Primary intraosseous carcinoma of the mandible with probable origin from reduced enamel epithelium.

This report describes a case of primary intraosseous carcinoma (PIOC) arising de novo in the mandible. The patient was a 74-year-old woman and an early PIOC was found incidentally during histopathological examination of the pericoronal tissue obtained at extraction of a deeply impacted third molar. The curetted soft tissues consisted of a microinvasive, keratinizing squamous cell carcinoma with scattered foci of carcinoma cells showing calcification; stromal osseous metaplasia was also observed. After additional treatment, the patient has remained free of disease for 2 years. Since the tumor was completely enclosed in the bone, the only identifiable source of the present PIOC is the reduced enamel epithelium. Despite its rarity, this case emphasizes the importance of careful histologic examination of all apparently innocuous dental follicles that are removed surgically.