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The calcifying epithelial odontogenic tumor, also known as a Pindborg tumor or CEOT, is an odontogenic tumor first recognized by the Danish pathologist Jens Jørgen Pindborg in 1955. It was previously described as an ''adenoid adamantoblastoma'', ''unusual ameloblastoma'' and a ''cystic odontoma''.〔 Like other odontogenic neoplasms, it is thought to arise from the epithelial element of the enamel origin.〔 It is a typically benign and slow growing, but invasive neoplasm.〔 Intraosseous tumors (tumors within the bone) are more likely (94%) versus extraosseus tumors (6%).〔 It is more common in the posterior mandible of adults,〔 typically in the 4th to 5th decades. There may be a painless swelling, and it is often concurrent with an impacted tooth. On radiographs, it appears as a radiolucency (dark area) and is known for sometimes having small radiopacities (white areas) within it. In those instances, it is described as having a "driven-snow" appearance. Microscopically, there are deposits of amyloid-like material. The underlying nature of the amyloid-material is still unresolved.〔 Clinically it has two types, the central and the peripheral. The central type of the CEOT occurs in individuals ranging in age from 20–60 years. Two-thirds of the lesions are in jaws, more commonly in the molar area with a tendency to occur in the pre-molar areas.〔 It appears clinically to be a slowly enlarging painless mass. In the maxilla it can cause proptosis, epistaxis and nasal air way obstruction. The peripheral type is commonly found in the anterior region of the maxilla and occurs as a soft tissue swelling. Histopathology will reveal prominent intercellular bridges and nuclear changes such as pleomorphism, hyperchromatism and prominent nucleoli. The mitotic figures are rare. Spread throughout the epithelium and connective tissue are spherical amorhpous calcifications. The recurrence rate is 10-15%. Franklin and Pindborg reported a recurrence rate of 14%. It is considered to have a recurrence rate much lower than the recurrence rate for ameloblastoma.〔 ==Clear Cell Variant== When clear cells are present with clear cytoplasms, then this variant is referred to as "Clear Cell Variant" or CCEOT. The incidence of the clear cell variant is rare: according to this paper written in 1994, there were only 9 known cases reported in the literature. However, this indicates that approximately 8% of CEOTs contain clear cells. And Philipsen et al.〔 indicate that 15 cases of CCEOT have been reported so far (circa 2000). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Calcifying epithelial odontogenic tumor」の詳細全文を読む スポンサード リンク
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