Fig 2. Subject 4. Axial CT scan at the level of the common crus (black arrow) shows a large bone defect caused by presumed AG (white arrow), located at the lateral third of the posterior wall of the left temporal bone. There also is a loss of the posterior wall of the mastoid air cells, which are opacified with fluid. This 41-year-old man presented with CSF otorrhea and recurrent septic meningitis. He underwent dural repair via intact canal wall mastoidectomy. Also noted is a small bone defect caused by presumed AG (arrowhead), located at the lateral third of the posterior wall of right temporal bone.