The cervical spine and vasculature appear normal. There is bilateral opacification of the mastoids and middle ear cavities with bony demineralization/thinning and focal dehiscence of the posterior wall of the right mastoid sinus. The dehiscence versus marked thinning is located in the lateral aspect of the posterior wall of the right mastoid sinus. BRAIN: There is a large ring enhancing lesion surrounded by edema in the right cerebellum. It measures approximately 3.3 x 3.4 x 2.7 cm (transverse by A.P.