case_images: PMC10835021_01
case_images: A non-contrast CT scan of the head demonstrates a cystic lesion in the left prepontine cistern with a mass effect on the left pons.
case_images: cureus-0016-00000051549-i01.jpg
case_images: PMC10835021_01_cureus-0016-00000051549-i01.jpg
case_images: FIG1
case_images: A CT scan without contrast of the head showed a cystic lesion in the left prepontine cistern with a mass effect on the left pons (Figure 1).
case_images: An MRI of the brain demonstrates a lesion of the prepontine cistern with a mass effect on the left pons and fourth ventricle, with restricted diffusion and small amounts of internal enhancement. A: T1 imaging, pre-contrast, and post-contrast B: diffusion-weighted imaging and diffusion coefficient imaging
case_images: cureus-0016-00000051549-i02.jpg
case_images: PMC10835021_01_cureus-0016-00000051549-i02.jpg
case_images: FIG2
case_images: Subsequent MRI imaging of the brain with and without contrast showed a lesion of the prepontine cistern with a mass effect on the left pons with restricted diffusion and small amounts of internal enhancement measuring 3.1 cm x 1.7 cm, suspicious for an epidermoid cyst (Figure 2).
case_images: Magnetic resonance angiography projection imaging shows an irregularity within the left internal carotid artery near the carotid canal with a slight loss of flow.
case_images: cureus-0016-00000051549-i03.jpg
case_images: PMC10835021_01_cureus-0016-00000051549-i03.jpg
case_images: FIG3
case_images: A CT angiogram-processed image shows that the epidermoid cyst at the skull base did not cause a gross invasion or occlusion of the left internal carotid artery. Subsequent imaging demonstrated bone loss at the petrous apex and adjacent clivus.
case_images: cureus-0016-00000051549-i04.jpg
case_images: PMC10835021_01_cureus-0016-00000051549-i04.jpg
case_images: FIG4