Figure 1: Right ear axial CT (A) showing a supralabytinthine petrous bone cholesteatoma eroding the inner ear vestibule and the bone of the posterior cranial fossa (arrow). Right ear coronal CT (B) showing erosion of the superior and lateral semicircular canals and the bone of the middle cranial fossa (arrow). Right ear coronal CT (C) showing erosion of the middle cranial fossa (arrow) but sparing the cochlea.