MyMedR

Peripheral odontogenic fibroma with clear cell odontogenic epithelium

Siar CH, NG KH

J N Z Soc Periodontol, 1995.

The clinical and histological features of the peripheral odontogenic fibroma are briefly outlined. A case arising from the attached lingual gingiva between the mandibular right permanent first molar and the second molar in a 67 year old Indian female is reported here. The unusual occurrence of marked clear cell differentiation within the odontogenic epithelial component, and histogenetic link to the clear cell rests of the dental lamina and surface epithelium are discussed.

Matched MeSH terms: Odontogenic Tumors/pathology*

The combined epithelial odontogenic tumour in Malaysians

Siar CH, Ng KH

Br J Oral Maxillofac Surg, 1991 Apr;29(2):106-9.

PMID: 2049349

The combined epithelial odontogenic tumour represents a hybrid lesion comprising primarily areas of adenomatoid odontogenic tumour intermixed with foci of calcifying epithelial odontogenic tumour. Five such cases retrieved from the files of the Division of Stomatology, Institute for Medical Research, Kuala Lumpur, and four others from the existing literature were analysed. A mean age of 18.8 years, a female preponderance (66.7%) with a male to female ratio of 1:2 and predilection for the mandible (55.6%) were observed. All cases were treated by conservative surgery and the lack of recurrence confirmed the innocuous nature of this lesion.

Matched MeSH terms: Odontogenic Tumors/pathology*

Plexiform granular cell odontogenic tumor: unicystic variant

Siar CH, Ng KH, Jalil NA

Oral Surg. Oral Med. Oral Pathol., 1991 Jul;72(1):82-5.

PMID: 1891247

Plexiform granular cell odontogenic tumor of the mandible has recently been described. The cardinal histopathologic feature, as its name suggests, is a monophasic plexiform pattern of granular cells; the principal tumor in the differential diagnosis is granular cell ameloblastoma. Unlike the two previously reported cases of plexiform granular cell odontogenic tumor, which occurred as solid tumors in elderly men, the lesion reported here is a unicystic variant occurring in a middle-aged woman.

Matched MeSH terms: Odontogenic Tumors/pathology*

Combined granular cell ameloblastoma and plexiform granular cell odontogenic tumour

Siar CH, Ng KH, Chia TY

Singapore Dent J, 1990 Dec;15(1):35-7.

PMID: 2097728

Granular cell ameloblastomas are uncommon lesions accounting for about 3-5% of all histologic subtypes of ameloblastoma. The plexiform granular cell odontogenic tumour, on the other hand, is a newly described lesion characterised by a monophasic plexiform pattern of granular cells. This article reports a tumour found occurring in the left mandible of a 67-year-old Indian male which histologically showed features of both the aforementioned lesions.

Matched MeSH terms: Odontogenic Tumors/pathology*

Fulltext Acanthomatous ameloblastoma in anterior mandibular region of a young patient: A rare case report

Ugrappa S, Jain A, Fuloria NK, Fuloria S

Ann Afr Med, 2017 Apr-Jun;16(2):85-89.

PMID: 28469123 DOI: 10.4103/aam.aam_51_16

Ameloblastoma is the most known of the epithelial odontogenic benign tumor. It is slow growing and locally aggressive in nature and most commonly seen in the posterior mandible. Various histopathological variants exist, among which acanthomatous type of ameloblastoma is one of the rarest types. Acanthomatous ameloblastoma is usually seen in older aged human population and most commonly reported in canine region of dogs in literature. Here, we report a rare case of acanthomatous ameloblastoma in a young male patient involving mandibular anterior region crossing the midline with recurrence over a period of 2 years of follow-up after surgical resection.

Matched MeSH terms: Odontogenic Tumors/pathology*

A clinicopathologic study of 173 odontogenic tumours in Northern Peninsular Malaysia (2007-2014)

Ismail S, Saw CL

Malays J Pathol, 2018 Aug;40(2):129-135.

PMID: 30173229 MyJurnal

INTRODUCTION: The objectives of this study were to analyse, compare and contrast the demographic, clinical and pathological data of odontogenic tumours seen at a regional oral pathology centre in the Northern part of Peninsular Malaysia with other international data as an aid to clinicians in diagnosing odontogenic tumours.

MATERIALS AND METHODS: This was a descriptive, retrospective study of odontogenic tumours diagnosed from January 2007 to December 2014 at this centre. The odontogenic tumours were classified using the 2005 World Health Organization classification system.

RESULTS: Among 2,733 biopsy specimens, 173 cases were diagnosed as odontogenic tumours (6.3%), of which 171 (98.8%) are benign and 2 (1.2%) are malignant. The most frequently encountered tumour was ameloblastoma (n=96, 55.5%), followed by keratocystic odontogenic tumour (KCOT) (n=38, 22.0%) and odontomas (n=16, 9.2%). Malignant tumours accounted for 1.2% of the tumours. Most ameloblastomas and KCOTs affected the mandible preferentially. The mean age was 33.5 (± 17.8) years and 64.7% of patients were in the age group of 10 to 39. Odontogenic tumours were slightly more common in males, with a male to female ratio of 1.4:1.

CONCLUSION: The findings of this study are similar to the other studies in Asia in which the most common tumour encountered is the ameloblastoma, followed by KCOT. The most common signs and symptoms are pain and swelling, while paraesthesia and root resorption are less frequently reported. Such clinical and radiographic features should alert the clinician of a possible odontogenic tumour and though rare, malignant tumours should also be included in the differential diagnoses.

Matched MeSH terms: Odontogenic Tumors/pathology*

Granular ameloblastoma: report of two cases with atypical cytological aspects

Arora S, Urs AB, Kumar P, Augustine J, Saran RK

Rom J Morphol Embryol, 2017;58(3):997-1001.

PMID: 29250680

Ameloblastoma is an aggressive odontogenic tumor, which arises from odontogenic epithelium. Ameloblastomas can present in several clinical and histomorphological patterns. The granular cell variant accounts for only 3.5% to 5% of ameloblastomas. We have presented two cases of granular cell ameloblastoma (GCA) occurring in a 44-year-old and 50-year-old man, respectively. Case No. 1 on incisional biopsy was diagnosed as unicystic ameloblastoma (UA), which later after excisional biopsy was finally diagnosed as GCA owing to the features observed in excisional biopsied tissue. Case No. 2 on incisional biopsy showed darker and lighter stained cells arranged in small follicular pattern, and anastomosing cords. Meticulous immunohistochemistry, histochemical examination and careful literature search helped us to diagnose it as GCA. We have made an attempt to elucidate the diagnosis of GCA especially in cases of GCA with unusual granular component.

Matched MeSH terms: Odontogenic Tumors/pathology

Clear cell variant of calcifying epithelial odontogenic tumor without calcification: a rarity

Mutalik VS, Nichat P, Carnelio S, Solomon M, Radhakrishnan R

J Contemp Dent Pract, 2014 Jan 1;15(1):119-21.

PMID: 24939279

Calcifying epithelial odontogenic tumor (CEOT) is a rare, benign, locally aggressive odontogenic epithelial tumor that affects the jaws. Although there are numerous reports on the variants of CEOT, occurrence of clear cells with complete absence of calcification has been a rarity. Histochemical analysis of tumor cells revealed glycogen granules with PAS staining, with absence of CD 1a staining in clear cells, while the amyloid-like deposit associated with clear cells showed green birefringence with Congo red. We report an unusual variant of CEOT occurring in a 27 years old male patient.

Matched MeSH terms: Odontogenic Tumors/pathology*

Clinicopathological study of peripheral odontogenic fibromas (WHO-type) in Malaysians (1967-95)

Siar CH, Ng KH

Br J Oral Maxillofac Surg, 2000 Feb;38(1):19-22.

PMID: 10783442

Analysis of case records of 46 patients with peripheral odontogenic fibroma (1967-95) diagnosed in the Division of Stomatology, Institute for Medical Research, Kuala Lumpur, disclosed a relatively young age of onset (mean, 32.2 years; range 5 months-64 years; peak incidence second decade of life), a slight female preponderance (M:F ratio 1:1.3), no racial predilection, a slight bias towards location in the mandible (52%) and a wide histomorphological range. All cases were treated by simple excision. Follow-up records were generally not available, so we do not know what the recurrence rate is.

Matched MeSH terms: Odontogenic Tumors/pathology*

Aggressive (malignant?) epithelial odontogenic ghost cell tumour of the maxilla

Siar CH, Ng KH

J Laryngol Otol, 1994 Mar;108(3):269-71.

PMID: 8169519

A case is described of ameloblastoma of the mandible presenting with multiple recurrences and subsequent extension to the maxilla with resultant transformation into an aggressive (malignant?) epithelial odontogenic ghost cell tumour. The latter is a rare, biologically virulent entity that affects mainly males, exhibits a preference for the maxilla and is histologically characterized by atypical malignant odontogenic epithelium associated with areas of ghost cell formation and varying amounts of dentinoid.

Matched MeSH terms: Odontogenic Tumors/pathology*

Adenomatoid odontogenic tumour: a case study with radiographic differential diagnostic considerations

Siar CH, Ong ST, Ng KH

Singapore Dent J, 1996 Jul;21(1):19-22.

PMID: 10597178

Adenomatoid odontogenic tumours (AOT) are benign, hamartomatous odontogenic lesions that not uncommonly mimic a dentigerous cyst radiographically. Such a case as found involving an unerupted left maxillary canine in a 19-year-old Chinese female is described. The differential diagnosis of some common odontogenic cysts and neoplasms occurring in Malaysians, that may present in a dentigerous relationship to an unerupted tooth is discussed. A brief review of the radiographic literature on AOT is also included.

Matched MeSH terms: Odontogenic Tumors/pathology*

Calcifying odontogenic cysts in peninsular Malaysia. A report of 30 cases

Ng KH, Siar CH, Murugasu P

Ann Dent, 1986;45(2):19-22.

PMID: 3468872

Matched MeSH terms: Odontogenic Tumors/pathology*

Notch signaling and ghost cell fate in the calcifying cystic odontogenic tumor

Siar CH, Kawakami T, Buery RR, Nakano K, Tomida M, Tsujigiwa H, et al.

Eur J Med Res, 2011 Nov 10;16(11):501-6.

PMID: 22027644

Notch signaling is an evolutionarily conserved mechanism that enables adjacent cells to adopt different fates. Ghost cells (GCs) are anucleate cells with homogeneous pale eosinophilic cytoplasm and very pale to clear central areas (previous nucleus sites). Although GCs are present in a variety of odontogenic lesions notably the calcifying cystic odontogenic tumor (CCOT), their nature and process of formation remains elusive. The aim of this study was to investigate the role of Notch signaling in the cell fate specification of GCs in CCOT. Immunohistochemical staining for four Notch receptors (Notch1, Notch2, Notch3 and Notch4) and three ligands (Jagged1, Jagged2 and Delta1) was performed on archival tissues of five CCOT cases. Level of positivity was quantified as negative (0), mild (+), moderate (2+) and strong (3+). Results revealed that GCs demonstrated overexpression for Notch1 and Jagged1 suggesting that Notch1-Jagged1 signaling might serve as the main transduction mechanism in cell fate decision for GCs in CCOT. Protein localizations were largely membranous and/or cytoplasmic. Mineralized GCs also stained positive implicating that the calcification process might be associated with upregulation of these molecules. The other Notch receptors and ligands were weak to absent in GCs and tumoral epithelium. Stromal endothelium and fibroblasts were stained variably positive.

Matched MeSH terms: Odontogenic Tumors/pathology*

An immunohistochemical study of two cases of either peripheral odontogenic fibroma (WHO type) or peripheral ameloblastoma

Chong Huat Siar, Kok Han Ng

J Nihon Univ Sch Dent, 1996 Mar;38(1):52-6.

PMID: 8648412

Two cases of either peripheral odontogenic fibroma (POF) (WHO type) or peripheral ameloblastoma are reported. Their immunohistochemical characteristics were investigated in an attempt to clarify their histogenesis. The results showed that the epithelial component of this neoplasm tended to retain its distinct odontogenic character and expressed a keratin profile different from that of the overlying oral epithelium from which both cases most probably originated. The connective tissue element of these tumors was vimentin-positive and S-100 protein negative, confirming their mesodermal nature but precluding the possibility of ectomesenchymal derivation. No reactivity for desmin was noted.

Matched MeSH terms: Odontogenic Tumors/pathology*

Unusual granular cell odontogenic tumor. Report of two undescribed cases with features of granular cell ameloblastoma and plexiform granular cell odontogenic tumor

Siar CH, Ng KH

J Nihon Univ Sch Dent, 1993 Jun;35(2):134-8.

PMID: 7692017

Granular cell ameloblastoma (GCA) is a well recognized variant of follicular ameloblastoma with extensive granular cell change. In contrast, plexiform granular cell odontogenic tumor (PGCOT) is a rare and recently described lesion characterized histologically by a monophasic plexiform pattern of granular cells. In this paper, two cases of an unusual granular cell odontogenic tumor exhibiting combined features of these two entities are described along with their immunohistochemical characteristics. The granular cells of both the GCA and PGCOT areas showed similar patterns of expression for keratin and S-100, which differed from those of typical ameloblastoma. No reactivity for desmin or vimentin was noted. The histomorphologic and immunohistochemical features of these hybrid tumors suggest that the granular cells present have a common origin, most probably the odontogenic epithelium.

Matched MeSH terms: Odontogenic Tumors/pathology*

Cemento-ossifying fibroma with mandibular fracture. Case report in a young patient

Ong AH, Siar CH

Aust Dent J, 1998 Aug;43(4):229-33.

PMID: 9775467

The cemento-ossifying fibroma is classified as an osteogenic neoplasm of the jaws. It commonly presents as a progressively growing lesion that can attain an enormous size with resultant deformity if left untreated. A case of a large cemento-ossifying fibroma involving the left mandible is described in a 15 year old male patient. The clinical, radiographic and histological features as well as surgical findings are presented. The treatment of choice of this lesion is also emphasized. Two years after surgery, there was no evidence of recurrence and the transosseous wire used to immobilize the fracture was found to be completely buried in the jaw bone.

Matched MeSH terms: Odontogenic Tumors/pathology

Claudin expression and tight junction protein localization in the lining epithelium of the keratocystic odontogenic tumors, dentigerous cysts, and radicular cysts

Siar CH, Abbas SA

Oral Surg Oral Med Oral Pathol Oral Radiol, 2013 May;115(5):652-9.

PMID: 23601220 DOI: 10.1016/j.oooo.2013.02.013

The aim of this study was to evaluate the expression and localization of tight junction proteins (TJPs) or claudins in the keratocystic odontogenic tumor (KCOT) and to correlate with its biological behavior.

Matched MeSH terms: Odontogenic Tumors/pathology*

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