MyMedR

Podoplanin, E-cadherin, β-catenin, and CD44v6 in recurrent ameloblastoma: their distribution patterns and relevance

Siar CH, Ishak I, Ng KH

J Oral Pathol Med, 2015 Jan;44(1):51-8.

Ameloblastoma is a benign but locally infiltrative odontogenic epithelial neoplasm with a high risk for recurrence. Podoplanin, a lymphatic endothelium marker, putatively promotes collective cell migration and invasiveness in this neoplasm. However, its role in the recurrent ameloblastoma (RA) remains unclear. As morphological, signaling, and genetic differences may exist between primary and recurrent tumors, clarification of their distribution patterns is of relevance.

Matched MeSH terms: Mandibular Neoplasms/pathology

Notch4 overexpression in ameloblastoma correlates with the solid/multicystic phenotype

Siar CH, Nagatsuka H, Chuah KS, Rivera RS, Nakano K, Ng KH, et al.

Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 2010 Aug;110(2):224-33.

PMID: 20659700 DOI: 10.1016/j.tripleo.2010.03.009

Notch signaling has been implicated in cell fate decisions during odontogenesis and tumorigenesis of some odontogenic neoplasms; however, its role in solid/multicystic (SA), unicystic (UA), and recurrent (RA) ameloblastoma remains unclear. The aim of this study was to determine Notch receptor and ligand expressions in these subtypes and to speculate on their significance.

Matched MeSH terms: Mandibular Neoplasms/pathology

Differential expression of Notch receptors and their ligands in desmoplastic ameloblastoma

Siar CH, Nakano K, Han PP, Nagatsuka H, Ng KH, Kawakami T

J Oral Pathol Med, 2010 Aug 1;39(7):552-8.

PMID: 20337864 DOI: 10.1111/j.1600-0714.2009.00871.x

In mammals, the Notch gene family encodes four receptors (Notch1-4), and all of them are important for cell fate decisions. Notch signaling pathway plays an essential role in tooth development. The ameloblastoma, a benign odontogenic epithelial neoplasm, histologically recapitulates the enamel organ at bell stage. Notch has been detected in the plexiform and follicular ameloblastoma. Its activity in the desmoplastic ameloblastoma is unknown.

Matched MeSH terms: Mandibular Neoplasms/pathology

Squamous odontogenic tumor of the mandible: a case report demonstrating immunoexpression of Notch1, 3, 4, Jagged1 and Delta1

Siar CH, Nakano K, Ng KH, Tomida M, Nagatsuka H, Kawakami T

Eur J Med Res, 2010 Apr 08;15(4):180-4.

PMID: 20554499

BACKGROUND: Squamous odontogenic tumor (SOT) is a rare benign odontogenic epithelial neoplasm. A slow-growing painless expansive swelling is the common presenting symptom. Histopathologically, SOT can be easily misdiagnosed as an acanthomatous ameloblastoma. Although Notch receptors and ligands have been shown to play a role in cell fate decisions in ameloblastomas, the role of these cell signaling molecules in SOT is unknown.

CASE REPORT: This paper describes a case of SOT affecting the anterior mandible of a 10-year-old Indian female. The patient was treated by local surgical excision and there has been no follow-up clinical record of recurrence 5 years after primary treatment. Histo?pathological examination revealed a solid, locally-infiltrative neoplasm composed of bland-looking squamatoid islands scattered in a mature fibrous connective tissue stroma and the diagnosis was SOT. Immunohistochemical evaluation showed positive reactivity of varying intensity in the neoplastic epithelial cells for Notch1, Notch3, Notch4, and their ligands Jagged1 and Delta1. Expression patterns showed considerable overlap. No immunoreactivity was detected for Notch2 and Jagged2.

CONCLUSIONS: Present findings suggest that Notch receptors and their ligands play differential roles in the cytodifferentiation of SOT.

Matched MeSH terms: Mandibular Neoplasms/pathology

A clinicopathologic study of odontomas: Malaysian findings

Ng KH, Siar CH

J Nihon Univ Sch Dent, 1997 Dec;39(4):171-5.

PMID: 9476429

This report reviews the clinicopathologic characteristics of 104 cases of odontomas diagnosed in the Division of Stomatology, Institute for Medical Research, Kuala Lumpur, over a 29-year period (1967-1995). The results showed no real predilection in terms of sex (M:F ratio, 1:1), race (45.2% Malays, 40.4% Chinese, 10.6% Indians and 3.8% other races) or site (maxilla:mandible ratio, 1: 1.04) distribution. The mean age at presentation was 24.8 years and the age range was 3-74 years. There were 102 intraosseous and 2 extraosseous odontomas. Swelling was the most common presenting complaint. The majority of cases (81.9%) were clinically diagnosed as odontomas. The treatment of choice was surgical enucleation. Compound (43.3%) and complex (35.5%) odontomas were the two most common histological types encountered. The present findings correlate favorably with reported studies from other geographic areas.

Matched MeSH terms: Mandibular Neoplasms/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: Mandibular Neoplasms/pathology*

RANK, RANKL, and OPG in recurrent solid/multicystic ameloblastoma: their distribution patterns and biologic significance

Siar CH, Tsujigiwa H, Ishak I, Hussin NM, Nagatsuka H, Ng KH

Oral Surg Oral Med Oral Pathol Oral Radiol, 2015 Jan;119(1):83-91.

PMID: 25446507 DOI: 10.1016/j.oooo.2014.09.017

To determine the distribution patterns of bone resorption regulators, receptor activator of nuclear factor κ-B (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG) in recurrent ameloblastoma (RAs) and to clarify their impact on the biologic behavior of these neoplasms.

Matched MeSH terms: Mandibular Neoplasms/pathology*

Ameloblastoma of the jaws: a retrospective analysis of 340 cases in a Malaysian population

Siar CH, Lau SH, Ng KH

J Oral Maxillofac Surg, 2012 Mar;70(3):608-15.

PMID: 21723654 DOI: 10.1016/j.joms.2011.02.039

Ameloblastoma of the human jaw is an uncommon but clinically significant odontogenic epithelial neoplasm. The aim was to analyze the clinicopathologic characteristics of ameloblastoma in a Malaysian population.

Matched MeSH terms: Mandibular Neoplasms/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: Mandibular Neoplasms/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: Mandibular Neoplasms/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: Mandibular Neoplasms/pathology

Fulltext Ameloblastomas--a clinicopathologic study of 133 cases in peninsular Malaysia

Ramanathan K, Chelvanayagam PI, Ng KH, Ramanathan J

Med J Malaysia, 1982 Mar;37(1):18-24.

PMID: 7121342

Ameloblastomas formed 1.1 percent of all oral pathology cases reported. The race, sex and age group distribution of 133 cases are shown. The peak age incidence (70.6 percent) was between 11-40 years. The mandible was involved 9 times more commonly than the maxilla. The anatomical sites of distribution, clinical and radiological features, histological variants and their correlation are discussed. Twenty two patients (15 percent) had ameloblastomas associated with a dentigerous cyst and/or unerupted teeth. Ameloblastomas with the above clinical features represented a much less aggressive form of neoplasm. The authors could not correlate histological variants of ameloblastoma with recurrence rates. The various treatment methods and the respective recurrence rates are outlined. Radiotherapy and marsupialization as treatment of ameloblastoma are not recommended. The indications for enucleation curettage, resection en bloc, segmental resection and hemimandibulectomy
are emphasized. Ameloblastomas involving the maxilla should be treated by complete removal en bloc with a margin of normal tissue. Since ameloblastoma has the capacity to recur after several years of apparent cure patients who have been treated for ameloblastoma must be followed up periodically during their life time. So far no case of ameloblastoma in this study has shown evidence
ofmetastasis.

Matched MeSH terms: Mandibular Neoplasms/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: Mandibular Neoplasms/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: Mandibular Neoplasms/pathology

Desmoplastic variant of ameloblastoma in Malaysians

Ng KH, Siar CH

Br J Oral Maxillofac Surg, 1993 Oct;31(5):299-303.

PMID: 8218083

Seventeen cases are reported of desmoplastic variant of ameloblastoma of the jaws observed during the years 1967-1991. There were 12 females and 5 males, and these consisted of 7 Chinese, 6 Malays, 2 Indians, 1 Sikh and 1 Kadazan. Their ages at diagnosis ranged from 21-60 years with a mean of 36.6 years. There were 10 mandibular and 7 maxillary tumours. Of these, 14 cases involved the anterior segment with extension to the premolar region in 5 cases. 60% of cases were radiologically suggestive of fibro-osseous lesions. The main mode of treatment was resection and 1 case presented with recurrence. The findings of this study were compared with those of previous reports.

Matched MeSH terms: Mandibular Neoplasms/pathology*

Unicystic ameloblastoma: a late recurrence with pseudo-glandular features. A case report

Khoo SP, High AS, Awang MN

Singapore Dent J, 1995 Jul;20(1):21-3.

PMID: 9582685

A case of unicystic ameloblastoma which recurred after 15 years showing unusual histological features is reported. The prominent pseudo-glandular features present are described. This case highlights the importance of extensive histological examination for more characteristic features of ameloblastoma to reach a correct diagnosis.

Matched MeSH terms: Mandibular Neoplasms/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: Mandibular Neoplasms/pathology*

Peripheral ameloblastoma with clear cell differentiation

Ng KH, Siar CH

Oral Surg. Oral Med. Oral Pathol., 1990 Aug;70(2):210-3.

PMID: 2290651

This report details a case of mandibular peripheral ameloblastoma having a clear cell component. The latter consisted of ovoid cells with vacuolated or clear cytoplasm and vesicular or pyknotic nuclei that may be disposed as discrete clusters or show direct transition from typical acanthomatous areas. Comparison of this lesion with other odontogenic and nonodontogenic tumors that contain clear cells is discussed in the context of the differential diagnosis.

Matched MeSH terms: Mandibular Neoplasms/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: Mandibular Neoplasms/pathology*

Burkitt's lymphoma in the mandible--a case report

Boon LC, Nik-Hussien NN

Br J Oral Maxillofac Surg, 1987 Oct;25(5):410-4.

PMID: 3478086

Burkitt's lymphoma is a tumour that most often affects the jaws, especially in endemic areas of Africa. In non-endemic areas, the jaws are affected in about 15-18% of cases. A case is presented which demonstrates the significance of jaw lesions in the disease. The history and pathogenesis of the disease also are discussed.

Matched MeSH terms: Mandibular Neoplasms/pathology

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