Odontogenic Keratocyst in Right Maxilla of 15 Year Old Boy : A Case Report of not a Rare Lesion

Wepresent a case of odontogenickeratocyst involving the right maxilla in 15 years old boy. The histochemicalof the lesion was analysed by haematoxylin & eosin stain and picrosirius red stain.Expansilenatureof the lesion was assessed by using picrosirius red to categorize the fibrous wall of the cyst. The purpose of this case report is to stressthe point that even though the diagnosis of classical odontogenickeratocystis straight forward with histochemical study alone, it is prudent to profile the biology of each patient using less expensive methods before deciding the appropriate adjunctive surgical procedure,for proper rehabilitation of that particular patient as well as to avoid its recurrence in future.


INTRODUCTION
The odontogenickeratocystis distinctive among various odontogenic cysts due various factors such as distinct histological findings, aggressive clinical behaviour and increased recurrence rate.It is mostly seen 2 nd -3 rd decade of life with slight female predeliction. 1It is seen predominantly in mandible (around 78%) and mostly in ramus-third molar area.Clinical presentation varies frombeing asymptomatic to pain, soft-tissue swelling, bone expansion etc. 2 Radiologically it usually unilocular with welldeveloped sclerotic borders, however it mimics other lesions in most cases like periapical cyst. 3In the treatment respective, there is always a dilemma between conservative surgical excision and the resection of the lesion with adjacent bone, to prevent recurrence. 4So many research have been done on the molecular biology and genetic aspect of odontogenickeratocyst using histochemical, immunohistochemical, genetic engineering etc, to understand its pathogenesis and substantiate the term called 'keratocysticodontogenic tumour'. 5ing eosin and haematoxylin stain, changes in typical characters of linning epithelium of odontogenickeratocyst is assessed.Special stain, picrosirius red is used to stain collagen present fibrous wall subsequently to assess influence of inflammation on linning epithelium and fibrous wall as well as categorize the collagen fibres to predict the expansile nature of cyst. 6Hence in this case report we are created a separate profile for the patient by doing immunohistochemical and special stains to decide the subsequent treatment option for this particular patient.

Case report
A 15 year old boy came to our department with the chief complaint of tooth painon right side of the upper jaw for past 2 months.Extra oral examination was unremarkable.On intraoral examination no swelling detected around 14 region.Tooth 14 was vital.Radiographically a well demarcated radiolucency without corticated margin is found periapical to 14.A full thickness flap is elevated and a cystic lesion of 2 cm x 1.5 cmwasseen perforating the palatal cortical plate.The lesion was enucleated and submitted for histological examination.(Fig.1) The provisional diagnosis of periapical cyst was considered.
On histologic examination, using eosin and haematoxylin it showed a cystic lesion linned by epithelium which is parakeratinizedcorrugated stratified squamous variant of uniform thickness in most of the areas and foci of inflammatory cell infiltration were also seen.Thelinning epithelium showed palisaded basal layer containing hyperchromatic nuclei.Linning epithelium corresponding to inflammatory foci has changed to non-keratinized form.The rete process is absent.Finally it is

DISCUSSION
Odontogenickeratocyst is a distinctive histopathological type of developmental odontogenic cysts. 7In 1956, it was first described as odontogenickeratocyst by Philipsen.Finally it was renamed by Philipsen as kerato cysticodontogenic tumor and reclassified under the lesions of odontogenic neoplasm according to odontogenic tumours classification given by World Health Organization in 2005. 8Remnants of basal lamina and basal cells proliferating from the overlying epithelium are two main sources of origin for odontogenic keratocyst. 9Important step in pathogenesis of odontogenickeratocyst is the mutation of gene PTCH a tumour suppressor gene and supported its tumour like behavior. 10ontogenickeratocyst shows more number of cases are seen between 40-50 age groups. 2 Odontogenic keratocyst was more frequent in male compared to female. 9Mandibular molarramus area is the most common site for odontogenic keratocyst. 11In case of maxilla, most frequently involved site is third molar area and next is cuspid region. 1 Odontogenic keratocyst will be asymptomatic in most cases.The lesion are diagnosed later in life and usually attain larger size as they grows mainly through medullary space of the jaw in antero-posterior direction. 12That usually odontogenickeratocyst which are smaller in size are asymptomatic and discovered only in radiographic examination.Pain and swelling are mostly seen with larger lesions only. 2 In maxilla, it may extend up to maxillary antrum. 13aller lesions are usually seen as radiolucent lesion with well-defined lamina dura. 14That 40% of odontogenickeratocyst are seen as unilocular lesions adjacent to crown of the teeth. 1 Radiographic features of scalloped margin and multilocular appearance seen in odontogenickeratocyst are indicative, but these features are also seen in other odontogenic lesions. 15Histological features includes 5-8 rows of thin epithelium without rete pegs, predominant parakeratosis surface layer with wavy appearance, a basal layer made up of columnar or cuboidal cells with palisaded, thin layer of vacuolated cells of stratum spinosum and a fibrous capsule which is thin and devoid of inflammatory cell infiltration. 16The basal layer is characterized by columnar or cuboidal cells showing palisaded hyperchromatic nuclei showing reversal of polarity.The surface epithelium is usually corrugated.The cystic lumen is filled with desquamated squamous or necrotic material. 17Fibrous capsule which is usually thin with decreased cellularity often separated by stroma.This stroma is rich in mucopolysaccharide with rare infiltration of inflammatory cells like lymphocyte and monocytes.If there is inflammatory infiltration, the adjacent epithelium thickens and develops rete process.The weak attachment between the epithelium and the connective tissue result in their separation.The cyst wall is mostly seen collapsed and folded. 9scribed the presence of satellite cyst within the wall, which may be the reason for its higher recurrence rate. 18Odontogenic keratocyst showed higher recurrence rate ranging from 5% -62% with most cases encountered in posterior body and ascending ramus area of mandible. 2Treatment modalities of odontogenickeratocyst which includes surgical treatment characterized by enucleation with peripheral ostectomy. 9ing picrosirius red stain, collagen structure can be studied under polarization microscope.under them, collagen takes different  based on fibre thickness, packing and arrangement of collagen fibres. 18Under polarization microscope, thin normal collagen fibres as well as poorly packed fibres are green to greenish yellow, whereas thick fibres as well as well packed fibres range from yellowish orange through orange to red. 19,20 our case fibrous wall of odontogenickeratocyst showed predominantly yellowish orange fibre, which in correlation with finding found byAggarwal P et al.This indicates that predominantly tight packed fibres are present in the fibrous wall.Similar fibres are also seen in stroma of odontogenic tumours like ameloblastoma. 21Hence it can be concluded that aggressive behaviour of odontogenickeratocyst is also derived from its well-organized stroma.But our case result contradicts with the results given by Hirshberg A et al, 18 as he showed odontogenickeratocysts predominantly showed greenish yellow collagen fibres under polarizing microscope.
It also found that areas of fibrous wall corresponding to inflammatory cell infiltration showed greenish yellow fibres, hence it should be made up of predominantly thin and less organized fibres suggestive of procollagen or pathologic collagen.The presence of such fibres may be due to the dense infiltration of inflammatory cells in this cyst wall which releases abundant cytokines, endotoxins and lymphokines into the surrounding connective tissue as well as shows increased collagenase activity in the stroma.All these factors results in the degradation of the extracellular matrix. 22As most of the areas showed tightly packed fibrous wall, this case is considered as aggressive and followed up for recurrence.But in 2 years follow up, it is uneventful.Hence before doing expensive investigation, which consumes valuable time, it isbetterto do special stain like picrosirius red which is outdated but less technique sensitive.In doing so we are able to additional information regarding in aggressive nature and decide the treatment plan accordingly.