PMC5283970_01
A, B, C: The left temporal bone CT images (A axial view; B, C multi-planar reconstruction coronal view) show soft-tissue density at the left epitympanum and a partial defect of the left tegmen part of the petrous bone near the lesion (white arrows). D: A right temporal bone CT image of the multi-planar reconstruction coronal view shows thinning of the right tegmen tympani (white-striped arrow). E: A three-dimensional volume-rendering CT image (looking down on the skull base from above; Ziostation, Ziosoft, Tokyo, Japan) depicts 2 bone defects sized 12x9 mm and 9x5 mm at the tegmen tympani part of the left petrous bone (white arrowheads).
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The temporal bone CT images showed soft-tissue density that invaded to the left tympanum and right tegmen tympani thinning (Fig. 1A-D). A 3D volume rendering CT (3D-CT) image (Ziostation; Ziosoft, Tokyo, Japan) revealed 2 petrous bone defects of 12x9 mm and 9x5 mm in size (Fig. 1E).
A: An axial diffusion-weighted image shows several spotty, high-intensity areas along with the cerebral falx, suggesting meningitis-related purulent material (white arrow). B, C: An axial diffusion-weighted image shows a faint high-intensity area, probably due to the T2 shine-through effect of mastoiditis, at the left mastoid cells, but no intense signal (restricted diffusion) suggesting cholesteatoma. An axial T2-weighted image reveals a high-intensity area at the left middle ear corresponding to otitis media (white arrowheads). D, E, F: The axial, coronal, and sagittal contrast-enhanced T1-weighted images show a minimal sac-like left temporal lobe protrusion into the petrous bone defect, suggesting a cephalocele (white-striped arrows).
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Plain MRI showed spotty high-intensity areas along the cerebral falx on diffusion-weighted imaging (Fig. 2A). T1-weighted images showed a minimal sac-like left temporal lobe protrusion into the petrous bone defect, suggesting a cephalocele (Fig. 2D-F).
A, B, C: The intraoperative findings on cranioplasty (looking down on the skull base from above) show the temporal lobe (white arrow) behind the damaged dura mater (white arrowheads). Two petrous bone defects corresponding to those seen on the 3D-CT image (black arrowhead and black-striped line) are visible. The incus is seen in the defect (black-striped arrow).
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The corresponding bone defects shown on the 3D-CT images were observed (Fig. 3A). The damaged dura mater protruded into the tympanum through the bone defect, and the temporal lobe could be seen behind the dura mater (Fig. 3B). The incus was seen in the defect, and it was covered by inflammatory tissue (Fig. 3C).