Comparison of computed tomographic findings for radiolucent lesions of the mandibular ameloblastoma, odontogenic keratocyst, dentigerous cyst, and simple bone cyst.

Background/purpose: Radiolucent lesions of the mandible, including ameloblastoma, odontogenic keratocyst (OKC), dentigerous cyst (DC) and simple bone cyst (SBC), are frequently encountered in clinical practice. However, they vary in type and occasionally in appearance. Each lesion needs a different treatment and approach; therefore, accurate diagnosis is crucial before treatment. However, the radiographic findings, including computed tomography (CT), are often similar. This study aimed to compare the CT findings of 41 ameloblastomas, 74 OKCs, 87 DCs, and 13 SBCs in the mandible. Materials and methods: Patients were evaluated on initial CT images focusing on features such as long/short diameters, relationship with adjacent teeth, cortex appearance, locularity, scalloped margins, and sclerotic rims. Multivariate logistic regression analysis was performed to determine the most useful features for differential diagnosis. Criteria for differential diagnosis were finally established for three lesions, excluding SBC, which had a relatively small number of cases. Results: The relationship with the affected tooth, short diameters, sclerotic rims, and locularity were found to be significant features in the differential diagnosis. Ameloblastomas were characterized by relatively larger short diameters, frequently accompanied by root resorption and adjacent tooth displacement, while SBCs lacked these features. Sclerotic rims were commonly observed in OKCs and DCs, and most DCs were unilocular, containing a crown within the lesion. Based on these results, criteria were established for differential diagnosis with a diagnostic accuracy of 84.2%. Conclusion: This is the first study to attempt to characterize each lesion's radiological features, and these criteria are likely to assist in clinical diagnosis.