Primary intraosseous carcinoma of the jaws. Review and update of odontogenic carcinomas.

According to the World Health Organization (WHO) classification system, primary intraosseous carcinoma (PIOC) of the jaw is the terminology recommended in lieu of primary intra-alveolar epidermoid carcinoma (PIAEC) of the jaw. Malignification of odontogenic cysts is now considered a separate entity. Therefore, data garnered from previous case series on PIAEC are not applicable to PIOC. This study reviews the literature on PIOC, excluding central carcinoma cases which arose in odontogenic cysts. Twelve cases were found. The PIOC has a predilection for males (3:1), is noted chiefly in adults, occurs most frequently in the mandible, is histologically nonkeratinizing in 58 percent of the cases, and exhibits peripheral palisading in 58 percent of the cases. A plexiform or alveolar pattern was noted in 67 percent of the cases. The prognosis is quite poor, with only 40 percent of the patients surviving more than 2 years. A modification of the WHO classification system to include "ameloblastic carcinoma" is suggested.