Multilocularity as a radiographic marker of the keratocystic odontogenic tumor.

PURPOSE: The purpose of this study was to answer this clinical question: When a patient presents with a radiolucent lesion of the mandible presumed to be an odontogenic cystic lesion, to what extent is the radiographic finding of multilocularity predictive of a final diagnosis of keratocystic odontogenic tumor (KCOT)?

MATERIALS AND METHODS: The study sample was derived from the population of patients who presented to the Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital for evaluation and management of suspected mandibular lesions from January 1991 through January 2009. Subjects were eligible for study inclusion if there was a final histologic diagnosis of KCOT or dentigerous cyst. The predictor variable was radiographic appearance of the lesion and was grouped into 2 categories (unilocular or multilocular). The outcome variable was lesion type (KCOT or dentigerous cyst). Appropriate univariate, bivariate, and multivariate statistics were computed. Statistical significance was defined as P < .05.

RESULTS: The study consisted of 130 subjects. Multilocular lesions were 1.7 times more likely to be KCOTs than unilocular lesions (P = .0001). The sensitivity, specificity, and positive and negative predictive values were 0.48, 0.87, 0.86, and 0.49, respectively. In the multiple logistic regression model, a multilocular radiographic appearance was associated with a 12-fold (95% confidence interval, 3.7 to 38) increased risk of KCOT.

CONCLUSION: The results of this study confirm the hypothesis that radiographic multilocularity is predictive of a KCOT because it is associated with a 12-fold increased risk for the diagnosis of KCOT.