Lesions of the jaws.

The jaws differ in various aspects from all other bones in the skeleton. Embryologically, they are for the major part derived from migrating cells of the cranial neural crest, the so-called ectomesenchyme, and not merely from mesoderm, and they contain teeth. This latter point, especially, results in the presence of lesions that are not found in other bones, a broad variety of odontogenic cysts and tumours. They will be the major topic of this review. Other lesions, not strictly odontogenic but also mainly confined to the jaw bones, are giant cell lesions, fibro-osseous lesions, and the melanotic neuro-ectodermal tumour of infancy. They also will be included in this overview.