Section Editor: Sandy Cheng-Yu Chen, M.D.
Taipei Medical University Hospital, Taipei, Taiwan
Figure Caption
Hyperostosis cranial interna is a hereditary bone disorder characterized by progressive sclerosis and endosteal hyperostosis involving the calvaria and skull base. Patients present with cranial nerve entrapment symptoms due to narrowing of the internal acoustic canal by the bony bars (A, arrow). Though MRI may show obliteration of the CSF signal within the acoustic canal (B, arrow), it is the CT appearance that is classic.