Odontogenic Gingival Epithelial Hamartoma; with Reference to the Expression of Ameloblastin Gene by in situ Hybridization and Immunohistochemistry

Odontogenic gingival epithelial hamartoma (OGEH) is an extremely rare lesion characterized by an abnormal proliferation of odontogenic epithelium. This lesion is thought to arise from the rest of the dental lamina lying dormant in the gingival tissue after odontogenesis. Distinguishing OGEH from the granular cell variant of ameloblastoma and central odontogenic fibroma is important. To date, only eleven cases have been reported, and its pathogenesis remains unclear. We report here on a case of OGEH, where the epithelial strands in the lesion were conspicuously positive for the antisera of cytokeratin 19 and ameloblastin. Tumor cells intensely expressed ameloblastin mRNA by in situ hybridization. To the best of our knowledge, this is the first case of OGEH to which ameloblastin immunohistochemical stain and in situ hybridization were applied. Although our study is limited to a single case, the coexpression of cytokeratin 19 and ameloblastin might indicate the origin and specific cytodifferentiation of OGEH is quite different and unique, when contrasted to other odontogenic tumors.

Odontogenic Myxoma: Report of Two Cases

Odontogenic myxoma is one of rare tumors in oral and maxillofacial region and it is thought to be mesenchymal or ectomesenchymal origin. Its characteristics are benign and non-metastatic but it has the potential of local invasion and high recurrence rate. It originally occurs in atrium of heart and in central case, my xoma is located mainly in the maxilla and mandible. Most odontogenic myxoma develops in 2nd or 3rd decades of life and rarely occurs in child or older persons over fifty. The distribution of reported cases between the sexes is similar and the maxilla and mandible are equally affected or slightly higher in mandible. Clinically it is usually asymptomatic, however it can cause pain and paresthesia is complained in the advanced stages. Displacement and mobility of teeth have also been reported Odontogenic myxoma is not a frequent tumor, but in case of slow and painless growing tumor it must be considered as a differential diagnosis.

VEGF Expression and Microvessel Density in Oral Squamous Cell Carcinomas

Angiogenesis is an essential process in tumor growth and metastasis. VEGF has been considered a leading candidate inducing tumor angiogenesis. VEGF expression was significantly correlated with clinical stage, lymph node matastasis, and prognosis of cancers of various parts of body. However, little has been known about the correlation between VEGF expression and clinicopathologic parameters in oral squamous cell carcinoma. The aim of this study was to correlate VEGF expression with the clinicopathological parameters and microvessel density. Forty six oral squamous cell carcinomas were analyzed using immunohistochemical method with primary antibodies to VEGF and CD31. VEGF expression was detected in 33 (71.7%) of the 46 cases. The microvessel density was significantly correlated with VEGF expression (P=0.002). There was no correlation between microvessel density and tumour size, clinical stage, and lymph node metastasis, respectively. VEGF expression did not correlate with the histological grade of tumour differentiation, tumour size, and clinical stages. The VEGF-positive rate seemed to be higher in patients with cervical lymph nodal metastasis than in those without it, but it was not statistically significant. In conclusion, the overexpression of VEGF in the oral squamous cell carcinoma seemed to be associated with a more aggressive course of the disease. Further study is necessary to define the role of VEGF in oral squamous cell carcinoma.

Expression of Matrix Metalloproteinase-2 and -9 in Oral Squamous Cell Carcinomas in Relation to the Histologic Invasiveness and Cellular Differentiation

A poor prognosis of oral squamous cell carcinoma (SCC) is partly due to the invasiveness and metastasis of the tumor. A key element in tumor invasion and metastasis in the degradation of extracellular matrix is matrix metalloproteinases (MMPs). This study was performed to determine the expression of MMP-2 and MMP-9 of oral SCCs with regard to the histologic invasiveness and differentiation in 5 normal oral mucosa and 36 oral SCCs. The histologic invasiveness of oral SCCs were classified into 4 grades. The differentiation of oral SCCs was divided into 3 grades. The streptavidin-biotin immunohistochemical staining, using MMP-2 and MMP-9 monoclonal antibodies, was performed to determine the expression of MMP-2 and MMP-9. The expression of MMP-2 was positive in 6 of 17 oral SCCs with weak invasiveness and was positive in 7 of 19 oral SCCs with strong invasiveness. The MMP-2 expression did not increase significantly with respect to the invasiveness of oral SCCs (P>0.05). The expression of MMP-9 was strongly positive in 6 out of 17 SCCs with weak invasiveness and was strongly positive in 14 of 19 SCCs with strong invasiveness. The MMP-9 expression increased significantly with respect to the invasiveness of oral SCCs; the stronger the expression, the stronger the invasiveness (P<0.05). The expression of MMP-9 was in 57.9% of well differentiated SCCs, 57.1% of moderately differentiated ones, and 33.3% of poorly differentiated SCCs. The expression of MMP-2 and MMP-9 did not increase significantly with respect to the histologic differentiation. We conclude that with respect to the invasiveness, the MMP-9 expression increases significantly in oral SCCs but the MMP-2 expression does not; and that with respect to the histologic differentiation, their expressions do not increase significantly. These results suggeste that MMP-9 can be used as a tool to evaluate the invasiveness of oral SCCs.

Evaluation of Prognostic Significance of AgNORs and PCNA during 9,10-dimethyl-1,2-benzantracene(DMBA)-induced Hamster Buccal Pouch Carcinogenesis

The purpose of this study is to evaluate the prognostic significance of argyrophilic nucleoalr organizer regions (AgNORs) and proliferating cell nuclear antigen (PCNA) by using DMBA hamster buccal pouch carcinogenesis which provides a good experimental model in reproducing steps from precancerous lesions to invasive squamous cell carcinomas. The buccal pouches of 50 Syrian hamsters were applied with 0.5% DMBA in mineral oil three times a week to reproduce various lesions from precancerous ones such as hyperkeratosis or epithelial dysplasia to invasive squamous cell carcinomas. Their sections were stained with H & E, and silver colloid, and processed immunohistochemically by being applied with monoclonal antibody to PCNA. The histopathologic examainations were done and the counts of AgNORs were evaluated. The PCNA labelling indices on each lesions were evaluated. The correlation between histopathological grades and counts of AgNORs or PCNA labelling indices were evaluated. The number of AgNORs was 2.22+/-0.22 in control group, 3.46+/-0.72 in carcinoma in situ (CIS), 3.78+/-0.63 in squamous cell carcinoma (SCC), respectively. AgNORs significantly increased in severe epithelial dysplasia, CIS, and SCC compared with normal tissue (P<0.05). The PCNA Labeling Index (LI) was 39.47+/-6.68% in control group, 79.61+/-4.14% in CIS, and 85.43+/-6.25% in SCC, respectively. PCNA LI also significantly increased in epithelial dysplasia, CIS, and SCC compared with normal tissue (P<0.05). The number of AgNORs, AgNOR area, and PCNA LI slightly increased in the advancing front than in the center of SCC, but, it was not statistically significant. It appeared that there were a good correlation between the number of AgNORs and PCNA LI (Pierson correlation coefficient : 0.649, P<0.001). These results suggested that the number of AgNORs and the PCNA LI could be useful markers for evaluating the risk of malignant transformation and prognosis of SCC. It was thought that the clinical usefulness of these markers should be verified by using human tissue specimens.

Fine needle aspiration cytology of malignant ameloblastoma metastasized to the lung-a case report- / 대한세포병리학회지

No abstract available.

Development and Growth of Tongue in Korean Fetuses

We examined sixty-three human embryos ranged from three weeks to eight weeks of fertilization age and 117 human fetuses from eleven weeks to fourty weeks of gestational age. Anatomical structure of developing tongue could be classified into eight developmental stages. The first is the sgage of mesial swelling of tongue primordium in the fertilization age of 28~40 days (Streeter stage 13~16), the second is the stage of lateral swelling of tongue primordium in the fertilization age of 41~46 days (Streeter stage 17~18), the third is the sgage of vertical positioning of tongue in the fertilization age of 47~53 days (Streeter stage 19~21), the fourth is the transitional stage of tongue from vertical position to horizontal position in the fertilization age of 54~56 days (Streeter stage 22~23), the fifth is the stage horizontal positioning of tongue in the gestational age of 11 weeks, the sixth is the stage of protrusion of tongue in the gestational age of 12 weeks, the seventh is the stage of maturation of tongue muscle in the gestational age of 7-10 months. The development of tongue papilla characteristically progresses into three stages. The first stage is the epithelial ingrowth for the crypt formation, the second stage is the anatomical formation of vallate, fungiform and filiform papillae, and the third stage is the differentiation of taste buds in the vallate and fungiform papillae or the formation of thick spike-like keratinization at the tip of filiform papilla. We observed that the tongue primordium mainly derived from occipital myotome developed more repidly than other oro-facial structures, so it transitionally occuied the spaces of the pharynx and the posterior nasal cavity, and directly affected the formation of palate and the growth of maxilla and mandible. Whereas the tongue papilla development showed continuous developmental sequences during the fetal period.

Supernumerary Tooth Germs in the Incistive Canal of Five Fetal Maxillas

Five fetal maxillas were obtained from the autopsy file of fetal postmortem examination, and were examined by serial micro-sections of frontal plane and horizontal plane. Especially the area around the incisive canal of the maxilla was carefully observed. The results are as follows. 1) In 5 fetal maxillas extra-dental laminas and supernumerary tooth germs which are severely malformed in shape are found in the dilated incisive canal, where prominent vessels and nerves are distributed. 2) The supernumerary tooth germs disclose almost normal histo-differentiation of odontoblast and ameloblast, and there shows relatively abundant perifollicular fibrosis in the place of perifollicular bone. 3) It is observed that the over-growth of the extradental lamina from the dental ridge of deciduous central incisor frequently tends to direct toward the incisive canal that includes prominent vessels and nerves.

Weekly Development and Growth of Tooth Germ in Korean Fetuses

In order to elucidate the developmental stages of human tooth germ during prenatal period, we examined 254 normal fetuses ranging in gestational age from six weeks to fourty weeks old histologically. Lim's developmental pattern of prenatal tooth germ was divided into three groups, the first group consisting of five grades (I, II, III, IV, V) was for the development of enamel epithelium the second group of three grades was for the deposition of dentin matrix and enamel matrix, and the third group of three grades (A, B, C) was for the growth of perifollicular bone. Some developmental progress between enamel epithelium and dental papilla could be identified by observation of the sequential development of deciduous and permanent tooth germs histologically. The following results were made. 1) The prenatal development of tooth germ showed similar weekly stages in both the maxilla and the mandible. The initial deposition of dentin matrix and enamel matrix (III-1 stage) started at 12-14 weeks of gestational age in the deciduous incisor and canine, and at 16-20 weeks of gestational age in the deciduous molars. And the initial deposition of dentin matrix and enamel matrix in the permanent first molar was at 20-22 weeks of gestational age, and that of the permanent incisor was at 34-36 weeks, and that of the permanent canine was 36-38 weeks, and of the permanent premolar was at 38-40 weeks. 2) The S-shaped curvature was characteristically found where the reciprocal induction of odontoblast and amelobast occurred actively in the developing tooth germ. Primarily pre-ameloblasts which abutted on the dental papilla differentiate the condensed mesenchymal cells into odontoblasts, and secondarily matured odontoblasts which bulged into enamel epithelium produced dentin matrix and differentiated the shrunken pre-ameloblasts into ameloblasts. 3) The mandible grew more rapidly than the maxilla during the early prenatal period. The trabecular bone from both jaws proliferated initially into labial side of developing tooth follicle and gradually circumscribed the tooth follicle lingually and mesio-distally, to form perifollicular bone resultantly.

Melanotic neuroectodermal tumor of infancy

A case of melanotic neuroectodermal tumor of infancy was presented. This tumor occurred in the right maxillary alveolar ridge of 3-month-old female infant, showing bluish enlargement of alveolar mucosa with the displacement of central deciduous incisor. We described the gross, microscopic, and ultrastructural findings of this tumor. This case appears to be the first case of MNTI, reported in a Korean.