Primary intraosseous carcinoma associated with impacted third molar of the mandible: review of the literature and report of a new case.

This study investigated the clincopathologic features of primary intraosseous carcinoma (PIOC) related to the third molar of the mandible. Six cases (5 from the literature and 1 new case; mean patient age 73 years) of PIOC associated with completely impacted lower third molar were analyzed. For comparison, 8 cases of PIOC presenting after extraction of the lower third molar were also evaluated, with a significantly lower mean patient age of 56 years. Most lesions were deceptively similar to those related to the lateral type of dentigerous cyst, and half of the impacted cases revealed an asymptomatic fracture of the mandible. In all patients except for the present case, metastasis had not been recorded. Surprisingly, no patients are known to have died of PIOC. In our experience the prognosis of PIOC associated with a completely impacted third molar is much better than commonly believed, although the number of cases involved is too small to make a general conclusion. However, delay in establishing the correct diagnosis followed by extraction without awareness of the carcinoma is know to adversely affect the prognosis.