Oxford: Blackwell Publishing Ltd.; 2007.
  3. Ahlfors E, Larsson A, Sjogren S. The odontogenic keratocyst:A benign cystic tumor? J Oral Maxillofac Surg 1984;42:10-9.
  4. Haring JI, Van Dis ML. Odontogenic keratocysts; A clinical,radiographic and histopathologic study. Oral Surg Oral MedOral Pathol 1988;66:145-53.
  5. Thompson L. World health organization classification oftumours: Pathology and genetics of head and neck tumours. EarNose Throat J 2006;85:74.
  6. Madras J1, Lapointe H. Keratocystic odontogenic tumour:Reclassification of the odontogenic keratocyst from cyst totumour. J Can Dent Assoc 2008;74:165-h.
  7. Nair KK, Lingappa A, Rangaiah P, Vittobarao PG. Keratocysticodontogenic tumor: A case report and review of literature.J Indian Acad Oral Med Radiol 2015;27:253-8
  8. Singh M, Gupta KC. Surgical treatment of odontogenickeratocyst by enucleation. Contemp Clin Dent 2010;1:263-7.
  9. Fidele NB, Duan F, Kazadi EK, Guan J, Augustin MM, Zhou Y.Keratocyst odontogenic tumor: Treatment methods at the secondaffiliated hospital of Jiamusi University. Open J Stomatol 2015;5:251-8.
  10. Shah K, Mistry J, Koppikar R, Karagir A. Keratocysticodontogenic tumor: Current concepts, theory and presentationof two contrasting cases. IOSR J Dent Med Sci 2013;9:49-53.

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