Ultrastructural study of an odontogenic myxoma.

Ultrastructural study of an odontogenic myxoma has revealed two basic types of tumor cells: secretory and nonsecretory. The secretory cell type is the principal tumor cell and resembles the fibroblast in many respects. Although the ultrastructural findings indicate an abortive attempt at collagen fibrillogenesis, there is at the same time prominent secretory activity within the tumor cells, resulting in excessive production of acid mucopolysaccharide ground substance. There may also be phagocytosis by tumor cells of residual collagen in the area compatible with an odontogenic origin, they are not incompatible with an origin from primitive nonodonotogenic mesenchymal rests.