Abstract
A variety of diffuse diseases affect the calvaria. They may be identified clinically as palpable masses or incidentally in radiologic examinations. The purpose of this study is to illustrate the main diffuse calvarial lesions starting from a case report of fibrous dysplasia of the cranial vault. A 68-year-old male patient who presented with a history of right otalgia and bloody otorrhea was diagnosed to have fibrous dysplasia based on the radiological features. Most diffuse diseases of the calvaria are benign non-neoplastic lesions of unknown origin. The radiologist has a long list of differential diagnosis and their true etiology may be puzzling when the medical evaluation is based only on imaging findings.