|DENTAL SCIENCE - ORIGINAL ARTICLE
|Year : 2014 | Volume
| Issue : 5 | Page : 127-130
Prevalence and clinicopathological comparison of kerotocystic odontogenic tumor and orthokeratinized odontogenic cyst in South Indian sample population: A retrospective study over 13 years
Manickam Selvamani1, Andamuthu Yamuna Devi2, Praveen S Basandi1, GS Madhushankari1
1 Department of Oral and Maxillofacial Pathology and Microbiology, College of Dental Sciences and Hospital, Davangere, Karnataka, India
2 Department of Oral Pathology, Vivekanandha Dental College for Women, Tiruchengode, Namakkal, Tamil Nadu, India
|Date of Submission||30-Mar-2014|
|Date of Decision||30-Mar-2014|
|Date of Acceptance||09-Apr-2014|
|Date of Web Publication||25-Jul-2014|
Dr. Manickam Selvamani
Department of Oral and Maxillofacial Pathology and Microbiology, College of Dental Sciences and Hospital, Davangere, Karnataka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Aim and Methodology: The purpose of this study is to determine the prevalence of keratocystic odontogenic tumor (KCOT) and orthokeratinized odontogenic cyst (OOC), to identify their clinicopathological features among the patients by studying the biopsy specimens obtained from the archives of the Department of Oral and Maxillofacial Pathology, College of Dental Sciences, Davangere, Karnataka, India during the period of 2001-2013. Data for this study is retrieved from the case records of the patients fitting the histological classification of the World Health Organization (2005). The following clinical variables, namely age, gender, anatomical location, and histological features are analyzed. Results: Of the 3026 biopsy reports (100%) present in the archives, we had 31 cases (1.02%) of KCOT, 11 cases (0.36%) of OOC and a combination of para and orthokeratinized lining epithelium made 1 case (0.033%). The most frequent clinical manifestation was asymptomatic followed by the combination of pain and swelling. The male: female ratio was 1.4:1 with a mean age of 30 years in KCOT, while 2.7:1 with a mean age of 29.1 years in OOC. Posterior molar-ramus region was most commonly involved in both KCOT and OOC. Conclusion: Due to aggressiveness and high recurrence rate of KCOT, differentiation between KCOT and OOC is important, with respect to their treatment modalities. Such epidemiological pools are also essential for the analysis of geographical distribution of odontogenic tumours
Keywords: Keratocystic odontogenic tumor, orthokeratinized odontogenic cysts, World Health Organization
|How to cite this article:|
Selvamani M, Devi AY, Basandi PS, Madhushankari G S. Prevalence and clinicopathological comparison of kerotocystic odontogenic tumor and orthokeratinized odontogenic cyst in South Indian sample population: A retrospective study over 13 years. J Pharm Bioall Sci 2014;6, Suppl S1:127-30
|How to cite this URL:|
Selvamani M, Devi AY, Basandi PS, Madhushankari G S. Prevalence and clinicopathological comparison of kerotocystic odontogenic tumor and orthokeratinized odontogenic cyst in South Indian sample population: A retrospective study over 13 years. J Pharm Bioall Sci [serial online] 2014 [cited 2019 Nov 14];6, Suppl S1:127-30. Available from: http://www.jpbsonline.org/text.asp?2014/6/5/127/137418
Kramer (1974) has defined a cyst as "a pathological cavity having fluid, semifluid or gaseous contents and which is not created by the accumulation of pus." Most cysts, but not all, are lined by epithelium.  Odontogenic cysts constitute an important aspect of oral and maxillofacial pathology as they are encountered relatively common in dental practice. An odontogenic cyst is developmental in origin, when any of the odontogenic cell rests such as, epithelial remnants of Malassez, cell rests of Serres, or the enamel organ gets activated and proliferates within the bone tissue or gingival tissue of the jaws. Inflammatory odontogenic cysts are formed due to activation of these cell rests by an inflammatory process. 
Developmental odontogenic cysts and inflammatory odontogenic cysts are of epithelial origin and exhibits slow growth and a tendency toward expansion. However, these lesions in spite of being benign in biological behavior, they can reach a marked size if they are not diagnosed in time and treated appropriately.  Few odontogenic cysts such as odontogenic kerato cyst (OKC) (renamed as keratocystic odontogenic tumor [KCOT]) exhibits locally aggressive behavior and are prone to recurrence. Therefore, the correct diagnosis of these lesions is essential for correct surgical treatment and ensuring adequate follow-up.
In 2005, the World Health Organization (WHO)  designated OKC as KCOT and is defined as "a benign uni- or multi-cystic, intra-osseous tumor of odontogenic origin, with a characteristic lining of a parakeratinized stratified squamous epithelium and potential for aggressive, infiltrative behavior." The orthokeratotic type, which is now recognized as an entirely separate lesion, is represented by the terminology, orthokeratinzed odontogenic cyst (OOC).  The significant variation in the clinical aggressiveness, pathogenesis and prognosis of the ortho- and para-keratinized variants of OKC, made it vital to re-classify them as two separate entities.
Information regarding the demographic profile of these two lesions in different population is very limited, especially in the Indian population. Thus, the objective of this study was to re-classify and to check the distribution, clinical, radiological, and histological aspects of both KCOT and OOC in Davangere and its surrounding population of Karnataka, India.
| Materials and Methods|| |
A retrospective search was conducted in the archives of Department of Oral Pathology and Microbiology, College of Dental Sciences, Davangere between 2001 and 2013. The cases diagnosed as OKC, inclusive of both the variants were selected for the study, based on final histopathological reports. Data regarding age, gender, and anatomic location of all cases were compiled from the clinical data sent together with the biopsy records. Hematoxylin and eosin stained histopathological slides of the selected cases, diagnosed as OKC and/or its variant were reevaluated by three pathologists according to current concepts, as outlined in the 2005 WHO histologic classification. 
The inclusion criteria involved histological confirmation of OOC and KCOT. The following variables were recorded: Gender, age, radiological findings, and location of the lesion. The following anatomic sites were defined: Maxilla, anterior maxilla, posterior maxilla, anterioposterior maxilla, mandible, anterior mandible, posterior mandible, and anterioposterior mandible. Anterior was defined as canine to canine region and posterior was defined as premolar and molar region including ramus of mandible while anterioposterior defined as involving both anterior and posterior segment.
Nevertheless, some records sent together with the biopsy material were incomplete and excluded from the study, in order to assure the most reliable epidemiological profile of odontogenic cysts in our population.
The collected data were subjected to descriptive statistical analysis with the SPSS version 16.0 statistical software package (SPSS Inc., Chicago, USA).
| Results|| |
Among the 3026 oral biopsy specimens (N = 3026) retrieved, we found 31 cases (1.02%) of KCOT, 11 cases (0.36%) of OOC and 1 case with both para- and ortho-keratinized lining epithelium (0.033%) [Table 1].
|Table 1: Prevalence of KCOT, OOC, and combination of ortho- and para-keratinization type|
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Age and gender
Of all of the KCOT (n = 31), 18 cases (58.1%) were observed in men and 13 cases (41.9%) were seen in women, with male: female ratio of 1.4:1. The mean age was 30 years (range: 11-80 years), with 11 cases (35.5%) and 8 cases (25.8%) being diagnosed in the second and third decades of life, respectively. While OOC analysis (n = 11) revealed that, 8 cases (72.7%) were observed in men and 3 cases (27.3%) were seen in women, with a male: female ratio was 2.7:1. The mean age of the presentation was 29.1 years (range: 20-46 years), and 7 cases (63.6%) were seen in the second decade and 2 cases (18.2%) in the first decade of life. A single case showing the combination of para- and ortho-keratinized variant was seen in a 44-year-old male patient [Table 2] and [Table 3].
|Table 2: Distribution of KCOT, OOC and combination of ortho- and para-keratinization type by age|
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|Table 3: Distribution of KCOT, OOC and combination of ortho- and para-keratinization type by gender|
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Of the 31 KCOT, 25 cases (80.6%) were on the mandible and 6 cases (19.4%) were on the maxilla. In the mandible, the most commonly affected site was the posterior region including the ramus of mandible (13 cases, 52%), whereas in the maxilla, it was equally distributed among the anterior, posterior, and anterioposterior regions. In case of OOC, 9 cases (81.8%) were on the mandible and 2 cases (18.2%) on the maxilla. In the mandible, the most commonly affected site was the posterior region including the ramus of mandible (5 cases, 55.6%), while it was anterior region in the maxilla [Table 4].
|Table 4: Distribution of KCOT, OOC and combination of ortho-and para-keratinization type in maxilla and mandible|
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| Discussion|| |
Odontogenic keratocyst arising from the remnants of dental lamina, is the third most common type of odontogenic cyst in a study from Indian sample population.  In 2005, the WHO  gave a new classification for odontogenic tumors, renaming parakeratinized variant of OKC as KCOT. It is an unusual odontogenic cyst with tumor nature due to its unique clinical aggressive behavior, marked tendency to recur, high mitotic count and greater epithelial turnover rate. In the present study, we compared the prevalence and clinical presentation of KCOT (31 cases), OOC (11 cases) and lesion with combination of para- and ortho-keratinized lining epithelium (1 case).
Prevalence of KCOT (1.02%) is more than OOC (0.36%) similar to the findings of another study from Indian population,  but prevalence rate varies between the two studies, which may be due to the discrepancy in sample size.
In this study, KCOT shows male predominance with a male: female ratio was 1.4:1 similar to other studies available in English literature. , Other clinical presentations of KCOT in this study are seen frequently in the third decade of life (mean age 30 years) and at posterior mandibular region, which is again similar to most others studies. ,,,, OOC, on the other hand, show male predominance with a male: female ratio was 2.7:1, consistent with other study result,  with mean age of diagnosis being 29.1 years. It occurs more frequently in mandible, that too in the molar-ramus region, similar to the findings of Dong et al.  and Kotwaney and Shetty. 
Histologically all our KCOT showed parakeratinized stratified squamous epithelial lining with palisaded layer of basal cells and surface corrugation with uniform thickness of 6-10 layers. Separation between the connective tissue and overlying surface epithelium, presence of satellite cyst, odontogenic epithelial islands, cholesterol cleft and giant cells are also seen in few KCOT cases. WHO 2005  also highlights on the nuclei of the basal columnar cells, which tends to be oriented away from the basement membrane with characteristic "picket fence" or "tombstone" appearance and are often intensely basophilic, which is an important feature in distinguishing KCOT from other jaw cysts with keratinization. Presence of mitotic figures in the suprabasal layers can be observed, but malignant transformation to squamous cell carcinoma is rare. 
Orthokeratinized odontogenic cyst showed features of orthokeratinized stratified squamous epithelium with 4-6 layer thickness. It showed prominent stratum granulosum, and low cuboidal or flattened basal layer and the lumen was filled with keratin. Only one case showed the combination of para- and ortho-keratinized stratified squamous epithelial lining with palisaded layer of basal cells. Surface epithelium showed corrugation with uniform thickness.
| Conclusion|| |
Our study results analyzing the distribution of KCOT and OOC for more than a decade could act as a viable record for the distribution of these odontogenic lesions in our sample population. With reclassification by WHO 2005, the aggressive nature of KCOT requires site and size based treatment, ranging from simple enucleation or marsupialization, with Carnoy's solution up to radical excision while OOC, on the other hand, is less aggressive and requires conservative treatment preferably. Thus, the knowledge of the clinical and histological behavior of these odontogenic tumor and cyst, gained through various epidemiological study pools, is needed to ensure early detection and prompt treatment for these lesions.
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[Table 1], [Table 2], [Table 3], [Table 4]