Clear cell odontogenic carcinoma (CCOC), a very rare neoplasm located mostly in the mandible, has been regarded as a benign tumor. However, due to the accumulation of case reports, CCOC has been reclassified as a malignant entity by the World Health Organization. Patients with CCOC present with regional swelling and periodontal indications with variable pain, often remaining misdiagnosed for a long period. CCOC has slow growth but aggressive behavior, requiring radical resection. Histologic analysis revealed the monophasic, biphasic, and ameloblastic types of CCOC with clear cells and a mixed combination of polygonal and palisading cells. At the molecular level, CCOC shows the expression of cytokeratin and epithelial membrane antigen, along with markers that assign CCOC to the sarcoma family. At the genetic level, Ewing sarcoma breakpoint region 1-activating transcription factor 1 fusion is regarded as the key feature for identification. Nevertheless, the scarcity of cases and dependence on histological data delay the development of an efficient therapy. Regarding the high recurrence rate and the potential of distant metastasis, further characterization of CCOC is necessary for an early and accurate diagnosis.

Squamous odontogenic tumor (SOT) is a relatively rare, benign, small (rarely > 1.5 cm in diameter), but locally infiltrative and occasionally aggressive odontogenic epithelial lesion that appears to have harmatomous and neoplastic characteristics [1]. SOT is often asymptomatic, although it can present with mildly painful gingival swelling or tooth mobility. Radiographically, SOT is usually visualized as an irregularly or triangularly shaped unilocular radiolucency associated with the lateral roots of teeth. We report a case of the squamous odontogenic tumor occurring in a 60-year-old female in the right posterior maxilla with unusual radiographic and clinical appearances.

A nineteen years old male patient showed a cystic lesion in left maxillary canine to premolar area (#23-#25). This lesion was asymptomatic, and found during his routine radiological check in local clinic. In the radiological observation the cystic lesion showed round radiolucent image containing many calcified bodies which were usually small but irregular in shape, expanding tumorously and resulted in the displacement of canine and second premolar in the absence of first premolar. The lesion was surgically enucleated, and a cystic fibrous tissue containing abnormal teeth was removed and examined pathologically. With the histological observation of tumorous odontogenic epithelium including many ghost cells, which were closely associated with abortive teeth, the lesion was finally diagnosed as CCOT associated with complex odontoma. The ghost cells of CCOT was strongly positive for β-catenin, GADD45, and LC3, and slightly positive for MMP-9, while they were rarely positive for BCL2, Wnt1, HSP-70, and p38. Therefore, it was presumed that the ghost cells of CCOT might undergo dormant cell state through altered cytodifferentiation stimulated by severe growth arrest, DNA damage signaling, and abundant autophage formation.

Calcifying cystic odontogenic tumor (CCOT), also known as calcifying odontogenic cyst or Gorin cyst is a rare developmental lesion which arises from odontogenic epithelium. It has been classified as a benign odontogenic neoplasm related to odontogenic apparatus by the World Health Organization. CCOT may be associated with other odontogenic tumors, most frequently odontoma, a finding that is a rare event in other types of odontogenic cysts or tumors. This report describes a case of hybrid odontogenic tumor composed of CCOT and ameloblastic fibroma-odontoma of the impacted right maxillary canine region that occurred in a 14-year-old female.

Squamous odontogenic tumor (SOT) is a rare benign neoplasm first described by Pullon et al. in 1975. Clinically and histologically, it is confused with ameloblastoma, carcinoma and local periodontoal disease. We report a case of SOT occuring in a 16-year-old female in the right mandibular angle location associated with an impacted molar

The central granular cell odontogenic tumor is a rare benign odontogenic neoplasm of uncertain hisotogenesis characterized by varying amounts of eosinophilic granular cells and apparently inactive odontogenic epithelium with variable presence of calcified tissue. We present a case of central granular cell odontogenic tumor involving the maxilla of 35-year-old man with immunohistochemical characterization of granular cells. In microscopic view, the granular cells densely packed in sheets and lobules with abundant eosinophilic, granular cytoplasm and eccentric round-to-ovoid nuclei revealed immunoreactivity for vimentin, α1-antitrysin and CD68, and NSE but not for cytokeratin and S-100 protein while the interspersed odontogenic epithelial cells were positive for cytokeratin only. Granular cells also revealed strong PAS staining. Numerous concentric structured round to ovoid calcified aggregates were also noted. The lesion was treated with excision without recurrence for 8 years. Our immuohistochemical staining findings also suggest that the granular cells of central granular cell odontogenic tumor are mesenchymal in origin with possible histiocytic differentiation

Central granular cell odontogenic tumor (CGCOT) is a rare benign odontogenic neoplasm, with approximately 30 cases having been reported. The pathogenesis of CGCOT as well as the designation of this lesion is controversial because of unknown histogenesis of the granular cell. We present an additional case of CGCOT involving the mandible of a 50-year-old Korean man who complained of asymptomatic swelling of the right buccal gingiva. Current lesion is microscopically characterized by densely packed polyhedral granular cells surrounding interspersed islands or strands of odontogenic epithelium. Immunohistochemically, granular cells were positive for Vimentin and CD68, and negative for cytokeratin and S-100. These features support a mesenchymal origin for the granular cells as other results previously reported.

was first described by Pindborg in 1955. they occur as intraosseous(94%) and extraosseous variants. Although the prognosis of CEOT was regarded as ameloblastoma in the past, contemporary accumulating data suggest that CEOT have better prognosis than ameloblastoma. But decisive evidences are lacked. Although CEOT is a rare odontogenic tumor, the histopathologic features have so much diversity. Especially interesting aspects are the being of amyloid and Langerhans' cells. Author classify 6 cases of CEOT to scanty, small, and lage as produced amount of amyloid and then perform immunohistochemical study about pancytokertin, cytokeratin8/18, vimentin, CD1a, and VEGF(vascular endothelial growth factor) for verifying the differentiation state of tumor cells and the comparative infiltrative potential with ameloblastoma. Author obtain several conclusion and presumptive facts through this study and previous researchs. Tumor cells of CEOT exhibited different differentiating features as amount of amyloid, presumably tumor cells of CEOT with scanty amount of amyloid represent enamel epithelium-like cells of presecretory stage in amelogenesis, tumor cells of CEOT with small amount of amyloid represent ameloblast-like cells of secretory stage in amelogenesis, and tumor cells of CEOT with large amount of amyloid represent reduced enamel epithelium-like cells after enamel formation. Epithelial-Mesenchymal transition phenomenon developed in tumor cells of CEOT with small amount of amyloid. Inflammatory reaction was not related with being Langerhansʼ cells. Author tentatively concluded that CEOT with Langerhans cells exhibited a tendency of non-calcification, scanty amyloid formation and frequently occurring at the maxillary anterior region through the previous studies and this study. Infiltrative growth potential of CEOT was lower than ameloblastoma regarding only VEGF expression.

Combined epithelial odontogenic tumors are very rare and represent hybrid lesion comprising adenomatoid odontogenic tumor intermixed with calcifying epithelial odontogenic tumor. The authors present 3 cases of combined epithelial odontogenic tumor which contained diagnostic areas for both adenomatoid odontogenic tumor and calcifying epithelial odontogenic tumor. Their behaviour and histogenesis were discussed.

In order to perform the protein analysis using the paraffin sections previous fixed with formalin, we applied the ImmunoMemBlot (IMB) method1) to detect the epitopes of target proteins with specific antibodies. In this study the protein extracts were obtained from the paraffin sections of each representative case of ameloblastoma, adenomatoid odontogenic tumor (AOT), and normal gingiva, and more a protein extract from fresh tissue of ameloblastoma was also compared to evaluate the IMB results used with 24 different antibodies. First of all, in the comparison between the paraffin section extract and fresh tissue extract of ameloblastoma, the latter consistently showed more positive IMB reaction than the former. Meanwhile, the paraffin section extract of ameloblastoma was more comparable with that of normal gingival, disclosing that most of proliferating genes, oncogenes, and apoptosis related genes, i.e., PCNA, CDK4, c-erbB2, CEA, p53, Bax, Bad, FLIP, FAS, Bcl-2, p21, N-ras, MMP-2, MMP-9, caspase-3, -8, -9, were highly expressed in ameloblastoma, but EGFR, HGF, and VEGF were similarly expressed both in the ameloblastoma and in normal human gingiva. On the other hand, the comparison between ameloblastoma and AOT both in the immunohistochemistry and IMB using their paraffin section extracts clearly demonstrated that the ameloblastoma showed more expression of proliferating genes and oncogenes while the AOT showed more expression of apoptosis related genes, i.e., Bax, Bad, FLIP, and caspase-9. Taken together, these data suggest that the IMB can be used for the primary screening of quantitative protein analysis using the paraffin section extract, and that the IMB results could be evaluated in conjunction with the immunohistochemical observation.

Ameloblastoma and adenomatoid odontogenic tumor showed quite different tumorigenesis and prognosis , Besides theil‘ growth potential and histological features , there must be an essential diffcJ'cncc in gene expJ'ession profile between ameloblatoma and adenomatoid odontogenic tumor , The gene expression profiles we1'e compared by im munohi stochemi stry and immunoblot methods using different monoclonal and monospecific antibodies against on cogenes, growth factors, signaling molecules‘ matrix proteins, enzymes, Based on the immunohi stochemical find ings previously J'epo1'ted in the literature we found some di stinguishing feature of gene expressions 1'0 1' the tu mOl'igenesis between ameloblastoma and adenomatoid odontogenic tumors , The hi s togeneti c and mol eculal' mechani sms of both tumors wiII be discussed

The adenomatoid odontogenic tumor(AOT) is a benign tumor of odontogenic epithelium characterized by slow but progressive growth and rare recurrence. Tumor growth may cause displacement of teeth rather than root resorption. The AOT appears in 3 clinicotopographic variants such as follicular, extrafollicular, and peripheral. The follicular AOT mimics a dentigerous or follicular cyst and the extrafollicular cyst does a residual cyst, globulo-maxillary cyst and lateral periodontal cyst. Although over 750 cases of AOT were reported in the literature, clinicopathologic parameters of AOT in Koreans has not been investigated. 22 cases of AOT were retrieved from the files of the department of Oral Pathology, Seoul National University Dental Hospital and their clinicopathologic findings were reviewed. The central type accounts for 95%, 72% of which are follicular. The follicular and extrafollicular varients together are more commonly found in the maxilla than in the mandible with a ratio of 4.5:1. Age distribution showed that 59% of AOTs were diagnosed in the second decade of life, and mean age was 18.5 years. The female to male ratio was 3.4:1. All variants of AOT showed identical histologic features.

Odontogenic ghost cell tumor (OGCT) is considered as a neoplastic counterpart of the calcifying odontogenic cyst (COC). β-catenin mutations have been described in COC suggesting a critical role in its histogenesis. In this study, we report a patient with OGCT contains a missense mutation on codon 3 (ACT -> TCT). Immunohistochemistry showed nuclear, cytoplasmic, and membranous accumulation of β-catenin in the tumor cells. TUNEL assay showed positive signals in nucleated cells adjacent to the ghost cells. Our data suggest that β-catenin plays an important role in the tumorigenesis of OGCT. OGCT may developed by improper differentiation process coordinated by WNT signaling pathway. Further studies are needed to determine a genotypic/phenotypic characteristics of ghost cell containing odontogenic lesions.

In odontogenic osteolytic lesions, the mechanism involved in inflammation 때d osteolysis is still under debate. We investigated the role 。OL-l ~ -1 ß, -4, -6, -8, TNF- a in the expansion of the odontogenic cysts, by using 50 cases of excised odontogenic cysts. The degrees of inflammation were graded into 2 groups and immunohistochernical stainings were performed, The cytoplasrnic reaction in squamous epithelial cells, stromal cells and infIitrating inflammatory cells was examined. The relationship between the expressions of IL-1 q -1 ß, -4, -6, -8, π-JF- aand the degree of inflammation and the correlation among them were analyzed. 까1e 비Stilαγtic expressions of IL-l ~ IL-l ß and TNF-awere 66.6%, 66.6% and 4O.00Al respeαively and the epithelial exp~않sions of IL-4, -6, -8 were 32.00Al, 38.00Al and 24.00Al respeαively. IL-4, -6 and 용 were positively stained in plasma cells in 38.00Al, endothelial cells in 40.00/0 and neutrophils in 24. 00Al respectively. The expresssion rate of IL-4 in plasma cells and IL-8 in epithelium and neutrophils were inα얹sed in ca않s with marked inflammation. 까1e exp!1않sion rate of IL-1 ßin 피해ocytes and IL-4 in plasma cells were positively correlated with the expæssion of TNF-1 ain histiocytes. π1e expression rate of anti-inflammatory cytokine IL-4 in the epithelium were correlated with the expression of IL-6 in the epithelium and endothelial cells. A1though statistically insi.맑표ìcant， the expression rate of IL-6 were decreased in cases with marked inflammation and nega디vely correlated with IL-8, the proinflammatory cytokine, and the expressions of IL-4 and IL-6 in the epithelium can be considered as inhibiting the inflammatory reaction. These results suggest that the expressions of IL-4 and IL-6 suppress and IL-8 stimulates the inflammatory reaction in Odontogenic Cysts.

World Health Organization(WHO) revised the classification of neoplasms and other tumours related to odontogenic apparatus in 1992. The aim of this study was to classify the odontogenic tumors of Korean according to the WHO Histologic classification. A total of 271 cases were reviewed for the study which were diagnosed as odontogenic tumors at the department of Oral Pathology, Yonsei University College of Dentistry for the period from Jan. 1997 to March 2003. Clinical and pathology reports were reviewed & radiographic feature were examined. The following results were obtained : 1. Among 271 cases, 269 cases(99.3%) were diagnosed as benign odontogenic tumors, and the remaining 2 cases(0.7%) were malignant tumors, which were diagnosed as odontogenic ghost cell carcinoma and squamous cell carcinoma ex odontogenic cyst. 2. Four cases were not able to classify into the WHO classification. All of them were belonged to mixed odontogenic tumors; two cases of adenomatoid odontogenic tumor with calcifying epithelial odontogenic tumor, one case of adenomatoid odontogenic tumor with odontoma, odotogenic cyst and one case of ameloblastoma with immature odontoma. 3. The most frequent odontogenic tumour was odontoma(45.2%), followed by ameloblastoma (29.2%), odontogenic fibroma(9.2%) 4. One case of atypical amelobalstoma and one case of calcifying odontogenic cyst with ameloblastic fibroma were not able to subclassify histologically. 5. Male to female ratio of odontogenic tumors was 1.2:!. Odontogenic tumors mainly occured in the first and second decade, occurred twice as much as in the mandible than in the maxilla 6. The odontogenic tumors was discovered by routine oral x-ray examination, whereas the chief complaint of ameloblastoma were swelling, pain. 7. Ameloblastoma, adenomatoid odontogenic tumor, calcifying odontogenic cyst and odontoma were related to the impacted teeth and tooth displacement. The root resorption was frequently observed in ameloblastoma and calcifying odontogenic cyst.

A case of odontogenic ghost cell tumor (OGCT) with clear cell components occurred in the mandible of a 63-yearold man. The tumor revealed ameloblastomatous type epithelial components together with clusters of ghost cells and dentinoid juxtaposed to the odontogenic epithelium. In addition, some areas of the tumor tissue showed sheets and islands of clear, glycogen-rich epithelial cells, separated by a thin fibrous connective tissue stroma. Both ameloblastic and clear cells showed positive immunoreactivities for cytokeratin 19 and AE1/3. It is not known whether this tumor represents a clear cell differentiation of a preexisting OGCT or a separate and distinct neoplasm derived de novo from odontogenic epithelium. This tumor was preferred the term clear cell odontogenic ghost cell tumor, which captures the clear cell components, one of the tumors most prominent distinguishing features