Calcifying Epithelial OdontogenicTumor(CEOT), also known as Pindborg tumor is a rare lesion comprising about 1% of all odontogenic tumors mostly rising in the posterior of the mandible. It generally occurs in patients between 30-60 years old. This paper describes a case of CEOT in a 17 year-old female affecting the right mandible. Histopathologic findings showed sheets of polygonal tumor cells and pools of amorphous, eosinophilic amyloids with calcifications. 1 year after resection of the tumor, no clinical and radiographic signs of recurrence were observed.

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.