Peripheral odontogenic fibroma.

The peripheral odontogenic fibroma is characterized by a fibrous or fibromyxomatous proliferation that contains varying amounts of odontogenic or presumed odontogenic epithelium. It has been considered a rare gingival neoplasm that, because of a lack of follow-up information in most reported cases, has had an unknown biologic behavior. Clinical data from this study indicate that the lesion is more common than previously reported and that it has a significant recurrence rate. Light and electron microscopic data reveal a relatively broad spectrum of epithelial and mesenchymal components, including a rare granular cell type. Because the presence of both epithelial and mesenchymal elements are required for its diagnosis, the lesion is logically classified as a mixed epithelial/mesenchymal odontogenic tumor, rather than a purely mesenchymal tumor.