Calcifying epithelial odontogenic tumour: biological profile based on 181 cases from the literature.

The present profile of the calcifying epithelial odontogenic tumour (CEOT) is based on a literature survey of 181 published tumour cases. The CEOT is a benign, though occasional locally invasive, slow-growing neoplasm occurring as intraosseous (94%) and extraosseous (6%) variants. The intraosseous type appears radiographically as an irregular, uni- or multilocular radiolucent area containing radiopaque masses which increases in size and opacity with time. Some 60% of intraosseous CEOT are associated with an unerupted tooth (or odontoma). CEOT shows a relative frequency of 1-2%. The extraosseous variant is diagnosed slightly earlier (mean age 34.4 years) than the intraosseous type (mean age 38.9 years). Both variants have an almost 1:1 gender ratio. The intraosseous CEOT shows a maxilla:mandible site ratio of 1:2 and are mainly located in the premolar/molar region. The present authors present evidence that the CEOT originates from the complex system of dental laminae or remnants thereof. Histologically, the CEOT is characterized by the occurrence of sheets, nests and masses of polyhedral, eosinophilic epithelial cells which may show cellular abnormalities including giant cell formation and nuclear pleomorphism. Some cells increase in size and produce a homogeneous, eosinophilic, 'amyloid-like' substance which may become calcified and which may be liberated as the cells break down. The true nature of the amyloid-like material is still unresolved. Histological variants including CEOT with cementum-like components, clear-cell CEOT (15 cases reported so far), CEOT-containing Langerhans' cells, combined epithelial odontogenic tumour (CEOT/AOT) and CEOT with myoepithelial cells are discussed in detail. In view of the relatively indolent biological behaviour of the CEOT, mutilating procedures, such as wide resection or hemisection of the mandible, seem unwarranted. Enucleation with a margin of macroscopically normal tissue is, therefore, the recommended treatment for CEOT involving the mandible. Maxillary CEOT should, however, be treated more aggressively, as they tend to grow more rapidly and do not usually remain well confined. Generally, recurrences are rare. Five years is considered the absolute minimum follow-up period. The survey has revealed only one well-documented case of a mandibular CEOT in a 75-year-old man showing features of malignancy.