Odontogenic tumour of lip.

There have been nine cases of ;calcifying epithelial odontogenic tumour' described so far. The histological pattern is quite distinctive, and one feature is the presence of abundant intracytoplasmic and stromal material which (Vickers, Dahlin, and Gorlin, 1965) has been shown to react histochemically as amyloid. The tumour is generally believed to be epithelial in origin, arising from the reduced enamel organ of an unerupted tooth with which all the tumours so far recorded are associated. Another case is described, this time arising in the soft tissue of the lip and remote from a tooth. This tumour showed features which suggest that it is of odontoblastic origin and therefore not epithelial. Evidence is also produced to show that the ;amyloid-like' material is not degenerative but probably dentine being actively produced by the tumour cells themselves.