AC omparative Study of Sporadic and Multiple Keratocystic Odontogenic Tumor : a Review of 196 Tumors

F rom the files of the Division of Pathology, Department of Diagnosis & Therapeutic Sciences, Meikai Uni- versity School of Dentistry, 196 tumors diagnosed as keratocystic odontogenic tumor (KCOT) based on the guidelines of the 2005 classification of the World Health Organization (WHO) were studied. The features of 152 sporadic KCOTs were compared with those of 44 multiple KCOTs. The age and sex of the patients, the site of occurrence, and the association with nevoid basal cell carcinoma syndrome were taken in consideration. The mean age of patients with multiple KCOTs was lower (22.9 years) than that of patients with sporadic KCOTs (35.6 years). The peak incidence of the tumors was in the third and second decades of life for single and multiple KCOTs respectively. There were no significant histological differ- ences between the two groups except for a greater amount of daughter cysts and a tendency for multiple recurrence in the multiple KCOT group. The term multiple KCOT refers to the lifetime history of the patient and does not necessarily imply that more than one tumor is present at a given time.