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Orthokeratinised odontogenic keratocysts in Malaysians

Siar CH, Ng KH

Br J Oral Maxillofac Surg, 1988 Jun;26(3):215-20.
PMID: 2456095

The records of the Division of Stomatology, Institute for Medical Research, Kuala Lumpur, Malaysia, were reviewed for the incidence of odontogenic keratocysts of the orthokeratinised variety, during the 20-year-period, 1967 to 1986. Nine cases were found. The clinical, histological and radiological features of these cases are reported. Many features were similar to previous reports of this entity but a peak incidence in the second decade of life, an almost even distribution in the maxilla and mandible, and a distinct predilection for the Chinese were observed. It is suggested that these features may be peculiar to Malaysians.

Matched MeSH terms: Odontogenic Cysts/pathology*
Unicystic Ameloblastoma: A Perception for the Cautious Interpretation of Radiographic and Histological Findings

Arora S

J Coll Physicians Surg Pak, 2015 Oct;25(10):761764-764.
PMID: 26454399 DOI: 10.2015/JCPSP.761764

The term Unicystic Ameloblastoma (UA) refers to those cystic lesions that show clinical and radiological characteristics of an odontogenic cyst but on histological examination show a typical ameloblastomatous epithelium lining part of the cyst cavity, with or without luminal and/or mural tumor growth. Till date, lot of controversies exist among oral surgeons and oral pathologists regarding this entity. An attempt is being made here to discuss all the diagnostic dilemmas associated with UA.

Matched MeSH terms: Odontogenic Cysts/pathology
Odontogenic keratocyst with dentinoid formation

Ng KH, Siar CH

Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 2003 May;95(5):601-6.
PMID: 12738952

Although rare, hard tissue deposits, namely dystrophic calcifications and cartilage, have been reported to occur in the connective tissue wall of the odontogenic keratocyst. However, dentinoid formation has not been previously documented. A case involving the left mandibular premolar-molar region in a 37-year-old Malay male is described here along with a brief review on the reported prevalence of hard tissue deposits in the odontogenic keratocyst. Differential diagnosis of this case from other dentinoid-forming odontogenic cysts and tumors-notably calcifying odontogenic cyst, odontoma, ameloblastic fibro-odontoma, central odontogenic fibroma and adenomatoid odontogenic tumor that may present with dentin/dentinoid formation-is discussed.

Matched MeSH terms: Odontogenic Cysts/pathology*
Fulltext Unicystic ameloblastoma: a new entity?

Zain R

Med J Malaysia, 1986 Dec;41(4):370-3.
PMID: 3670162

This article consists of two selected case reports of a recently named odontogenic tumour, unicystic ameloblastoma. The clinical and radiographic findings of the two cases mimic that of odontogenic cysts but not dentigerous cysts as in most reported, cases. Histologically, either a normal or ameloblastomatous cyst lining is evident. Other features of ameloblastoma are present within the cyst wall or as luminal nodules within the cystic space. A review of the literature indicates that this is a non-aggressive tumour with a low recurrence rate.

Matched MeSH terms: Odontogenic Cysts/pathology*
Spatial distribution of osteopontin, CD44v6 and podoplanin in the lining epithelium of odontogenic keratocyst, and their biological relevance

Kechik KA, Siar CH

Ann Diagn Pathol, 2018 Feb;32:17-22.
PMID: 29414392 DOI: 10.1016/j.anndiagpath.2017.08.002

BACKGROUND AND AIMS: The odontogenic keratocyst (OKC) remains the most challenging jaw cyst to treat because of its locally-aggressive behaviour and high recurrence potential. Emerging evidence suggests that osteopontin, its receptors CD44v6 and integrin αv, and podoplanin, have a role in the local invasiveness of this cyst. However the spatial distribution characteristics of these pro-invasive markers in the lining epithelium of OKC, and their association with the clinicopathologic parameters of OKC are largely unexplored. This study sought to address these issues in comparison with dentigerous cysts (DCs) and radicular cysts (RCs) and to evaluate their biological relevance.
METHODS: A sample consisting of 20 OKC cases, 10 DCs and 10 RCs was subjected to immunohistochemical staining for osteopontin, CD44v6 and integrin αv, and podoplanin, and semiquantitative analysis was performed.
RESULTS: All factors (except integrin αv) were detected heterogeneously in the constitutive layers of the lining epithelium in all three cyst types. Key observations were significant upregulation of CD44v6 and podoplanin in OKC compared to DCs and RCs, suggesting that these protein molecules may play crucial roles in promoting local invasiveness in OKC (P<0.05). Osteopontin underexpression and distribution patterns were indistinctive among all three cysts indicating its limited role as pro-invasive factor. Clinical parameters showed no significant correlations with all protein factors investigated.
CONCLUSIONS: Present findings suggest that an osteopontinlow CD44v6high and podoplaninhigh immunoprofile most probably represent epithelial signatures of OKC and are markers of local invasiveness in this cyst.

Matched MeSH terms: Odontogenic Cysts/pathology*
An immunohistochemical study of the lining epithelium of odontogenic keratocyst

Siar CH, Ng KH

J Nihon Univ Sch Dent, 1995 Sep;37(3):163-9.
PMID: 7490610

The lining epithelium of 15 cases of odontogenic keratocyst (OKC) was evaluated immunohistochemically. The peroxidase-antiperoxidase technique was applied to study the distribution of polyclonal keratin and S-100 protein while the indirect method was used to examine monoclonal vimentin and desmin reactivity. Consistent positive keratin staining was revealed in the lining epithelium of all 15 OKCs with additional intense staining in the stratum corneum. None of the cases showed vimentin or desmin reactivity within the lining epithelium elements. One of the 15 cysts studied showed positive S-100 protein staining in the nuclei of the lining epithelial cells. The pertinent literature on the immunophenotyping of the lining epithelium of OKC is reviewed.

Matched MeSH terms: Odontogenic Cysts/pathology*
'Combined ameloblastoma and odontogenic keratocyst' or 'keratinising ameloblastoma'

Siar CH, Ng KH

Br J Oral Maxillofac Surg, 1993 Jun;31(3):183-6.
PMID: 7685634

Four cases of either combined occurrence of ameloblastoma and odontogenic keratocyst or a rare keratinising variant of ameloblastoma are presented. The cardinal histomorphologic characteristics are simultaneous occurrence of ameloblastomatous epithelial islands with central keratinisation and multiple keratinising cysts. Immunohistochemically the tumour elements were keratin positive and occasionally S-100 protein and desmin positive. Major differential diagnosis of these neoplasms are discussed.

Matched MeSH terms: Odontogenic Cysts/pathology*
Clinicopathologic study of odontogenic keratocysts in Singapore and Malaysia

Ngeow WC, Zain RB, Yeo JF, Chai WL

J Oral Sci, 2000 Mar;42(1):9-14.
PMID: 10808269

This was a retrospective study of odontogenic keratocysts in people from the Singapore-Malaysian region. The purpose of this study was to present the clinicopathologic features of odontogenic keratocysts in the Oriental population and to compare these data with those from other reported studies. Biopsy records from 1981 to 1992 of 61 cases of odontogenic keratocysts from patients in Malaysia and Singapore showed that 42.6% of patients were female and 57.4% of patients were male. Among patients with cysts, 75.4% were Chinese, 6.6% were Malays, 9.8% were Indians and 8.2% were other ethnic groups. The mean age of these patients was 26.98 +/- 15.38 years with a peak incidence occurring in the second to fourth decades. The location of the lesions was more often in the mandible (65.5%) than the maxilla (31.0%). There was a marked predilection for lesions to occur in the posterior mandible. Histologically, 90.2% of the cysts were lined with a para-keratinized stratified squamous epithelium while only 3.3% of the cysts were lined with orthokeratinized stratified squamous epithelium. Mixed para-keratinized and orthokeratinized epithelial linings were observed in 4 cases (6.5%). The cyst linings were mainly uninflamed (95.1%). Inflammation of the cyst wall was found in 42 cases (68.8%). Twelve (19.7%) cases contained keratin in the lumen. A satellite cyst was observed in only 6 cases (9.8%). In conclusion, most clinical and histological features seen in this study were similar to those found for Caucasians. The only clinical feature that was different was the peak age incidence, that ranged from the second to fourth decades, with an absence of a second peak. Odontogenic keratocysts presenting at the site of the dentigerous cyst were observed in 7 cases (11.5%).

Matched MeSH terms: Odontogenic Cysts/pathology*
Odontogenic keratocyst: a clinical experience in Singapore

Chow HT

Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 1998 Nov;86(5):573-7.
PMID: 9830650

The odontogenic keratocyst has been well documented and extensively studied. It is of particular interest because of its high recurrence rate and aggressive nature. The material for this study consisted of 70 cases of odontogenic keratocysts in predominantly ethnic Chinese patients who were treated from 1981 to 1996. The cases were retrospectively studied to compare characteristics of the lesion in this population with those in previous reports. Most of the patients in this series were 21 to 30 years of age. Association with an impacted mandibular third molar was found in more than 50% of the cases. The recurrence rate was 20% for 35 patients with a follow-up period of at least 5 years. The follow-up period for the whole series ranged from 1 to 16 years. Treatment was surgical enucleation with peripheral ostectomy. There were no significant differences in characteristics with respect to presentation and prognosis between this series and those described in previous publications.

Matched MeSH terms: Odontogenic Cysts/pathology*
Premolar Cystic Ameloblastoma in a Child

Pathak S, Sonalika WG, Hs V, Tegginammani AS

J Coll Physicians Surg Pak, 2017 Jan;27(1):47-48.
PMID: 28292369 DOI: 2521

Mandibular swellings may occur as a result of many benign lesions of odontogenic or non-odontogenic origin. Ameloblastomas are benign tumours of odontogenic origin, whose importance lies in its potential to grow into enormous size with resulting bone deformity, it is a slow-growing, persistent, and locally aggressive neoplasm. The unicystic ameloblastoma (UA) represents an ameloblastoma variant, presenting as a cyst clinically and radiographically, but showing typical ameloblastomatous epithelium lining histologically. It commonly occurs in second and third decades of life and is rare in children under 12 years of age, and better response to conservative treatment. It shares many clinical and radiographic features with odontogenic cysts/tumours and/or periapical disease of endodontic origin. Reported here is an unusual case of unicystic ameloblastoma involving the crown of an unerupted mandibular first premolar in a 9-year boy in an uncommon location, which was misdiagnosed as periapical lesion of inflammatory origin clinically, and as a dentigerous cyst radiographically. This highlights the importance to routinely submit the removed surgical specimen for histopathological examination.

Matched MeSH terms: Odontogenic Cysts/pathology*