Diagnosis of coronoid process hyperplasia by three-dimensional computed tomographic imaging

Three-dimensional (3D) CT imaging was performed on three cases (one unilateral, two bilateral) of coronoid process hyperplasia. This technique displayed the impingement of the enlarged coronoid process on an exostosis on the lower border of the malar bone. In addition, a small concavity was found on the inner surface of the malar bone that was not displayed by other imaging modalities. The 3D images were useful in planning surgical treatment. In cases of limitation of opening, finding a malar exostosis on conventional radiographs such as a Water's view should suggest the presence of coronoid process hyperplasia even if the impingement cannot be demonstrated.