OBJECTIVES/HYPOTHESIS: Malignant odontogenic tumors are exceedingly rare and arise from odontogenic epithelial residues and odontogenic cysts in the jaw bones. Odontogenic malignancies have various origins. Some develop directly from the remnants of odontogenic epithelium left after completion of dental development; others may result from malignant transformation of a benign odontogenic cyst or ameloblastoma. These lesions are usually locally aggressive with radical surgery being the primary mode of treatment. Because of their rarity, much of the existing information about malignant odontogenic tumors with regard to their origin, clinicopathological features, biological behavior, and therapeutics is derived from case reports or small series. The study represents one of the largest series of malignant odontogenic tumors compiled in a single institution.

STUDY DESIGN

Retrospective 22-year review from an Academic Medical Center.

METHODS

Twenty cases of reported malignant odontogenic tumors were diagnosed in the authors' institution between 1981 and 2002. All pathological slides were reviewed to reconfirm diagnosis. Malignancy was confirmed based on the following criteria: histological findings of infiltrative growth, atypical cytological features, and focal necrosis or clear evidence of distant metastatic spread. Patient age, race, sex, treatment and outcome were recorded on chart review.

RESULTS

Of the twenty reported cases, only nine were actually found to be malignant tumors on re-evaluation. These consisted of four cases of malignant ameloblastomas, two cases of ameloblastic carcinoma, one case of malignant Pindborg tumor (calcifying epithelial odontogenic tumor), one case of odontogenic ghost cell carcinoma, and one case of squamous cell carcinoma arising in an odontogenic keratocyst. The racial demographics were six Caucasian patients, one African American patient, and two Asian patients; seven men and two women represented the gender distribution. Tumors of six cases were located in the mandible, and of three cases, in the maxilla. All cases were treated with radical surgical excision. Two patients died of their disease, three patients were alive and free of disease, and four patients were lost to follow-up.

CONCLUSION

Malignant odontogenic tumors are rare. They require a multidisciplinary team to determine proper treatment. Long-term surveillance is mandatory and is accomplished by routine physical examinations, along with serial radiographic imaging.